# AST Matcher Reference

This document shows all currently implemented matchers. The matchers are grouped by category and node type they match. You can click on matcher names to show the matcher's source documentation.

There are three different basic categories of matchers:

- Node Matchers: Matchers that match a specific type of AST node.
- Narrowing Matchers: Matchers that match attributes on AST nodes.
- Traversal Matchers: Matchers that allow traversal between AST nodes.

Within each category the matchers are ordered by node type they match on. Note that if a matcher can match multiple node types, it will appear multiple times. This means that by searching for Matcher<Stmt> you can find all matchers that can be used to match on Stmt nodes.

The exception to that rule are matchers that can match on any node. Those are marked with a * and are listed in the beginning of each category.

Note that the categorization of matchers is a great help when you combine them into matcher expressions. You will usually want to form matcher expressions that read like english sentences by alternating between node matchers and narrowing or traversal matchers, like this:

    recordDecl(hasDescendant(
        ifStmt(hasTrueExpression(
            expr(hasDescendant(
                ifStmt()))))))

## Traverse Mode

The default mode of operation of AST Matchers visits all nodes in the AST, even if they are not spelled in the source. This is AsIs mode. This mode requires writing AST matchers that explicitly traverse or ignore implicit nodes, such as parentheses surrounding an expression or expressions with cleanups. These implicit nodes are not always obvious from the syntax of the source code, and so this mode requires careful consideration and testing to get the desired behavior from an AST matcher.

In addition, because template instantiations are matched in the default mode, transformations can be accidentally made to template declarations. Finally, because implicit nodes are matched by default, transformations can be made on entirely incorrect places in the code.

For these reasons, it is possible to ignore AST nodes which are not spelled in the source using the IgnoreUnlessSpelledInSource mode. This is likely to be far less error-prone for users who are not already very familiar with where implicit nodes appear in the AST. It is also likely to be less error-prone for experienced AST users, as difficult cases do not need to be encountered and matcher expressions adjusted for these cases.

In clang-query, the mode can be changed with

    set traversal IgnoreUnlessSpelledInSource

This affects both matchers and AST dump output in results.

When using the C++ API such as in clang-tidy checks, the traverse() matcher is used to set the mode:

    Finder->addMatcher(traverse(TK_IgnoreUnlessSpelledInSource,
      returnStmt(hasReturnArgument(integerLiteral(equals(0))))
      ), this);

The following table compares the AsIs mode with the IgnoreUnlessSpelledInSource mode:

| AsIs | IgnoreUnlessSpelledInSource
--- | --- | ---
AST dump of func1:
    struct B {
      B(int);
    };

    B func1() { return 42; }
| C++98 dialect:
    FunctionDecl
    `-CompoundStmt
      `-ReturnStmt
        `-ExprWithCleanups
          `-CXXConstructExpr
            `-MaterializeTemporaryExpr
              `-ImplicitCastExpr
                `-ImplicitCastExpr
                  `-CXXConstructExpr
                    `-IntegerLiteral 'int' 42
C++11, C++14 dialect:
    FunctionDecl
    `-CompoundStmt
      `-ReturnStmt
        `-ExprWithCleanups
          `-CXXConstructExpr
            `-MaterializeTemporaryExpr
              `-ImplicitCastExpr
                `-CXXConstructExpr
                  `-IntegerLiteral 'int' 42
C++17, C++20 dialect:
    FunctionDecl
    `-CompoundStmt
      `-ReturnStmt
        `-ImplicitCastExpr
          `-CXXConstructExpr
            `-IntegerLiteral 'int' 42
| All dialects:
    FunctionDecl
    `-CompoundStmt
      `-ReturnStmt
        `-IntegerLiteral 'int' 42
Matcher for returned 42:
    struct B {
      B(int);
    };

    B func1() { return 42; }
| All dialects:
    returnStmt(hasReturnValue(
        ignoringImplicit(
            ignoringElidableConstructorCall(
                ignoringImplicit(
                    cxxConstructExpr(hasArgument(0,
                        ignoringImplicit(
                            integerLiteral().bind("returnVal")
                            )
                        ))
                    )
                )
            )
        ))
| All dialects:
    returnStmt(hasReturnValue(
        integerLiteral().bind("returnVal")
    ))
Match result for
    implicitCastExpr()
given:
    struct B {
      B(int);
    };

    B func1() { return 42; }
| Match found. | No match.
Match result for:
    cxxConstructorDecl(
      isCopyConstructor()
      ).bind("prepend_explicit")
given:
    struct Other {};
    struct Copyable {
      Other m_o;
      Copyable();
    };
| Match found. Insertion produces incorrect output:
    struct Other {};
    struct explicit Copyable {
      Other m_o;
      Copyable();
    };
| No match found. Incorrect replacement not possible.
Replacement of begin() with cbegin():
    cxxMemberCallExpr(
      on(ConstContainerExpr),
      callee(cxxMethodDecl(hasName("begin")))
      ).bind("replace_with_cbegin")
given:
    void foo() {
      const Container c;
      c.begin();

      for (auto i : c) {
      }
    }
| 2 matches found. Replacement produces incorrect output:
    void foo() {
      const Container c;
      c.cbegin();

      for (auto i :.cbegin() c) {
      }
    }
| 1 match found. Replacement produces correct output:
    void foo() {
      const Container c;
      c.cbegin();

      for (auto i : c) {
      }
    }
Replacement of int member with safe_int:
    fieldDecl(
      hasType(asString("int"))
      ).bind("use_safe_int")
given:
    struct S {
      int m_i;
    };

    template <typename T> struct TemplStruct {
      TemplStruct() {}
      ~TemplStruct() {}

    private:
      T m_t;
    };

    void instantiate() { TemplStruct<int> ti; }
| 2 matches found. Replacement produces incorrect output:
    struct S {
      safe_int m_i;
    };

    template <typename T> struct TemplStruct {
      TemplStruct() {}
      ~TemplStruct() {}

    private:
      safe_int m_t;
    };

    void instantiate() { TemplStruct<int> ti; }
| 1 match found. Replacement produces correct output:
    struct S {
      safe_int m_i;
    };

    template <typename T> struct TemplStruct {
      TemplStruct() {}
      ~TemplStruct() {}

    private:
      T m_t;
    };

    void instantiate() { TemplStruct<int> ti; }
Add prefix to member initializer
    cxxCtorInitializer(
      forField(fieldDecl())
      ).bind("add_prefix")
given:
    struct Simple {};

    struct Record {
      Record() : i(42) {}
    private:
      int i;
      Simple s;
    };
| 2 matches found. Replacement produces incorrect output:
    struct Simple {};

    struct Record {
      m_Record() : m_i(42) {}
    private:
      int i;
      Simple s;
    };
| 1 match found. Replacement produces correct output:
    struct Simple {};

    struct Record {
      Record() : m_i(42) {}
    private:
      int i;
      Simple s;
    };
Ignored default arguments
    callExpr(
      callee(functionDecl(
        hasName("hasDefaultArg")
        )),
      argumentCountIs(1)
      ).bind("add_prefix")
given:
    void hasDefaultArg(int i, int j = 0) {}
    void callDefaultArg() { hasDefaultArg(42); }
| No match. | 1 match found.
Lambda fields
    fieldDecl(
      hasType(asString("int"))
      ).bind("make_safe")
given:
    struct S {
      int m_i;
    };

    void func() {
      int a = 0;
      int c = 0;

      auto l = [a, b = c](int d) { int e = d; };
      l(43);
    }
| 2 matches found. Replacement produces incorrect output:
    struct S {
      safe_int m_i;
    };

    void func() {
      int a = 0;
      int c = 0;

      auto l = [safe_a, safe_b = c](int d) { int e = d; };
      l(43);
    }
| 1 match found. Replacement produces correct output:
    struct S {
      safe_int m_i;
    };

    void func() {
      int a = 0;
      int c = 0;

      auto l = [a, b = c](int d) { int e = d; };
      l(43);
    }
Rewritten binary operators
    binaryOperator(
      hasOperatorName("<"),
      hasRHS(integerLiteral(equals(0)))
      )
given:
    #include <compare>

    class HasSpaceship {
    public:
       int x;
       bool operator==(const HasSpaceship&) const = default;
       std::strong_ordering operator<=>(const HasSpaceship&) const = default;
    };

    bool isLess(const HasSpaceship& a, const HasSpaceship& b) {
       return a < b;
    }
| 1 match found. | No match found.

## Node Matchers

Node matchers are at the core of matcher expressions - they specify the type of node that is expected. Every match expression starts with a node matcher, which can then be further refined with a narrowing or traversal matcher. All traversal matchers take node matchers as their arguments.

For convenience, all node matchers take an arbitrary number of arguments and implicitly act as allOf matchers.

Node matchers are the only matchers that support the bind("id") call to bind the matched node to the given string, to be later retrieved from the match callback.

It is important to remember that the arguments to node matchers are predicates on the same node, just with additional information about the type. This is often useful to make matcher expression more readable by inlining bind calls into redundant node matchers inside another node matcher:

    // This binds the CXXRecordDecl to "id", as the decl() matcher will stay on
    // the same node.
    recordDecl(decl().bind("id"), hasName("::MyClass"))

Return type | Name | Parameters
--- | --- | ---
Matcher<CXXCtorInitializer> | cxxCtorInitializer | Matcher<CXXCtorInitializer>...
    Matches constructor initializers.

    Examples matches i(42).
      class C {
        C() : i(42) {}
        int i;
      };
Matcher<Decl> | accessSpecDecl | Matcher<AccessSpecDecl>...
    Matches C++ access specifier declarations.

    Given
      class C {
      public:
        int a;
      };
    accessSpecDecl()
      matches 'public:'
Matcher<Decl> | blockDecl | Matcher<BlockDecl>...
    Matches block declarations.

    Example matches the declaration of the nameless block printing an input
    integer.

      myFunc(^(int p) {
        printf("%d", p);
      })
Matcher<Decl> | classTemplateDecl | Matcher<ClassTemplateDecl>...
    Matches C++ class template declarations.

    Example matches Z
      template<class T> class Z {};
Matcher<Decl> | classTemplatePartialSpecializationDecl | Matcher<ClassTemplatePartialSpecializationDecl>...
    Matches C++ class template partial specializations.

    Given
      template<class T1, class T2, int I>
      class A {};

      template<class T, int I>
      class A<T, T*, I> {};

      template<>
      class A<int, int, 1> {};
    classTemplatePartialSpecializationDecl()
      matches the specialization A<T,T*,I> but not A<int,int,1>
Matcher<Decl> | classTemplateSpecializationDecl | Matcher<ClassTemplateSpecializationDecl>...
    Matches C++ class template specializations.

    Given
      template<typename T> class A {};
      template<> class A<double> {};
      A<int> a;
    classTemplateSpecializationDecl()
      matches the specializations A<int> and A<double>
Matcher<Decl> | cxxConstructorDecl | Matcher<CXXConstructorDecl>...
    Matches C++ constructor declarations.

    Example matches Foo::Foo() and Foo::Foo(int)
      class Foo {
       public:
        Foo();
        Foo(int);
        int DoSomething();
      };
Matcher<Decl> | cxxConversionDecl | Matcher<CXXConversionDecl>...
    Matches conversion operator declarations.

    Example matches the operator.
      class X { operator int() const; };
Matcher<Decl> | cxxDeductionGuideDecl | Matcher<CXXDeductionGuideDecl>...
    Matches user-defined and implicitly generated deduction guide.

    Example matches the deduction guide.
      template<typename T>
      class X { X(int) };
      X(int) -> X<int>;
Matcher<Decl> | cxxDestructorDecl | Matcher<CXXDestructorDecl>...
    Matches explicit C++ destructor declarations.

    Example matches Foo::~Foo()
      class Foo {
       public:
        virtual ~Foo();
      };
Matcher<Decl> | cxxMethodDecl | Matcher<CXXMethodDecl>...
    Matches method declarations.

    Example matches y
      class X { void y(); };
Matcher<Decl> | cxxRecordDecl | Matcher<CXXRecordDecl>...
    Matches C++ class declarations.

    Example matches X, Z
      class X;
      template<class T> class Z {};
Matcher<Decl> | decl | Matcher<Decl>...
    Matches declarations.

    Examples matches X, C, and the friend declaration inside C;
      void X();
      class C {
        friend X;
      };
Matcher<Decl> | declaratorDecl | Matcher<DeclaratorDecl>...
    Matches declarator declarations (field, variable, function
    and non-type template parameter declarations).

    Given
      class X { int y; };
    declaratorDecl()
      matches int y.
Matcher<Decl> | enumConstantDecl | Matcher<EnumConstantDecl>...
    Matches enum constants.

    Example matches A, B, C
      enum X {
        A, B, C
      };
Matcher<Decl> | enumDecl | Matcher<EnumDecl>...
    Matches enum declarations.

    Example matches X
      enum X {
        A, B, C
      };
Matcher<Decl> | fieldDecl | Matcher<FieldDecl>...
    Matches field declarations.

    Given
      class X { int m; };
    fieldDecl()
      matches 'm'.
Matcher<Decl> | friendDecl | Matcher<FriendDecl>...
    Matches friend declarations.

    Given
      class X { friend void foo(); };
    friendDecl()
      matches 'friend void foo()'.
Matcher<Decl> | functionDecl | Matcher<FunctionDecl>...
    Matches function declarations.

    Example matches f
      void f();
Matcher<Decl> | functionTemplateDecl | Matcher<FunctionTemplateDecl>...
    Matches C++ function template declarations.

    Example matches f
      template<class T> void f(T t) {}
Matcher<Decl> | indirectFieldDecl | Matcher<IndirectFieldDecl>...
    Matches indirect field declarations.

    Given
      struct X { struct { int a; }; };
    indirectFieldDecl()
      matches 'a'.
Matcher<Decl> | labelDecl | Matcher<LabelDecl>...
    Matches a declaration of label.

    Given
      goto FOO;
      FOO: bar();
    labelDecl()
      matches 'FOO:'
Matcher<Decl> | linkageSpecDecl | Matcher<LinkageSpecDecl>...
    Matches a declaration of a linkage specification.

    Given
      extern "C" {}
    linkageSpecDecl()
      matches "extern "C" {}"
Matcher<Decl> | namedDecl | Matcher<NamedDecl>...
    Matches a declaration of anything that could have a name.

    Example matches X, S, the anonymous union type, i, and U;
      typedef int X;
      struct S {
        union {
          int i;
        } U;
      };
Matcher<Decl> | namespaceAliasDecl | Matcher<NamespaceAliasDecl>...
    Matches a declaration of a namespace alias.

    Given
      namespace test {}
      namespace alias = ::test;
    namespaceAliasDecl()
      matches "namespace alias" but not "namespace test"
Matcher<Decl> | namespaceDecl | Matcher<NamespaceDecl>...
    Matches a declaration of a namespace.

    Given
      namespace {}
      namespace test {}
    namespaceDecl()
      matches "namespace {}" and "namespace test {}"
Matcher<Decl> | nonTypeTemplateParmDecl | Matcher<NonTypeTemplateParmDecl>...
    Matches non-type template parameter declarations.

    Given
      template <typename T, int N> struct C {};
    nonTypeTemplateParmDecl()
      matches 'N', but not 'T'.
Matcher<Decl> | objcCategoryDecl | Matcher<ObjCCategoryDecl>...
    Matches Objective-C category declarations.

    Example matches Foo (Additions)
      @interface Foo (Additions)
      @end
Matcher<Decl> | objcCategoryImplDecl | Matcher<ObjCCategoryImplDecl>...
    Matches Objective-C category definitions.

    Example matches Foo (Additions)
      @implementation Foo (Additions)
      @end
Matcher<Decl> | objcImplementationDecl | Matcher<ObjCImplementationDecl>...
    Matches Objective-C implementation declarations.

    Example matches Foo
      @implementation Foo
      @end
Matcher<Decl> | objcInterfaceDecl | Matcher<ObjCInterfaceDecl>...
    Matches Objective-C interface declarations.

    Example matches Foo
      @interface Foo
      @end
Matcher<Decl> | objcIvarDecl | Matcher<ObjCIvarDecl>...
    Matches Objective-C instance variable declarations.

    Example matches _enabled
      @implementation Foo {
        BOOL _enabled;
      }
      @end
Matcher<Decl> | objcMethodDecl | Matcher<ObjCMethodDecl>...
    Matches Objective-C method declarations.

    Example matches both declaration and definition of -[Foo method]
      @interface Foo
      - (void)method;
      @end

      @implementation Foo
      - (void)method {}
      @end
Matcher<Decl> | objcPropertyDecl | Matcher<ObjCPropertyDecl>...
    Matches Objective-C property declarations.

    Example matches enabled
      @interface Foo
      @property BOOL enabled;
      @end
Matcher<Decl> | objcProtocolDecl | Matcher<ObjCProtocolDecl>...
    Matches Objective-C protocol declarations.

    Example matches FooDelegate
      @protocol FooDelegate
      @end
Matcher<Decl> | parmVarDecl | Matcher<ParmVarDecl>...
    Matches parameter variable declarations.

    Given
      void f(int x);
    parmVarDecl()
      matches int x.
Matcher<Decl> | recordDecl | Matcher<RecordDecl>...
    Matches class, struct, and union declarations.

    Example matches X, Z, U, and S
      class X;
      template<class T> class Z {};
      struct S {};
      union U {};
Matcher<Decl> | staticAssertDecl | Matcher<StaticAssertDecl>...
    Matches a C++ static_assert declaration.

    Example:
      staticAssertExpr()
    matches
      static_assert(sizeof(S) == sizeof(int))
    in
      struct S {
        int x;
      };
      static_assert(sizeof(S) == sizeof(int));
Matcher<Decl> | tagDecl | Matcher<TagDecl>...
    Matches tag declarations.

    Example matches X, Z, U, S, E
      class X;
      template<class T> class Z {};
      struct S {};
      union U {};
      enum E {
        A, B, C
      };
Matcher<Decl> | templateTemplateParmDecl | Matcher<TemplateTemplateParmDecl>...
    Matches template template parameter declarations.

    Given
      template <template <typename> class Z, int N> struct C {};
    templateTypeParmDecl()
      matches 'Z', but not 'N'.
Matcher<Decl> | templateTypeParmDecl | Matcher<TemplateTypeParmDecl>...
    Matches template type parameter declarations.

    Given
      template <typename T, int N> struct C {};
    templateTypeParmDecl()
      matches 'T', but not 'N'.
Matcher<Decl> | translationUnitDecl | Matcher<TranslationUnitDecl>...
    Matches the top declaration context.

    Given
      int X;
      namespace NS {
      int Y;
      }  // namespace NS
    decl(hasDeclContext(translationUnitDecl()))
      matches "int X", but not "int Y".
Matcher<Decl> | typeAliasDecl | Matcher<TypeAliasDecl>...
    Matches type alias declarations.

    Given
      typedef int X;
      using Y = int;
    typeAliasDecl()
      matches "using Y = int", but not "typedef int X"
Matcher<Decl> | typeAliasTemplateDecl | Matcher<TypeAliasTemplateDecl>...
    Matches type alias template declarations.

    typeAliasTemplateDecl() matches
      template <typename T>
      using Y = X<T>;
Matcher<Decl> | typedefDecl | Matcher<TypedefDecl>...
    Matches typedef declarations.

    Given
      typedef int X;
      using Y = int;
    typedefDecl()
      matches "typedef int X", but not "using Y = int"
Matcher<Decl> | typedefNameDecl | Matcher<TypedefNameDecl>...
    Matches typedef name declarations.

    Given
      typedef int X;
      using Y = int;
    typedefNameDecl()
      matches "typedef int X" and "using Y = int"
Matcher<Decl> | unresolvedUsingTypenameDecl | Matcher<UnresolvedUsingTypenameDecl>...
    Matches unresolved using value declarations that involve the
    typename.

    Given
      template <typename T>
      struct Base { typedef T Foo; };

      template<typename T>
      struct S : private Base<T> {
        using typename Base<T>::Foo;
      };
    unresolvedUsingTypenameDecl()
      matches using Base<T>::Foo
Matcher<Decl> | unresolvedUsingValueDecl | Matcher<UnresolvedUsingValueDecl>...
    Matches unresolved using value declarations.

    Given
      template<typename X>
      class C : private X {
        using X::x;
      };
    unresolvedUsingValueDecl()
      matches using X::x
Matcher<Decl> | usingDecl | Matcher<UsingDecl>...
    Matches using declarations.

    Given
      namespace X { int x; }
      using X::x;
    usingDecl()
      matches using X::x
Matcher<Decl> | usingDirectiveDecl | Matcher<UsingDirectiveDecl>...
    Matches using namespace declarations.

    Given
      namespace X { int x; }
      using namespace X;
    usingDirectiveDecl()
      matches using namespace X
Matcher<Decl> | valueDecl | Matcher<ValueDecl>...
    Matches any value declaration.

    Example matches A, B, C and F
      enum X { A, B, C };
      void F();
Matcher<Decl> | varDecl | Matcher<VarDecl>...
    Matches variable declarations.

    Note: this does not match declarations of member variables, which are
    "field" declarations in Clang parlance.

    Example matches a
      int a;
Matcher<DecompositionDecl> | decompositionDecl | Matcher<DecompositionDecl>...
    Matches decomposition-declarations.

    Examples matches the declaration node with foo and bar, but not
    number.
    (matcher = declStmt(has(decompositionDecl())))

      int number = 42;
      auto [foo, bar] = std::make_pair{42, 42};
Matcher<NestedNameSpecifierLoc> | nestedNameSpecifierLoc | Matcher<NestedNameSpecifierLoc>...
    Same as nestedNameSpecifier but matches NestedNameSpecifierLoc.
Matcher<NestedNameSpecifier> | nestedNameSpecifier | Matcher<NestedNameSpecifier>...
    Matches nested name specifiers.

    Given
      namespace ns {
        struct A { static void f(); };
        void A::f() {}
        void g() { A::f(); }
      }
      ns::A a;
    nestedNameSpecifier()
      matches "ns::" and both "A::"
Matcher<OMPClause> | ompDefaultClause | Matcher<OMPDefaultClause>...
    Matches OpenMP ``default`` clause.

    Given

      #pragma omp parallel default(none)
      #pragma omp parallel default(shared)
      #pragma omp parallel default(firstprivate)
      #pragma omp parallel

    ``ompDefaultClause()`` matches ``default(none)``, ``default(shared)``, and
    ``default(firstprivate)``
Matcher<QualType> | qualType | Matcher<QualType>...
    Matches QualTypes in the clang AST.
Matcher<Stmt> | addrLabelExpr | Matcher<AddrLabelExpr>...
    Matches address of label statements (GNU extension).

    Given
      FOO: bar();
      void *ptr = &&FOO;
      goto *bar;
    addrLabelExpr()
      matches '&&FOO'
Matcher<Stmt> | arraySubscriptExpr | Matcher<ArraySubscriptExpr>...
    Matches array subscript expressions.

    Given
      int i = a[1];
    arraySubscriptExpr()
      matches "a[1]"
Matcher<Stmt> | asmStmt | Matcher<AsmStmt>...
    Matches asm statements.

     int i = 100;
      __asm("mov al, 2");
    asmStmt()
      matches '__asm("mov al, 2")'
Matcher<Stmt> | atomicExpr | Matcher<AtomicExpr>...
    Matches atomic builtins.
    Example matches __atomic_load_n(ptr, 1)
      void foo() { int *ptr; __atomic_load_n(ptr, 1); }
Matcher<Stmt> | autoreleasePoolStmt | Matcher<ObjCAutoreleasePoolStmt>...
    Matches an Objective-C autorelease pool statement.

    Given
      @autoreleasepool {
        int x = 0;
      }
    autoreleasePoolStmt(stmt()) matches the declaration of "x"
    inside the autorelease pool.
Matcher<Stmt> | binaryConditionalOperator | Matcher<BinaryConditionalOperator>...
    Matches binary conditional operator expressions (GNU extension).

    Example matches a ?: b
      (a ?: b) + 42;
Matcher<Stmt> | binaryOperator | Matcher<BinaryOperator>...
    Matches binary operator expressions.

    Example matches a || b
      !(a || b)
    See also the binaryOperation() matcher for more-general matching.
Matcher<Stmt> | blockExpr | Matcher<BlockExpr>...
    Matches a reference to a block.

    Example: matches "^{}":
      void f() { ^{}(); }
Matcher<Stmt> | breakStmt | Matcher<BreakStmt>...
    Matches break statements.

    Given
      while (true) { break; }
    breakStmt()
      matches 'break'
Matcher<Stmt> | cStyleCastExpr | Matcher<CStyleCastExpr>...
    Matches a C-style cast expression.

    Example: Matches (int) 2.2f in
      int i = (int) 2.2f;
Matcher<Stmt> | callExpr | Matcher<CallExpr>...
    Matches call expressions.

    Example matches x.y() and y()
      X x;
      x.y();
      y();
Matcher<Stmt> | caseStmt | Matcher<CaseStmt>...
    Matches case statements inside switch statements.

    Given
      switch(a) { case 42: break; default: break; }
    caseStmt()
      matches 'case 42:'.
Matcher<Stmt> | castExpr | Matcher<CastExpr>...
    Matches any cast nodes of Clang's AST.

    Example: castExpr() matches each of the following:
      (int) 3;
      const_cast<Expr *>(SubExpr);
      char c = 0;
    but does not match
      int i = (0);
      int k = 0;
Matcher<Stmt> | characterLiteral | Matcher<CharacterLiteral>...
    Matches character literals (also matches wchar_t).

    Not matching Hex-encoded chars (e.g. 0x1234, which is a IntegerLiteral),
    though.

    Example matches 'a', L'a'
      char ch = 'a';
      wchar_t chw = L'a';
Matcher<Stmt> | chooseExpr | Matcher<ChooseExpr>...
    Matches GNU __builtin_choose_expr.
Matcher<Stmt> | compoundLiteralExpr | Matcher<CompoundLiteralExpr>...
    Matches compound (i.e. non-scalar) literals

    Example match: {1}, (1, 2)
      int array[4] = {1};
      vector int myvec = (vector int)(1, 2);
Matcher<Stmt> | compoundStmt | Matcher<CompoundStmt>...
    Matches compound statements.

    Example matches '{}' and '{{}}' in 'for (;;) {{}}'
      for (;;) {{}}
Matcher<Stmt> | conditionalOperator | Matcher<ConditionalOperator>...
    Matches conditional operator expressions.

    Example matches a ? b : c
      (a ? b : c) + 42
Matcher<Stmt> | constantExpr | Matcher<ConstantExpr>...
    Matches a constant expression wrapper.

    Example matches the constant in the case statement:
        (matcher = constantExpr())
      switch (a) {
      case 37: break;
      }
Matcher<Stmt> | continueStmt | Matcher<ContinueStmt>...
    Matches continue statements.

    Given
      while (true) { continue; }
    continueStmt()
      matches 'continue'
Matcher<Stmt> | cudaKernelCallExpr | Matcher<CUDAKernelCallExpr>...
    Matches CUDA kernel call expression.

    Example matches,
      kernel<<<i,j>>>();
Matcher<Stmt> | cxxBindTemporaryExpr | Matcher<CXXBindTemporaryExpr>...
    Matches nodes where temporaries are created.

    Example matches FunctionTakesString(GetStringByValue())
        (matcher = cxxBindTemporaryExpr())
      FunctionTakesString(GetStringByValue());
      FunctionTakesStringByPointer(GetStringPointer());
Matcher<Stmt> | cxxBoolLiteral | Matcher<CXXBoolLiteralExpr>...
    Matches bool literals.

    Example matches true
      true
Matcher<Stmt> | cxxCatchStmt | Matcher<CXXCatchStmt>...
    Matches catch statements.

      try {} catch(int i) {}
    cxxCatchStmt()
      matches 'catch(int i)'
Matcher<Stmt> | cxxConstCastExpr | Matcher<CXXConstCastExpr>...
    Matches a const_cast expression.

    Example: Matches const_cast<int*>(&r) in
      int n = 42;
      const int &r(n);
      int* p = const_cast<int*>(&r);
Matcher<Stmt> | cxxConstructExpr | Matcher<CXXConstructExpr>...
    Matches constructor call expressions (including implicit ones).

    Example matches string(ptr, n) and ptr within arguments of f
        (matcher = cxxConstructExpr())
      void f(const string &a, const string &b);
      char *ptr;
      int n;
      f(string(ptr, n), ptr);
Matcher<Stmt> | cxxDefaultArgExpr | Matcher<CXXDefaultArgExpr>...
    Matches the value of a default argument at the call site.

    Example matches the CXXDefaultArgExpr placeholder inserted for the
        default value of the second parameter in the call expression f(42)
        (matcher = cxxDefaultArgExpr())
      void f(int x, int y = 0);
      f(42);
Matcher<Stmt> | cxxDeleteExpr | Matcher<CXXDeleteExpr>...
    Matches delete expressions.

    Given
      delete X;
    cxxDeleteExpr()
      matches 'delete X'.
Matcher<Stmt> | cxxDependentScopeMemberExpr | Matcher<CXXDependentScopeMemberExpr>...
    Matches member expressions where the actual member referenced could not be
    resolved because the base expression or the member name was dependent.

    Given
      template <class T> void f() { T t; t.g(); }
    cxxDependentScopeMemberExpr()
      matches t.g
Matcher<Stmt> | cxxDynamicCastExpr | Matcher<CXXDynamicCastExpr>...
    Matches a dynamic_cast expression.

    Example:
      cxxDynamicCastExpr()
    matches
      dynamic_cast<D*>(&b);
    in
      struct B { virtual ~B() {} }; struct D : B {};
      B b;
      D* p = dynamic_cast<D*>(&b);
Matcher<Stmt> | cxxForRangeStmt | Matcher<CXXForRangeStmt>...
    Matches range-based for statements.

    cxxForRangeStmt() matches 'for (auto a : i)'
      int i[] =  {1, 2, 3}; for (auto a : i);
      for(int j = 0; j < 5; ++j);
Matcher<Stmt> | cxxFunctionalCastExpr | Matcher<CXXFunctionalCastExpr>...
    Matches functional cast expressions

    Example: Matches Foo(bar);
      Foo f = bar;
      Foo g = (Foo) bar;
      Foo h = Foo(bar);
Matcher<Stmt> | cxxMemberCallExpr | Matcher<CXXMemberCallExpr>...
    Matches member call expressions.

    Example matches x.y()
      X x;
      x.y();
Matcher<Stmt> | cxxNewExpr | Matcher<CXXNewExpr>...
    Matches new expressions.

    Given
      new X;
    cxxNewExpr()
      matches 'new X'.
Matcher<Stmt> | cxxNoexceptExpr | Matcher<CXXNoexceptExpr>...
    Matches noexcept expressions.

    Given
      bool a() noexcept;
      bool b() noexcept(true);
      bool c() noexcept(false);
      bool d() noexcept(noexcept(a()));
      bool e = noexcept(b()) || noexcept(c());
    cxxNoexceptExpr()
      matches `noexcept(a())`, `noexcept(b())` and `noexcept(c())`.
      doesn't match the noexcept specifier in the declarations a, b, c or d.
Matcher<Stmt> | cxxNullPtrLiteralExpr | Matcher<CXXNullPtrLiteralExpr>...
    Matches nullptr literal.
Matcher<Stmt> | cxxOperatorCallExpr | Matcher<CXXOperatorCallExpr>...
    Matches overloaded operator calls.

    Note that if an operator isn't overloaded, it won't match. Instead, use
    binaryOperator matcher.
    Currently it does not match operators such as new delete.
    FIXME: figure out why these do not match?

    Example matches both operator<<((o << b), c) and operator<<(o, b)
        (matcher = cxxOperatorCallExpr())
      ostream &operator<< (ostream &out, int i) { };
      ostream &o; int b = 1, c = 1;
      o << b << c;
    See also the binaryOperation() matcher for more-general matching of binary
    uses of this AST node.
Matcher<Stmt> | cxxReinterpretCastExpr | Matcher<CXXReinterpretCastExpr>...
    Matches a reinterpret_cast expression.

    Either the source expression or the destination type can be matched
    using has(), but hasDestinationType() is more specific and can be
    more readable.

    Example matches reinterpret_cast<char*>(&p) in
      void* p = reinterpret_cast<char*>(&p);
Matcher<Stmt> | cxxRewrittenBinaryOperator | Matcher<CXXRewrittenBinaryOperator>...
    Matches rewritten binary operators

    Example matches use of "<":
      #include <compare>
      struct HasSpaceshipMem {
        int a;
        constexpr auto operator<=>(const HasSpaceshipMem&) const = default;
      };
      void compare() {
        HasSpaceshipMem hs1, hs2;
        if (hs1 < hs2)
            return;
      }
    See also the binaryOperation() matcher for more-general matching
    of this AST node.
Matcher<Stmt> | cxxStaticCastExpr | Matcher<CXXStaticCastExpr>...
    Matches a C++ static_cast expression.

    See also: hasDestinationType
    See also: reinterpretCast

    Example:
      cxxStaticCastExpr()
    matches
      static_cast<long>(8)
    in
      long eight(static_cast<long>(8));
Matcher<Stmt> | cxxStdInitializerListExpr | Matcher<CXXStdInitializerListExpr>...
    Matches C++ initializer list expressions.

    Given
      std::vector<int> a({ 1, 2, 3 });
      std::vector<int> b = { 4, 5 };
      int c[] = { 6, 7 };
      std::pair<int, int> d = { 8, 9 };
    cxxStdInitializerListExpr()
      matches "{ 1, 2, 3 }" and "{ 4, 5 }"
Matcher<Stmt> | cxxTemporaryObjectExpr | Matcher<CXXTemporaryObjectExpr>...
    Matches functional cast expressions having N != 1 arguments

    Example: Matches Foo(bar, bar)
      Foo h = Foo(bar, bar);
Matcher<Stmt> | cxxThisExpr | Matcher<CXXThisExpr>...
    Matches implicit and explicit this expressions.

    Example matches the implicit this expression in "return i".
        (matcher = cxxThisExpr())
    struct foo {
      int i;
      int f() { return i; }
    };
Matcher<Stmt> | cxxThrowExpr | Matcher<CXXThrowExpr>...
    Matches throw expressions.

      try { throw 5; } catch(int i) {}
    cxxThrowExpr()
      matches 'throw 5'
Matcher<Stmt> | cxxTryStmt | Matcher<CXXTryStmt>...
    Matches try statements.

      try {} catch(int i) {}
    cxxTryStmt()
      matches 'try {}'
Matcher<Stmt> | cxxUnresolvedConstructExpr | Matcher<CXXUnresolvedConstructExpr>...
    Matches unresolved constructor call expressions.

    Example matches T(t) in return statement of f
        (matcher = cxxUnresolvedConstructExpr())
      template <typename T>
      void f(const T& t) { return T(t); }
Matcher<Stmt> | declRefExpr | Matcher<DeclRefExpr>...
    Matches expressions that refer to declarations.

    Example matches x in if (x)
      bool x;
      if (x) {}
Matcher<Stmt> | declStmt | Matcher<DeclStmt>...
    Matches declaration statements.

    Given
      int a;
    declStmt()
      matches 'int a'.
Matcher<Stmt> | defaultStmt | Matcher<DefaultStmt>...
    Matches default statements inside switch statements.

    Given
      switch(a) { case 42: break; default: break; }
    defaultStmt()
      matches 'default:'.
Matcher<Stmt> | designatedInitExpr | Matcher<DesignatedInitExpr>...
    Matches C99 designated initializer expressions [C99 6.7.8].

    Example: Matches { [2].y = 1.0, [0].x = 1.0 }
      point ptarray[10] = { [2].y = 1.0, [0].x = 1.0 };
Matcher<Stmt> | doStmt | Matcher<DoStmt>...
    Matches do statements.

    Given
      do {} while (true);
    doStmt()
      matches 'do {} while(true)'
Matcher<Stmt> | explicitCastExpr | Matcher<ExplicitCastExpr>...
    Matches explicit cast expressions.

    Matches any cast expression written in user code, whether it be a
    C-style cast, a functional-style cast, or a keyword cast.

    Does not match implicit conversions.

    Note: the name "explicitCast" is chosen to match Clang's terminology, as
    Clang uses the term "cast" to apply to implicit conversions as well as to
    actual cast expressions.

    See also: hasDestinationType.

    Example: matches all five of the casts in
      int((int)(reinterpret_cast<int>(static_cast<int>(const_cast<int>(42)))))
    but does not match the implicit conversion in
      long ell = 42;
Matcher<Stmt> | expr | Matcher<Expr>...
    Matches expressions.

    Example matches x()
      void f() { x(); }
Matcher<Stmt> | exprWithCleanups | Matcher<ExprWithCleanups>...
    Matches expressions that introduce cleanups to be run at the end
    of the sub-expression's evaluation.

    Example matches std::string()
      const std::string str = std::string();
Matcher<Stmt> | fixedPointLiteral | Matcher<FixedPointLiteral>...
    Matches fixed point literals
Matcher<Stmt> | floatLiteral | Matcher<FloatingLiteral>...
    Matches float literals of all sizes / encodings, e.g.
    1.0, 1.0f, 1.0L and 1e10.

    Does not match implicit conversions such as
      float a = 10;
Matcher<Stmt> | forStmt | Matcher<ForStmt>...
    Matches for statements.

    Example matches 'for (;;) {}'
      for (;;) {}
      int i[] =  {1, 2, 3}; for (auto a : i);
Matcher<Stmt> | genericSelectionExpr | Matcher<GenericSelectionExpr>...
    Matches C11 _Generic expression.
Matcher<Stmt> | gnuNullExpr | Matcher<GNUNullExpr>...
    Matches GNU __null expression.
Matcher<Stmt> | gotoStmt | Matcher<GotoStmt>...
    Matches goto statements.

    Given
      goto FOO;
      FOO: bar();
    gotoStmt()
      matches 'goto FOO'
Matcher<Stmt> | ifStmt | Matcher<IfStmt>...
    Matches if statements.

    Example matches 'if (x) {}'
      if (x) {}
Matcher<Stmt> | imaginaryLiteral | Matcher<ImaginaryLiteral>...
    Matches imaginary literals, which are based on integer and floating
    point literals e.g.: 1i, 1.0i
Matcher<Stmt> | implicitCastExpr | Matcher<ImplicitCastExpr>...
    Matches the implicit cast nodes of Clang's AST.

    This matches many different places, including function call return value
    eliding, as well as any type conversions.
Matcher<Stmt> | implicitValueInitExpr | Matcher<ImplicitValueInitExpr>...
    Matches implicit initializers of init list expressions.

    Given
      point ptarray[10] = { [2].y = 1.0, [2].x = 2.0, [0].x = 1.0 };
    implicitValueInitExpr()
      matches "[0].y" (implicitly)
Matcher<Stmt> | initListExpr | Matcher<InitListExpr>...
    Matches init list expressions.

    Given
      int a[] = { 1, 2 };
      struct B { int x, y; };
      B b = { 5, 6 };
    initListExpr()
      matches "{ 1, 2 }" and "{ 5, 6 }"
Matcher<Stmt> | integerLiteral | Matcher<IntegerLiteral>...
    Matches integer literals of all sizes / encodings, e.g.
    1, 1L, 0x1 and 1U.

    Does not match character-encoded integers such as L'a'.
Matcher<Stmt> | labelStmt | Matcher<LabelStmt>...
    Matches label statements.

    Given
      goto FOO;
      FOO: bar();
    labelStmt()
      matches 'FOO:'
Matcher<Stmt> | lambdaExpr | Matcher<LambdaExpr>...
    Matches lambda expressions.

    Example matches [&](){return 5;}
      [&](){return 5;}
Matcher<Stmt> | materializeTemporaryExpr | Matcher<MaterializeTemporaryExpr>...
    Matches nodes where temporaries are materialized.

    Example: Given
      struct T {void func();};
      T f();
      void g(T);
    materializeTemporaryExpr() matches 'f()' in these statements
      T u(f());
      g(f());
      f().func();
    but does not match
      f();
Matcher<Stmt> | memberExpr | Matcher<MemberExpr>...
    Matches member expressions.

    Given
      class Y {
        void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
        int a; static int b;
      };
    memberExpr()
      matches this->x, x, y.x, a, this->b
Matcher<Stmt> | nullStmt | Matcher<NullStmt>...
    Matches null statements.

      foo();;
    nullStmt()
      matches the second ';'
Matcher<Stmt> | objcCatchStmt | Matcher<ObjCAtCatchStmt>...
    Matches Objective-C @catch statements.

    Example matches @catch
      @try {}
      @catch (...) {}
Matcher<Stmt> | objcFinallyStmt | Matcher<ObjCAtFinallyStmt>...
    Matches Objective-C @finally statements.

    Example matches @finally
      @try {}
      @finally {}
Matcher<Stmt> | objcIvarRefExpr | Matcher<ObjCIvarRefExpr>...
    Matches a reference to an ObjCIvar.

    Example: matches "a" in "init" method:
    @implementation A {
      NSString *a;
    }
    - (void) init {
      a = @"hello";
    }
Matcher<Stmt> | objcMessageExpr | Matcher<ObjCMessageExpr>...
    Matches ObjectiveC Message invocation expressions.

    The innermost message send invokes the "alloc" class method on the
    NSString class, while the outermost message send invokes the
    "initWithString" instance method on the object returned from
    NSString's "alloc". This matcher should match both message sends.
      [[NSString alloc] initWithString:@"Hello"]
Matcher<Stmt> | objcThrowStmt | Matcher<ObjCAtThrowStmt>...
    Matches Objective-C statements.

    Example matches @throw obj;
Matcher<Stmt> | objcTryStmt | Matcher<ObjCAtTryStmt>...
    Matches Objective-C @try statements.

    Example matches @try
      @try {}
      @catch (...) {}
Matcher<Stmt> | ompExecutableDirective | Matcher<OMPExecutableDirective>...
    Matches any ``#pragma omp`` executable directive.

    Given

      #pragma omp parallel
      #pragma omp parallel default(none)
      #pragma omp taskyield

    ``ompExecutableDirective()`` matches ``omp parallel``,
    ``omp parallel default(none)`` and ``omp taskyield``.
Matcher<Stmt> | opaqueValueExpr | Matcher<OpaqueValueExpr>...
    Matches opaque value expressions. They are used as helpers
    to reference another expressions and can be met
    in BinaryConditionalOperators, for example.

    Example matches 'a'
      (a ?: c) + 42;
Matcher<Stmt> | parenExpr | Matcher<ParenExpr>...
    Matches parentheses used in expressions.

    Example matches (foo() + 1)
      int foo() { return 1; }
      int a = (foo() + 1);
Matcher<Stmt> | parenListExpr | Matcher<ParenListExpr>...
    Matches paren list expressions.
    ParenListExprs don't have a predefined type and are used for late parsing.
    In the final AST, they can be met in template declarations.

    Given
      template<typename T> class X {
        void f() {
          X x(*this);
          int a = 0, b = 1; int i = (a, b);
        }
      };
    parenListExpr() matches "*this" but NOT matches (a, b) because (a, b)
    has a predefined type and is a ParenExpr, not a ParenListExpr.
Matcher<Stmt> | predefinedExpr | Matcher<PredefinedExpr>...
    Matches predefined identifier expressions [C99 6.4.2.2].

    Example: Matches __func__
      printf("%s", __func__);
Matcher<Stmt> | returnStmt | Matcher<ReturnStmt>...
    Matches return statements.

    Given
      return 1;
    returnStmt()
      matches 'return 1'
Matcher<Stmt> | stmt | Matcher<Stmt>...
    Matches statements.

    Given
      { ++a; }
    stmt()
      matches both the compound statement '{ ++a; }' and '++a'.
Matcher<Stmt> | stmtExpr | Matcher<StmtExpr>...
    Matches statement expression (GNU extension).

    Example match: ({ int X = 4; X; })
      int C = ({ int X = 4; X; });
Matcher<Stmt> | stringLiteral | Matcher<StringLiteral>...
    Matches string literals (also matches wide string literals).

    Example matches "abcd", L"abcd"
      char *s = "abcd";
      wchar_t *ws = L"abcd";
Matcher<Stmt> | substNonTypeTemplateParmExpr | Matcher<SubstNonTypeTemplateParmExpr>...
    Matches substitutions of non-type template parameters.

    Given
      template <int N>
      struct A { static const int n = N; };
      struct B : public A<42> {};
    substNonTypeTemplateParmExpr()
      matches "N" in the right-hand side of "static const int n = N;"
Matcher<Stmt> | switchCase | Matcher<SwitchCase>...
    Matches case and default statements inside switch statements.

    Given
      switch(a) { case 42: break; default: break; }
    switchCase()
      matches 'case 42:' and 'default:'.
Matcher<Stmt> | switchStmt | Matcher<SwitchStmt>...
    Matches switch statements.

    Given
      switch(a) { case 42: break; default: break; }
    switchStmt()
      matches 'switch(a)'.
Matcher<Stmt> | unaryExprOrTypeTraitExpr | Matcher<UnaryExprOrTypeTraitExpr>...
    Matches sizeof (C99), alignof (C++11) and vec_step (OpenCL)

    Given
      Foo x = bar;
      int y = sizeof(x) + alignof(x);
    unaryExprOrTypeTraitExpr()
      matches sizeof(x) and alignof(x)
Matcher<Stmt> | unaryOperator | Matcher<UnaryOperator>...
    Matches unary operator expressions.

    Example matches !a
      !a || b
Matcher<Stmt> | unresolvedLookupExpr | Matcher<UnresolvedLookupExpr>...
    Matches reference to a name that can be looked up during parsing
    but could not be resolved to a specific declaration.

    Given
      template<typename T>
      T foo() { T a; return a; }
      template<typename T>
      void bar() {
        foo<T>();
      }
    unresolvedLookupExpr()
      matches foo<T>()
Matcher<Stmt> | unresolvedMemberExpr | Matcher<UnresolvedMemberExpr>...
    Matches unresolved member expressions.

    Given
      struct X {
        template <class T> void f();
        void g();
      };
      template <class T> void h() { X x; x.f<T>(); x.g(); }
    unresolvedMemberExpr()
      matches x.f<T>
Matcher<Stmt> | userDefinedLiteral | Matcher<UserDefinedLiteral>...
    Matches user defined literal operator call.

    Example match: "foo"_suffix
Matcher<Stmt> | whileStmt | Matcher<WhileStmt>...
    Matches while statements.

    Given
      while (true) {}
    whileStmt()
      matches 'while (true) {}'.
Matcher<TemplateArgumentLoc> | templateArgumentLoc | Matcher<TemplateArgumentLoc>...
    Matches template arguments (with location info).

    Given
      template <typename T> struct C {};
      C<int> c;
    templateArgumentLoc()
      matches 'int' in C<int>.
Matcher<TemplateArgument> | templateArgument | Matcher<TemplateArgument>...
    Matches template arguments.

    Given
      template <typename T> struct C {};
      C<int> c;
    templateArgument()
      matches 'int' in C<int>.
Matcher<TemplateName> | templateName | Matcher<TemplateName>...
    Matches template name.

    Given
      template <typename T> class X { };
      X<int> xi;
    templateName()
      matches 'X' in X<int>.
Matcher<TypeLoc> | typeLoc | Matcher<TypeLoc>...
    Matches TypeLocs in the clang AST.
Matcher<Type> | arrayType | Matcher<ArrayType>...
    Matches all kinds of arrays.

    Given
      int a[] = { 2, 3 };
      int b[4];
      void f() { int c[a[0]]; }
    arrayType()
      matches "int a[]", "int b[4]" and "int c[a[0]]";
Matcher<Type> | atomicType | Matcher<AtomicType>...
    Matches atomic types.

    Given
      _Atomic(int) i;
    atomicType()
      matches "_Atomic(int) i"
Matcher<Type> | autoType | Matcher<AutoType>...
    Matches types nodes representing C++11 auto types.

    Given:
      auto n = 4;
      int v[] = { 2, 3 }
      for (auto i : v) { }
    autoType()
      matches "auto n" and "auto i"
Matcher<Type> | blockPointerType | Matcher<BlockPointerType>...
    Matches block pointer types, i.e. types syntactically represented as
    "void (^)(int)".

    The pointee is always required to be a FunctionType.
Matcher<Type> | builtinType | Matcher<BuiltinType>...
    Matches builtin Types.

    Given
      struct A {};
      A a;
      int b;
      float c;
      bool d;
    builtinType()
      matches "int b", "float c" and "bool d"
Matcher<Type> | complexType | Matcher<ComplexType>...
    Matches C99 complex types.

    Given
      _Complex float f;
    complexType()
      matches "_Complex float f"
Matcher<Type> | constantArrayType | Matcher<ConstantArrayType>...
    Matches C arrays with a specified constant size.

    Given
      void() {
        int a[2];
        int b[] = { 2, 3 };
        int c[b[0]];
      }
    constantArrayType()
      matches "int a[2]"
Matcher<Type> | decayedType | Matcher<DecayedType>...
    Matches decayed type
    Example matches i[] in declaration of f.
        (matcher = valueDecl(hasType(decayedType(hasDecayedType(pointerType())))))
    Example matches i[1].
        (matcher = expr(hasType(decayedType(hasDecayedType(pointerType())))))
      void f(int i[]) {
        i[1] = 0;
      }
Matcher<Type> | decltypeType | Matcher<DecltypeType>...
    Matches types nodes representing C++11 decltype(<expr>) types.

    Given:
      short i = 1;
      int j = 42;
      decltype(i + j) result = i + j;
    decltypeType()
      matches "decltype(i + j)"
Matcher<Type> | deducedTemplateSpecializationType | Matcher<DeducedTemplateSpecializationType>...
    Matches C++17 deduced template specialization types, e.g. deduced class
    template types.

    Given
      template <typename T>
      class C { public: C(T); };

      C c(123);
    deducedTemplateSpecializationType() matches the type in the declaration
    of the variable c.
Matcher<Type> | dependentSizedArrayType | Matcher<DependentSizedArrayType>...
    Matches C++ arrays whose size is a value-dependent expression.

    Given
      template<typename T, int Size>
      class array {
        T data[Size];
      };
    dependentSizedArrayType
      matches "T data[Size]"
Matcher<Type> | elaboratedType | Matcher<ElaboratedType>...
    Matches types specified with an elaborated type keyword or with a
    qualified name.

    Given
      namespace N {
        namespace M {
          class D {};
        }
      }
      class C {};

      class C c;
      N::M::D d;

    elaboratedType() matches the type of the variable declarations of both
    c and d.
Matcher<Type> | enumType | Matcher<EnumType>...
    Matches enum types.

    Given
      enum C { Green };
      enum class S { Red };

      C c;
      S s;

    enumType() matches the type of the variable declarations of both c and
    s.
Matcher<Type> | functionProtoType | Matcher<FunctionProtoType>...
    Matches FunctionProtoType nodes.

    Given
      int (*f)(int);
      void g();
    functionProtoType()
      matches "int (*f)(int)" and the type of "g" in C++ mode.
      In C mode, "g" is not matched because it does not contain a prototype.
Matcher<Type> | functionType | Matcher<FunctionType>...
    Matches FunctionType nodes.

    Given
      int (*f)(int);
      void g();
    functionType()
      matches "int (*f)(int)" and the type of "g".
Matcher<Type> | incompleteArrayType | Matcher<IncompleteArrayType>...
    Matches C arrays with unspecified size.

    Given
      int a[] = { 2, 3 };
      int b[42];
      void f(int c[]) { int d[a[0]]; };
    incompleteArrayType()
      matches "int a[]" and "int c[]"
Matcher<Type> | injectedClassNameType | Matcher<InjectedClassNameType>...
    Matches injected class name types.

    Example matches S s, but not S<T> s.
        (matcher = parmVarDecl(hasType(injectedClassNameType())))
      template <typename T> struct S {
        void f(S s);
        void g(S<T> s);
      };
Matcher<Type> | lValueReferenceType | Matcher<LValueReferenceType>...
    Matches lvalue reference types.

    Given:
      int *a;
      int &b = *a;
      int &&c = 1;
      auto &d = b;
      auto &&e = c;
      auto &&f = 2;
      int g = 5;

    lValueReferenceType() matches the types of b, d, and e. e is
    matched since the type is deduced as int& by reference collapsing rules.
Matcher<Type> | memberPointerType | Matcher<MemberPointerType>...
    Matches member pointer types.
    Given
      struct A { int i; }
      A::* ptr = A::i;
    memberPointerType()
      matches "A::* ptr"
Matcher<Type> | objcObjectPointerType | Matcher<ObjCObjectPointerType>...
    Matches an Objective-C object pointer type, which is different from
    a pointer type, despite being syntactically similar.

    Given
      int *a;

      @interface Foo
      @end
      Foo *f;
    pointerType()
      matches "Foo *f", but does not match "int *a".
Matcher<Type> | parenType | Matcher<ParenType>...
    Matches ParenType nodes.

    Given
      int (*ptr_to_array)[4];
      int *array_of_ptrs[4];

    varDecl(hasType(pointsTo(parenType()))) matches ptr_to_array but not
    array_of_ptrs.
Matcher<Type> | pointerType | Matcher<PointerType>...
    Matches pointer types, but does not match Objective-C object pointer
    types.

    Given
      int *a;
      int &b = *a;
      int c = 5;

      @interface Foo
      @end
      Foo *f;
    pointerType()
      matches "int *a", but does not match "Foo *f".
Matcher<Type> | rValueReferenceType | Matcher<RValueReferenceType>...
    Matches rvalue reference types.

    Given:
      int *a;
      int &b = *a;
      int &&c = 1;
      auto &d = b;
      auto &&e = c;
      auto &&f = 2;
      int g = 5;

    rValueReferenceType() matches the types of c and f. e is not
    matched as it is deduced to int& by reference collapsing rules.
Matcher<Type> | recordType | Matcher<RecordType>...
    Matches record types (e.g. structs, classes).

    Given
      class C {};
      struct S {};

      C c;
      S s;

    recordType() matches the type of the variable declarations of both c
    and s.
Matcher<Type> | referenceType | Matcher<ReferenceType>...
    Matches both lvalue and rvalue reference types.

    Given
      int *a;
      int &b = *a;
      int &&c = 1;
      auto &d = b;
      auto &&e = c;
      auto &&f = 2;
      int g = 5;

    referenceType() matches the types of b, c, d, e, and f.
Matcher<Type> | substTemplateTypeParmType | Matcher<SubstTemplateTypeParmType>...
    Matches types that represent the result of substituting a type for a
    template type parameter.

    Given
      template <typename T>
      void F(T t) {
        int i = 1 + t;
      }

    substTemplateTypeParmType() matches the type of 't' but not '1'
Matcher<Type> | tagType | Matcher<TagType>...
    Matches tag types (record and enum types).

    Given
      enum E {};
      class C {};

      E e;
      C c;

    tagType() matches the type of the variable declarations of both e
    and c.
Matcher<Type> | templateSpecializationType | Matcher<TemplateSpecializationType>...
    Matches template specialization types.

    Given
      template <typename T>
      class C { };

      template class C<int>;  // A
      C<char> var;            // B

    templateSpecializationType() matches the type of the explicit
    instantiation in A and the type of the variable declaration in B.
Matcher<Type> | templateTypeParmType | Matcher<TemplateTypeParmType>...
    Matches template type parameter types.

    Example matches T, but not int.
        (matcher = templateTypeParmType())
      template <typename T> void f(int i);
Matcher<Type> | type | Matcher<Type>...
    Matches Types in the clang AST.
Matcher<Type> | typedefType | Matcher<TypedefType>...
    Matches typedef types.

    Given
      typedef int X;
    typedefType()
      matches "typedef int X"
Matcher<Type> | unaryTransformType | Matcher<UnaryTransformType>...
    Matches types nodes representing unary type transformations.

    Given:
      typedef __underlying_type(T) type;
    unaryTransformType()
      matches "__underlying_type(T)"
Matcher<Type> | variableArrayType | Matcher<VariableArrayType>...
    Matches C arrays with a specified size that is not an
    integer-constant-expression.

    Given
      void f() {
        int a[] = { 2, 3 }
        int b[42];
        int c[a[0]];
      }
    variableArrayType()
      matches "int c[a[0]]"

## Narrowing Matchers

Narrowing matchers match certain attributes on the current node, thus narrowing down the set of nodes of the current type to match on.

There are special logical narrowing matchers (allOf, anyOf, anything and unless) which allow users to create more powerful match expressions.

Return type | Name | Parameters
--- | --- | ---
Matcher<*> | allOf | Matcher<*>, ..., Matcher<*>
    Matches if all given matchers match.

    Usable as: Any Matcher
Matcher<*> | anyOf | Matcher<*>, ..., Matcher<*>
    Matches if any of the given matchers matches.

    Usable as: Any Matcher
Matcher<*> | anything |
    Matches any node.

    Useful when another matcher requires a child matcher, but there's no
    additional constraint. This will often be used with an explicit conversion
    to an internal::Matcher<> type such as TypeMatcher.

    Example: DeclarationMatcher(anything()) matches all declarations, e.g.,
    "int* p" and "void f()" in
      int* p;
      void f();

    Usable as: Any Matcher
unspecified | mapAnyOf | nodeMatcherFunction...
    Matches any of the NodeMatchers with InnerMatchers nested within

    Given
      if (true);
      for (; true; );
    with the matcher
      mapAnyOf(ifStmt, forStmt).with(
        hasCondition(cxxBoolLiteralExpr(equals(true)))
        ).bind("trueCond")
    matches the if and the for. It is equivalent to:
      auto trueCond = hasCondition(cxxBoolLiteralExpr(equals(true)));
      anyOf(
        ifStmt(trueCond).bind("trueCond"),
        forStmt(trueCond).bind("trueCond")
        );

    The with() chain-call accepts zero or more matchers which are combined
    as-if with allOf() in each of the node matchers.
    Usable as: Any Matcher
Matcher<*> | unless | Matcher<*>
    Matches if the provided matcher does not match.

    Example matches Y (matcher = cxxRecordDecl(unless(hasName("X"))))
      class X {};
      class Y {};

    Usable as: Any Matcher
Matcher<BinaryOperator> | hasAnyOperatorName | StringRef, ..., StringRef
    Matches operator expressions (binary or unary) that have any of the
    specified names.

       hasAnyOperatorName("+", "-")
     Is equivalent to
       anyOf(hasOperatorName("+"), hasOperatorName("-"))
Matcher<BinaryOperator> | hasOperatorName | std::string Name
    Matches the operator Name of operator expressions (binary or
    unary).

    Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
      !(a || b)
Matcher<BinaryOperator> | isAssignmentOperator |
    Matches all kinds of assignment operators.

    Example 1: matches a += b (matcher = binaryOperator(isAssignmentOperator()))
      if (a == b)
        a += b;

    Example 2: matches s1 = s2
               (matcher = cxxOperatorCallExpr(isAssignmentOperator()))
      struct S { S& operator=(const S&); };
      void x() { S s1, s2; s1 = s2; }
Matcher<BinaryOperator> | isComparisonOperator |
    Matches comparison operators.

    Example 1: matches a == b (matcher = binaryOperator(isComparisonOperator()))
      if (a == b)
        a += b;

    Example 2: matches s1 < s2
               (matcher = cxxOperatorCallExpr(isComparisonOperator()))
      struct S { bool operator<(const S& other); };
      void x(S s1, S s2) { bool b1 = s1 < s2; }
Matcher<CXXBaseSpecifier> | isPrivate |
    Matches private C++ declarations and C++ base specifers that specify private
    inheritance.

    Examples:
      class C {
      public:    int a;
      protected: int b;
      private:   int c; // fieldDecl(isPrivate()) matches 'c'
      };

      struct Base {};
      struct Derived1 : private Base {}; // matches 'Base'
      class Derived2 : Base {}; // matches 'Base'
Matcher<CXXBaseSpecifier> | isProtected |
    Matches protected C++ declarations and C++ base specifers that specify
    protected inheritance.

    Examples:
      class C {
      public:    int a;
      protected: int b; // fieldDecl(isProtected()) matches 'b'
      private:   int c;
      };

      class Base {};
      class Derived : protected Base {}; // matches 'Base'
Matcher<CXXBaseSpecifier> | isPublic |
    Matches public C++ declarations and C++ base specifers that specify public
    inheritance.

    Examples:
      class C {
      public:    int a; // fieldDecl(isPublic()) matches 'a'
      protected: int b;
      private:   int c;
      };

      class Base {};
      class Derived1 : public Base {}; // matches 'Base'
      struct Derived2 : Base {}; // matches 'Base'
Matcher<CXXBaseSpecifier> | isVirtual |
    Matches declarations of virtual methods and C++ base specifers that specify
    virtual inheritance.

    Example:
      class A {
       public:
        virtual void x(); // matches x
      };

    Example:
      class Base {};
      class DirectlyDerived : virtual Base {}; // matches Base
      class IndirectlyDerived : DirectlyDerived, Base {}; // matches Base

    Usable as: Matcher<CXXMethodDecl>, Matcher<CXXBaseSpecifier>
Matcher<CXXBoolLiteralExpr> | equals | bool Value
Matcher<CXXBoolLiteralExpr> | equals | const ValueT Value
    Matches literals that are equal to the given value of type ValueT.

    Given
      f('false, 3.14, 42);
    characterLiteral(equals(0))
      matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
      match false
    floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
      match 3.14
    integerLiteral(equals(42))
      matches 42

    Note that you cannot directly match a negative numeric literal because the
    minus sign is not part of the literal: It is a unary operator whose operand
    is the positive numeric literal. Instead, you must use a unaryOperator()
    matcher to match the minus sign:

    unaryOperator(hasOperatorName("-"),
                  hasUnaryOperand(integerLiteral(equals(13))))

    Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
               Matcher<FloatingLiteral>, Matcher<IntegerLiteral>
Matcher<CXXBoolLiteralExpr> | equals | double Value
Matcher<CXXBoolLiteralExpr> | equals | unsigned Value
Matcher<CXXCatchStmt> | isCatchAll |
    Matches a C++ catch statement that has a catch-all handler.

    Given
      try {
        // ...
      } catch (int) {
        // ...
      } catch (...) {
        // ...
      }
    cxxCatchStmt(isCatchAll()) matches catch(...) but not catch(int).
Matcher<CXXConstructExpr> | argumentCountIs | unsigned N
    Checks that a call expression or a constructor call expression has
    a specific number of arguments (including absent default arguments).

    Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
      void f(int x, int y);
      f(0, 0);
Matcher<CXXConstructExpr> | isListInitialization |
    Matches a constructor call expression which uses list initialization.
Matcher<CXXConstructExpr> | requiresZeroInitialization |
    Matches a constructor call expression which requires
    zero initialization.

    Given
    void foo() {
      struct point { double x; double y; };
      point pt[2] = { { 1.0, 2.0 } };
    }
    initListExpr(has(cxxConstructExpr(requiresZeroInitialization()))
    will match the implicit array filler for pt[1].
Matcher<CXXConstructorDecl> | isCopyConstructor |
    Matches constructor declarations that are copy constructors.

    Given
      struct S {
        S(); // #1
        S(const S &); // #2
        S(S &&); // #3
      };
    cxxConstructorDecl(isCopyConstructor()) will match #2, but not #1 or #3.
Matcher<CXXConstructorDecl> | isDefaultConstructor |
    Matches constructor declarations that are default constructors.

    Given
      struct S {
        S(); // #1
        S(const S &); // #2
        S(S &&); // #3
      };
    cxxConstructorDecl(isDefaultConstructor()) will match #1, but not #2 or #3.
Matcher<CXXConstructorDecl> | isDelegatingConstructor |
    Matches constructors that delegate to another constructor.

    Given
      struct S {
        S(); // #1
        S(int) {} // #2
        S(S &&) : S() {} // #3
      };
      S::S() : S(0) {} // #4
    cxxConstructorDecl(isDelegatingConstructor()) will match #3 and #4, but not
    #1 or #2.
Matcher<CXXConstructorDecl> | isExplicit |
    Matches constructor, conversion function, and deduction guide declarations
    that have an explicit specifier if this explicit specifier is resolved to
    true.

    Given
      template<bool b>
      struct S {
        S(int); // #1
        explicit S(double); // #2
        operator int(); // #3
        explicit operator bool(); // #4
        explicit(false) S(bool) // # 7
        explicit(true) S(char) // # 8
        explicit(b) S(S) // # 9
      };
      S(int) -> S<true> // #5
      explicit S(double) -> S<false> // #6
    cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
    cxxConversionDecl(isExplicit()) will match #4, but not #3.
    cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.
Matcher<CXXConstructorDecl> | isMoveConstructor |
    Matches constructor declarations that are move constructors.

    Given
      struct S {
        S(); // #1
        S(const S &); // #2
        S(S &&); // #3
      };
    cxxConstructorDecl(isMoveConstructor()) will match #3, but not #1 or #2.
Matcher<CXXConversionDecl> | isExplicit |
    Matches constructor, conversion function, and deduction guide declarations
    that have an explicit specifier if this explicit specifier is resolved to
    true.

    Given
      template<bool b>
      struct S {
        S(int); // #1
        explicit S(double); // #2
        operator int(); // #3
        explicit operator bool(); // #4
        explicit(false) S(bool) // # 7
        explicit(true) S(char) // # 8
        explicit(b) S(S) // # 9
      };
      S(int) -> S<true> // #5
      explicit S(double) -> S<false> // #6
    cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
    cxxConversionDecl(isExplicit()) will match #4, but not #3.
    cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.
Matcher<CXXCtorInitializer> | isBaseInitializer |
    Matches a constructor initializer if it is initializing a base, as
    opposed to a member.

    Given
      struct B {};
      struct D : B {
        int I;
        D(int i) : I(i) {}
      };
      struct E : B {
        E() : B() {}
      };
    cxxConstructorDecl(hasAnyConstructorInitializer(isBaseInitializer()))
      will match E(), but not match D(int).
Matcher<CXXCtorInitializer> | isMemberInitializer |
    Matches a constructor initializer if it is initializing a member, as
    opposed to a base.

    Given
      struct B {};
      struct D : B {
        int I;
        D(int i) : I(i) {}
      };
      struct E : B {
        E() : B() {}
      };
    cxxConstructorDecl(hasAnyConstructorInitializer(isMemberInitializer()))
      will match D(int), but not match E().
Matcher<CXXCtorInitializer> | isWritten |
    Matches a constructor initializer if it is explicitly written in
    code (as opposed to implicitly added by the compiler).

    Given
      struct Foo {
        Foo() { }
        Foo(int) : foo_("A") { }
        string foo_;
      };
    cxxConstructorDecl(hasAnyConstructorInitializer(isWritten()))
      will match Foo(int), but not Foo()
Matcher<CXXDeductionGuideDecl> | isExplicit |
    Matches constructor, conversion function, and deduction guide declarations
    that have an explicit specifier if this explicit specifier is resolved to
    true.

    Given
      template<bool b>
      struct S {
        S(int); // #1
        explicit S(double); // #2
        operator int(); // #3
        explicit operator bool(); // #4
        explicit(false) S(bool) // # 7
        explicit(true) S(char) // # 8
        explicit(b) S(S) // # 9
      };
      S(int) -> S<true> // #5
      explicit S(double) -> S<false> // #6
    cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
    cxxConversionDecl(isExplicit()) will match #4, but not #3.
    cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.
Matcher<CXXDependentScopeMemberExpr> | hasMemberName | std::string N
    Matches template-dependent, but known, member names.

    In template declarations, dependent members are not resolved and so can
    not be matched to particular named declarations.

    This matcher allows to match on the known name of members.

    Given
      template <typename T>
      struct S {
          void mem();
      };
      template <typename T>
      void x() {
          S<T> s;
          s.mem();
      }
    cxxDependentScopeMemberExpr(hasMemberName("mem")) matches `s.mem()`
Matcher<CXXDependentScopeMemberExpr> | isArrow |
    Matches member expressions that are called with '->' as opposed
    to '.'.

    Member calls on the implicit this pointer match as called with '->'.

    Given
      class Y {
        void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
        template <class T> void f() { this->f<T>(); f<T>(); }
        int a;
        static int b;
      };
      template <class T>
      class Z {
        void x() { this->m; }
      };
    memberExpr(isArrow())
      matches this->x, x, y.x, a, this->b
    cxxDependentScopeMemberExpr(isArrow())
      matches this->m
    unresolvedMemberExpr(isArrow())
      matches this->f<T>, f<T>
Matcher<CXXDependentScopeMemberExpr> | memberHasSameNameAsBoundNode | std::string BindingID
    Matches template-dependent, but known, member names against an already-bound
    node

    In template declarations, dependent members are not resolved and so can
    not be matched to particular named declarations.

    This matcher allows to match on the name of already-bound VarDecl, FieldDecl
    and CXXMethodDecl nodes.

    Given
      template <typename T>
      struct S {
          void mem();
      };
      template <typename T>
      void x() {
          S<T> s;
          s.mem();
      }
    The matcher
    @code
    cxxDependentScopeMemberExpr(
      hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
          hasDeclaration(classTemplateDecl(has(cxxRecordDecl(has(
              cxxMethodDecl(hasName("mem")).bind("templMem")
              )))))
          )))),
      memberHasSameNameAsBoundNode("templMem")
      )
    @endcode
    first matches and binds the @c mem member of the @c S template, then
    compares its name to the usage in @c s.mem() in the @c x function template
Matcher<CXXMethodDecl> | isConst |
    Matches if the given method declaration is const.

    Given
    struct A {
      void foo() const;
      void bar();
    };

    cxxMethodDecl(isConst()) matches A::foo() but not A::bar()
Matcher<CXXMethodDecl> | isCopyAssignmentOperator |
    Matches if the given method declaration declares a copy assignment
    operator.

    Given
    struct A {
      A &operator=(const A &);
      A &operator=(A &&);
    };

    cxxMethodDecl(isCopyAssignmentOperator()) matches the first method but not
    the second one.
Matcher<CXXMethodDecl> | isFinal |
    Matches if the given method or class declaration is final.

    Given:
      class A final {};

      struct B {
        virtual void f();
      };

      struct C : B {
        void f() final;
      };
    matches A and C::f, but not B, C, or B::f
Matcher<CXXMethodDecl> | isMoveAssignmentOperator |
    Matches if the given method declaration declares a move assignment
    operator.

    Given
    struct A {
      A &operator=(const A &);
      A &operator=(A &&);
    };

    cxxMethodDecl(isMoveAssignmentOperator()) matches the second method but not
    the first one.
Matcher<CXXMethodDecl> | isOverride |
    Matches if the given method declaration overrides another method.

    Given
      class A {
       public:
        virtual void x();
      };
      class B : public A {
       public:
        virtual void x();
      };
      matches B::x
Matcher<CXXMethodDecl> | isPure |
    Matches if the given method declaration is pure.

    Given
      class A {
       public:
        virtual void x() = 0;
      };
      matches A::x
Matcher<CXXMethodDecl> | isUserProvided |
    Matches method declarations that are user-provided.

    Given
      struct S {
        S(); // #1
        S(const S &) = default; // #2
        S(S &&) = delete; // #3
      };
    cxxConstructorDecl(isUserProvided()) will match #1, but not #2 or #3.
Matcher<CXXMethodDecl> | isVirtual |
    Matches declarations of virtual methods and C++ base specifers that specify
    virtual inheritance.

    Example:
      class A {
       public:
        virtual void x(); // matches x
      };

    Example:
      class Base {};
      class DirectlyDerived : virtual Base {}; // matches Base
      class IndirectlyDerived : DirectlyDerived, Base {}; // matches Base

    Usable as: Matcher<CXXMethodDecl>, Matcher<CXXBaseSpecifier>
Matcher<CXXMethodDecl> | isVirtualAsWritten |
    Matches if the given method declaration has an explicit "virtual".

    Given
      class A {
       public:
        virtual void x();
      };
      class B : public A {
       public:
        void x();
      };
      matches A::x but not B::x
Matcher<CXXNewExpr> | isArray |
    Matches array new expressions.

    Given:
      MyClass *p1 = new MyClass[10];
    cxxNewExpr(isArray())
      matches the expression 'new MyClass[10]'.
Matcher<CXXOperatorCallExpr> | hasAnyOperatorName | StringRef, ..., StringRef
    Matches operator expressions (binary or unary) that have any of the
    specified names.

       hasAnyOperatorName("+", "-")
     Is equivalent to
       anyOf(hasOperatorName("+"), hasOperatorName("-"))
Matcher<CXXOperatorCallExpr> | hasAnyOverloadedOperatorName | StringRef, ..., StringRef
    Matches overloaded operator names.

    Matches overloaded operator names specified in strings without the
    "operator" prefix: e.g. "<<".

      hasAnyOverloadedOperatorName("+", "-")
    Is equivalent to
      anyOf(hasOverloadedOperatorName("+"), hasOverloadedOperatorName("-"))
Matcher<CXXOperatorCallExpr> | hasOperatorName | std::string Name
    Matches the operator Name of operator expressions (binary or
    unary).

    Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
      !(a || b)
Matcher<CXXOperatorCallExpr> | hasOverloadedOperatorName | StringRef Name
    Matches overloaded operator names.

    Matches overloaded operator names specified in strings without the
    "operator" prefix: e.g. "<<".

    Given:
      class A { int operator*(); };
      const A &operator<<(const A &a, const A &b);
      A a;
      a << a;   // <-- This matches

    cxxOperatorCallExpr(hasOverloadedOperatorName("<<"))) matches the
    specified line and
    cxxRecordDecl(hasMethod(hasOverloadedOperatorName("*")))
    matches the declaration of A.

    Usable as: Matcher<CXXOperatorCallExpr>, Matcher<FunctionDecl>
Matcher<CXXOperatorCallExpr> | isAssignmentOperator |
    Matches all kinds of assignment operators.

    Example 1: matches a += b (matcher = binaryOperator(isAssignmentOperator()))
      if (a == b)
        a += b;

    Example 2: matches s1 = s2
               (matcher = cxxOperatorCallExpr(isAssignmentOperator()))
      struct S { S& operator=(const S&); };
      void x() { S s1, s2; s1 = s2; }
Matcher<CXXOperatorCallExpr> | isComparisonOperator |
    Matches comparison operators.

    Example 1: matches a == b (matcher = binaryOperator(isComparisonOperator()))
      if (a == b)
        a += b;

    Example 2: matches s1 < s2
               (matcher = cxxOperatorCallExpr(isComparisonOperator()))
      struct S { bool operator<(const S& other); };
      void x(S s1, S s2) { bool b1 = s1 < s2; }
Matcher<CXXRecordDecl> | hasDefinition |
    Matches a class declaration that is defined.

    Example matches x (matcher = cxxRecordDecl(hasDefinition()))
    class x {};
    class y;
Matcher<CXXRecordDecl> | isDerivedFrom | std::string BaseName
    Overloaded method as shortcut for isDerivedFrom(hasName(...)).
Matcher<CXXRecordDecl> | isDirectlyDerivedFrom | std::string BaseName
    Overloaded method as shortcut for isDirectlyDerivedFrom(hasName(...)).
Matcher<CXXRecordDecl> | isExplicitTemplateSpecialization |
    Matches explicit template specializations of function, class, or
    static member variable template instantiations.

    Given
      template<typename T> void A(T t) { }
      template<> void A(int N) { }
    functionDecl(isExplicitTemplateSpecialization())
      matches the specialization A<int>().

    Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>
Matcher<CXXRecordDecl> | isFinal |
    Matches if the given method or class declaration is final.

    Given:
      class A final {};

      struct B {
        virtual void f();
      };

      struct C : B {
        void f() final;
      };
    matches A and C::f, but not B, C, or B::f
Matcher<CXXRecordDecl> | isLambda |
    Matches the generated class of lambda expressions.

    Given:
      auto x = []{};

    cxxRecordDecl(isLambda()) matches the implicit class declaration of
    decltype(x)
Matcher<CXXRecordDecl> | isSameOrDerivedFrom | std::string BaseName
    Overloaded method as shortcut for
    isSameOrDerivedFrom(hasName(...)).
Matcher<CXXRecordDecl> | isTemplateInstantiation |
    Matches template instantiations of function, class, or static
    member variable template instantiations.

    Given
      template <typename T> class X {}; class A {}; X<A> x;
    or
      template <typename T> class X {}; class A {}; template class X<A>;
    or
      template <typename T> class X {}; class A {}; extern template class X<A>;
    cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
      matches the template instantiation of X<A>.

    But given
      template <typename T>  class X {}; class A {};
      template <> class X<A> {}; X<A> x;
    cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
      does not match, as X<A> is an explicit template specialization.

    Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>
Matcher<CXXRewrittenBinaryOperator> | hasAnyOperatorName | StringRef, ..., StringRef
    Matches operator expressions (binary or unary) that have any of the
    specified names.

       hasAnyOperatorName("+", "-")
     Is equivalent to
       anyOf(hasOperatorName("+"), hasOperatorName("-"))
Matcher<CXXRewrittenBinaryOperator> | hasOperatorName | std::string Name
    Matches the operator Name of operator expressions (binary or
    unary).

    Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
      !(a || b)
Matcher<CXXRewrittenBinaryOperator> | isAssignmentOperator |
    Matches all kinds of assignment operators.

    Example 1: matches a += b (matcher = binaryOperator(isAssignmentOperator()))
      if (a == b)
        a += b;

    Example 2: matches s1 = s2
               (matcher = cxxOperatorCallExpr(isAssignmentOperator()))
      struct S { S& operator=(const S&); };
      void x() { S s1, s2; s1 = s2; }
Matcher<CXXRewrittenBinaryOperator> | isComparisonOperator |
    Matches comparison operators.

    Example 1: matches a == b (matcher = binaryOperator(isComparisonOperator()))
      if (a == b)
        a += b;

    Example 2: matches s1 < s2
               (matcher = cxxOperatorCallExpr(isComparisonOperator()))
      struct S { bool operator<(const S& other); };
      void x(S s1, S s2) { bool b1 = s1 < s2; }
Matcher<CXXUnresolvedConstructExpr> | argumentCountIs | unsigned N
    Checks that a call expression or a constructor call expression has
    a specific number of arguments (including absent default arguments).

    Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
      void f(int x, int y);
      f(0, 0);
Matcher<CallExpr> | argumentCountIs | unsigned N
    Checks that a call expression or a constructor call expression has
    a specific number of arguments (including absent default arguments).

    Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
      void f(int x, int y);
      f(0, 0);
Matcher<CallExpr> | usesADL |
    Matches call expressions which were resolved using ADL.

    Example matches y(x) but not y(42) or NS::y(x).
      namespace NS {
        struct X {};
        void y(X);
      }

      void y(...);

      void test() {
        NS::X x;
        y(x); // Matches
        NS::y(x); // Doesn't match
        y(42); // Doesn't match
        using NS::y;
        y(x); // Found by both unqualified lookup and ADL, doesn't match
       }
Matcher<CastExpr> | hasCastKind | CastKind Kind
    Matches casts that has a given cast kind.

    Example: matches the implicit cast around 0
    (matcher = castExpr(hasCastKind(CK_NullToPointer)))
      int *p = 0;

    If the matcher is use from clang-query, CastKind parameter
    should be passed as a quoted string. e.g., hasCastKind("CK_NullToPointer").
Matcher<CharacterLiteral> | equals | bool Value
Matcher<CharacterLiteral> | equals | const ValueT Value
    Matches literals that are equal to the given value of type ValueT.

    Given
      f('false, 3.14, 42);
    characterLiteral(equals(0))
      matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
      match false
    floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
      match 3.14
    integerLiteral(equals(42))
      matches 42

    Note that you cannot directly match a negative numeric literal because the
    minus sign is not part of the literal: It is a unary operator whose operand
    is the positive numeric literal. Instead, you must use a unaryOperator()
    matcher to match the minus sign:

    unaryOperator(hasOperatorName("-"),
                  hasUnaryOperand(integerLiteral(equals(13))))

    Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
               Matcher<FloatingLiteral>, Matcher<IntegerLiteral>
Matcher<CharacterLiteral> | equals | double Value
Matcher<CharacterLiteral> | equals | unsigned Value
Matcher<ClassTemplateSpecializationDecl> | templateArgumentCountIs | unsigned N
    Matches if the number of template arguments equals N.

    Given
      template<typename T> struct C {};
      C<int> c;
    classTemplateSpecializationDecl(templateArgumentCountIs(1))
      matches C<int>.
Matcher<CompoundStmt> | statementCountIs | unsigned N
    Checks that a compound statement contains a specific number of
    child statements.

    Example: Given
      { for (;;) {} }
    compoundStmt(statementCountIs(0)))
      matches '{}'
      but does not match the outer compound statement.
Matcher<ConstantArrayType> | hasSize | unsigned N
    Matches nodes that have the specified size.

    Given
      int a[42];
      int b[2 * 21];
      int c[41], d[43];
      char *s = "abcd";
      wchar_t *ws = L"abcd";
      char *w = "a";
    constantArrayType(hasSize(42))
      matches "int a[42]" and "int b[2 * 21]"
    stringLiteral(hasSize(4))
      matches "abcd", L"abcd"
Matcher<DeclStmt> | declCountIs | unsigned N
    Matches declaration statements that contain a specific number of
    declarations.

    Example: Given
      int a, b;
      int c;
      int d = 2, e;
    declCountIs(2)
      matches 'int a, b;' and 'int d = 2, e;', but not 'int c;'.
Matcher<Decl> | equalsBoundNode | std::string ID
    Matches if a node equals a previously bound node.

    Matches a node if it equals the node previously bound to ID.

    Given
      class X { int a; int b; };
    cxxRecordDecl(
        has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
        has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
      matches the class X, as a and b have the same type.

    Note that when multiple matches are involved via forEach* matchers,
    equalsBoundNodes acts as a filter.
    For example:
    compoundStmt(
        forEachDescendant(varDecl().bind("d")),
        forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
    will trigger a match for each combination of variable declaration
    and reference to that variable declaration within a compound statement.
Matcher<Decl> | equalsNode | const Decl* Other
    Matches if a node equals another node.

    Decl has pointer identity in the AST.
Matcher<Decl> | hasAttr | attr::Kind AttrKind
    Matches declaration that has a given attribute.

    Given
      __attribute__((device)) void f() { ... }
    decl(hasAttr(clang::attr::CUDADevice)) matches the function declaration of
    f. If the matcher is used from clang-query, attr::Kind parameter should be
    passed as a quoted string. e.g., hasAttr("attr::CUDADevice").
Matcher<Decl> | isExpandedFromMacro | std::string MacroName
    Matches statements that are (transitively) expanded from the named macro.
    Does not match if only part of the statement is expanded from that macro or
    if different parts of the the statement are expanded from different
    appearances of the macro.
Matcher<Decl> | isExpansionInFileMatching | StringRef RegExp, Regex::RegexFlags Flags = NoFlags
    Matches AST nodes that were expanded within files whose name is
    partially matching a given regex.

    Example matches Y but not X
        (matcher = cxxRecordDecl(isExpansionInFileMatching("AST.*"))
      #include "ASTMatcher.h"
      class X {};
    ASTMatcher.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

    If the matcher is used in clang-query, RegexFlags parameter
    should be passed as a quoted string. e.g: "NoFlags".
    Flags can be combined with '|' example "IgnoreCase | BasicRegex"
Matcher<Decl> | isExpansionInMainFile |
    Matches AST nodes that were expanded within the main-file.

    Example matches X but not Y
      (matcher = cxxRecordDecl(isExpansionInMainFile())
      #include <Y.h>
      class X {};
    Y.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>
Matcher<Decl> | isExpansionInSystemHeader |
    Matches AST nodes that were expanded within system-header-files.

    Example matches Y but not X
        (matcher = cxxRecordDecl(isExpansionInSystemHeader())
      #include <SystemHeader.h>
      class X {};
    SystemHeader.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>
Matcher<Decl> | isImplicit |
    Matches a declaration that has been implicitly added
    by the compiler (eg. implicit default/copy constructors).
Matcher<Decl> | isInStdNamespace |
    Matches declarations in the namespace `std`, but not in nested namespaces.

    Given
      class vector {};
      namespace foo {
        class vector {};
        namespace std {
          class vector {};
        }
      }
      namespace std {
        inline namespace __1 {
          class vector {}; // #1
          namespace experimental {
            class vector {};
          }
        }
      }
    cxxRecordDecl(hasName("vector"), isInStdNamespace()) will match only #1.
Matcher<Decl> | isInstantiated |
    Matches declarations that are template instantiations or are inside
    template instantiations.

    Given
      template<typename T> void A(T t) { T i; }
      A(0);
      A(0U);
    functionDecl(isInstantiated())
      matches 'A(int) {...};' and 'A(unsigned) {...}'.
Matcher<Decl> | isPrivate |
    Matches private C++ declarations and C++ base specifers that specify private
    inheritance.

    Examples:
      class C {
      public:    int a;
      protected: int b;
      private:   int c; // fieldDecl(isPrivate()) matches 'c'
      };

      struct Base {};
      struct Derived1 : private Base {}; // matches 'Base'
      class Derived2 : Base {}; // matches 'Base'
Matcher<Decl> | isProtected |
    Matches protected C++ declarations and C++ base specifers that specify
    protected inheritance.

    Examples:
      class C {
      public:    int a;
      protected: int b; // fieldDecl(isProtected()) matches 'b'
      private:   int c;
      };

      class Base {};
      class Derived : protected Base {}; // matches 'Base'
Matcher<Decl> | isPublic |
    Matches public C++ declarations and C++ base specifers that specify public
    inheritance.

    Examples:
      class C {
      public:    int a; // fieldDecl(isPublic()) matches 'a'
      protected: int b;
      private:   int c;
      };

      class Base {};
      class Derived1 : public Base {}; // matches 'Base'
      struct Derived2 : Base {}; // matches 'Base'
Matcher<DesignatedInitExpr> | designatorCountIs | unsigned N
    Matches designated initializer expressions that contain
    a specific number of designators.

    Example: Given
      point ptarray[10] = { [2].y = 1.0, [0].x = 1.0 };
      point ptarray2[10] = { [2].y = 1.0, [2].x = 0.0, [0].x = 1.0 };
    designatorCountIs(2)
      matches '{ [2].y = 1.0, [0].x = 1.0 }',
      but not '{ [2].y = 1.0, [2].x = 0.0, [0].x = 1.0 }'.
Matcher<EnumDecl> | isScoped |
    Matches C++11 scoped enum declaration.

    Example matches Y (matcher = enumDecl(isScoped()))
    enum X {};
    enum class Y {};
Matcher<Expr> | isInstantiationDependent |
    Matches expressions that are instantiation-dependent even if it is
    neither type- nor value-dependent.

    In the following example, the expression sizeof(sizeof(T() + T()))
    is instantiation-dependent (since it involves a template parameter T),
    but is neither type- nor value-dependent, since the type of the inner
    sizeof is known (std::size_t) and therefore the size of the outer
    sizeof is known.
      template<typename T>
      void f(T x, T y) { sizeof(sizeof(T() + T()); }
    expr(isInstantiationDependent()) matches sizeof(sizeof(T() + T())
Matcher<Expr> | isTypeDependent |
    Matches expressions that are type-dependent because the template type
    is not yet instantiated.

    For example, the expressions "x" and "x + y" are type-dependent in
    the following code, but "y" is not type-dependent:
      template<typename T>
      void add(T x, int y) {
        x + y;
      }
    expr(isTypeDependent()) matches x + y
Matcher<Expr> | isValueDependent |
    Matches expression that are value-dependent because they contain a
    non-type template parameter.

    For example, the array bound of "Chars" in the following example is
    value-dependent.
      template<int Size> int f() { return Size; }
    expr(isValueDependent()) matches return Size
Matcher<Expr> | nullPointerConstant |
    Matches expressions that resolve to a null pointer constant, such as
    GNU's __null, C++11's nullptr, or C's NULL macro.

    Given:
      void *v1 = NULL;
      void *v2 = nullptr;
      void *v3 = __null; // GNU extension
      char *cp = (char *)0;
      int *ip = 0;
      int i = 0;
    expr(nullPointerConstant())
      matches the initializer for v1, v2, v3, cp, and ip. Does not match the
      initializer for i.
Matcher<FieldDecl> | hasBitWidth | unsigned Width
    Matches non-static data members that are bit-fields of the specified
    bit width.

    Given
      class C {
        int a : 2;
        int b : 4;
        int c : 2;
      };
    fieldDecl(hasBitWidth(2))
      matches 'int a;' and 'int c;' but not 'int b;'.
Matcher<FieldDecl> | isBitField |
    Matches non-static data members that are bit-fields.

    Given
      class C {
        int a : 2;
        int b;
      };
    fieldDecl(isBitField())
      matches 'int a;' but not 'int b;'.
Matcher<FloatingLiteral> | equals | const ValueT Value
    Matches literals that are equal to the given value of type ValueT.

    Given
      f('false, 3.14, 42);
    characterLiteral(equals(0))
      matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
      match false
    floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
      match 3.14
    integerLiteral(equals(42))
      matches 42

    Note that you cannot directly match a negative numeric literal because the
    minus sign is not part of the literal: It is a unary operator whose operand
    is the positive numeric literal. Instead, you must use a unaryOperator()
    matcher to match the minus sign:

    unaryOperator(hasOperatorName("-"),
                  hasUnaryOperand(integerLiteral(equals(13))))

    Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
               Matcher<FloatingLiteral>, Matcher<IntegerLiteral>
Matcher<FloatingLiteral> | equals | double Value
Matcher<FunctionDecl> | hasAnyOverloadedOperatorName | StringRef, ..., StringRef
    Matches overloaded operator names.

    Matches overloaded operator names specified in strings without the
    "operator" prefix: e.g. "<<".

      hasAnyOverloadedOperatorName("+", "-")
    Is equivalent to
      anyOf(hasOverloadedOperatorName("+"), hasOverloadedOperatorName("-"))
Matcher<FunctionDecl> | hasDynamicExceptionSpec |
    Matches functions that have a dynamic exception specification.

    Given:
      void f();
      void g() noexcept;
      void h() noexcept(true);
      void i() noexcept(false);
      void j() throw();
      void k() throw(int);
      void l() throw(...);
    functionDecl(hasDynamicExceptionSpec()) and
      functionProtoType(hasDynamicExceptionSpec())
      match the declarations of j, k, and l, but not f, g, h, or i.
Matcher<FunctionDecl> | hasOverloadedOperatorName | StringRef Name
    Matches overloaded operator names.

    Matches overloaded operator names specified in strings without the
    "operator" prefix: e.g. "<<".

    Given:
      class A { int operator*(); };
      const A &operator<<(const A &a, const A &b);
      A a;
      a << a;   // <-- This matches

    cxxOperatorCallExpr(hasOverloadedOperatorName("<<"))) matches the
    specified line and
    cxxRecordDecl(hasMethod(hasOverloadedOperatorName("*")))
    matches the declaration of A.

    Usable as: Matcher<CXXOperatorCallExpr>, Matcher<FunctionDecl>
Matcher<FunctionDecl> | hasTrailingReturn |
    Matches a function declared with a trailing return type.

    Example matches Y (matcher = functionDecl(hasTrailingReturn()))
    int X() {}
    auto Y() -> int {}
Matcher<FunctionDecl> | isConstexpr |
    Matches constexpr variable and function declarations,
           and if constexpr.

    Given:
      constexpr int foo = 42;
      constexpr int bar();
      void baz() { if constexpr(1 > 0) {} }
    varDecl(isConstexpr())
      matches the declaration of foo.
    functionDecl(isConstexpr())
      matches the declaration of bar.
    ifStmt(isConstexpr())
      matches the if statement in baz.
Matcher<FunctionDecl> | isDefaulted |
    Matches defaulted function declarations.

    Given:
      class A { ~A(); };
      class B { ~B() = default; };
    functionDecl(isDefaulted())
      matches the declaration of ~B, but not ~A.
Matcher<FunctionDecl> | isDefinition |
    Matches if a declaration has a body attached.

    Example matches A, va, fa
      class A {};
      class B;  // Doesn't match, as it has no body.
      int va;
      extern int vb;  // Doesn't match, as it doesn't define the variable.
      void fa() {}
      void fb();  // Doesn't match, as it has no body.
      @interface X
      - (void)ma; // Doesn't match, interface is declaration.
      @end
      @implementation X
      - (void)ma {}
      @end

    Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
      Matcher<ObjCMethodDecl>
Matcher<FunctionDecl> | isDeleted |
    Matches deleted function declarations.

    Given:
      void Func();
      void DeletedFunc() = delete;
    functionDecl(isDeleted())
      matches the declaration of DeletedFunc, but not Func.
Matcher<FunctionDecl> | isExplicitTemplateSpecialization |
    Matches explicit template specializations of function, class, or
    static member variable template instantiations.

    Given
      template<typename T> void A(T t) { }
      template<> void A(int N) { }
    functionDecl(isExplicitTemplateSpecialization())
      matches the specialization A<int>().

    Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>
Matcher<FunctionDecl> | isExternC |
    Matches extern "C" function or variable declarations.

    Given:
      extern "C" void f() {}
      extern "C" { void g() {} }
      void h() {}
      extern "C" int x = 1;
      extern "C" int y = 2;
      int z = 3;
    functionDecl(isExternC())
      matches the declaration of f and g, but not the declaration of h.
    varDecl(isExternC())
      matches the declaration of x and y, but not the declaration of z.
Matcher<FunctionDecl> | isInline |
    Matches function and namespace declarations that are marked with
    the inline keyword.

    Given
      inline void f();
      void g();
      namespace n {
      inline namespace m {}
      }
    functionDecl(isInline()) will match ::f().
    namespaceDecl(isInline()) will match n::m.
Matcher<FunctionDecl> | isMain |
    Determines whether the function is "main", which is the entry point
    into an executable program.
Matcher<FunctionDecl> | isNoReturn |
    Matches FunctionDecls that have a noreturn attribute.

    Given
      void nope();
      [[noreturn]] void a();
      __attribute__((noreturn)) void b();
      struct c { [[noreturn]] c(); };
    functionDecl(isNoReturn())
      matches all of those except
      void nope();
Matcher<FunctionDecl> | isNoThrow |
    Matches functions that have a non-throwing exception specification.

    Given:
      void f();
      void g() noexcept;
      void h() throw();
      void i() throw(int);
      void j() noexcept(false);
    functionDecl(isNoThrow()) and functionProtoType(isNoThrow())
      match the declarations of g, and h, but not f, i or j.
Matcher<FunctionDecl> | isStaticStorageClass |
    Matches variable/function declarations that have "static" storage
    class specifier ("static" keyword) written in the source.

    Given:
      static void f() {}
      static int i = 0;
      extern int j;
      int k;
    functionDecl(isStaticStorageClass())
      matches the function declaration f.
    varDecl(isStaticStorageClass())
      matches the variable declaration i.
Matcher<FunctionDecl> | isTemplateInstantiation |
    Matches template instantiations of function, class, or static
    member variable template instantiations.

    Given
      template <typename T> class X {}; class A {}; X<A> x;
    or
      template <typename T> class X {}; class A {}; template class X<A>;
    or
      template <typename T> class X {}; class A {}; extern template class X<A>;
    cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
      matches the template instantiation of X<A>.

    But given
      template <typename T>  class X {}; class A {};
      template <> class X<A> {}; X<A> x;
    cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
      does not match, as X<A> is an explicit template specialization.

    Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>
Matcher<FunctionDecl> | isVariadic |
    Matches if a function declaration is variadic.

    Example matches f, but not g or h. The function i will not match, even when
    compiled in C mode.
      void f(...);
      void g(int);
      template <typename... Ts> void h(Ts...);
      void i();
Matcher<FunctionDecl> | isWeak |
    Matches weak function declarations.

    Given:
      void foo() __attribute__((__weakref__("__foo")));
      void bar();
    functionDecl(isWeak())
      matches the weak declaration "foo", but not "bar".
Matcher<FunctionDecl> | parameterCountIs | unsigned N
    Matches FunctionDecls and FunctionProtoTypes that have a
    specific parameter count.

    Given
      void f(int i) {}
      void g(int i, int j) {}
      void h(int i, int j);
      void j(int i);
      void k(int x, int y, int z, ...);
    functionDecl(parameterCountIs(2))
      matches g and h
    functionProtoType(parameterCountIs(2))
      matches g and h
    functionProtoType(parameterCountIs(3))
      matches k
Matcher<FunctionProtoType> | hasDynamicExceptionSpec |
    Matches functions that have a dynamic exception specification.

    Given:
      void f();
      void g() noexcept;
      void h() noexcept(true);
      void i() noexcept(false);
      void j() throw();
      void k() throw(int);
      void l() throw(...);
    functionDecl(hasDynamicExceptionSpec()) and
      functionProtoType(hasDynamicExceptionSpec())
      match the declarations of j, k, and l, but not f, g, h, or i.
Matcher<FunctionProtoType> | isNoThrow |
    Matches functions that have a non-throwing exception specification.

    Given:
      void f();
      void g() noexcept;
      void h() throw();
      void i() throw(int);
      void j() noexcept(false);
    functionDecl(isNoThrow()) and functionProtoType(isNoThrow())
      match the declarations of g, and h, but not f, i or j.
Matcher<FunctionProtoType> | parameterCountIs | unsigned N
    Matches FunctionDecls and FunctionProtoTypes that have a
    specific parameter count.

    Given
      void f(int i) {}
      void g(int i, int j) {}
      void h(int i, int j);
      void j(int i);
      void k(int x, int y, int z, ...);
    functionDecl(parameterCountIs(2))
      matches g and h
    functionProtoType(parameterCountIs(2))
      matches g and h
    functionProtoType(parameterCountIs(3))
      matches k
Matcher<IfStmt> | isConstexpr |
    Matches constexpr variable and function declarations,
           and if constexpr.

    Given:
      constexpr int foo = 42;
      constexpr int bar();
      void baz() { if constexpr(1 > 0) {} }
    varDecl(isConstexpr())
      matches the declaration of foo.
    functionDecl(isConstexpr())
      matches the declaration of bar.
    ifStmt(isConstexpr())
      matches the if statement in baz.
Matcher<IntegerLiteral> | equals | bool Value
Matcher<IntegerLiteral> | equals | const ValueT Value
    Matches literals that are equal to the given value of type ValueT.

    Given
      f('false, 3.14, 42);
    characterLiteral(equals(0))
      matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
      match false
    floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
      match 3.14
    integerLiteral(equals(42))
      matches 42

    Note that you cannot directly match a negative numeric literal because the
    minus sign is not part of the literal: It is a unary operator whose operand
    is the positive numeric literal. Instead, you must use a unaryOperator()
    matcher to match the minus sign:

    unaryOperator(hasOperatorName("-"),
                  hasUnaryOperand(integerLiteral(equals(13))))

    Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
               Matcher<FloatingLiteral>, Matcher<IntegerLiteral>
Matcher<IntegerLiteral> | equals | double Value
Matcher<IntegerLiteral> | equals | unsigned Value
Matcher<MemberExpr> | isArrow |
    Matches member expressions that are called with '->' as opposed
    to '.'.

    Member calls on the implicit this pointer match as called with '->'.

    Given
      class Y {
        void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
        template <class T> void f() { this->f<T>(); f<T>(); }
        int a;
        static int b;
      };
      template <class T>
      class Z {
        void x() { this->m; }
      };
    memberExpr(isArrow())
      matches this->x, x, y.x, a, this->b
    cxxDependentScopeMemberExpr(isArrow())
      matches this->m
    unresolvedMemberExpr(isArrow())
      matches this->f<T>, f<T>
Matcher<NamedDecl> | hasAnyName | StringRef, ..., StringRef
    Matches NamedDecl nodes that have any of the specified names.

    This matcher is only provided as a performance optimization of hasName.
        hasAnyName(a, b, c)
     is equivalent to, but faster than
        anyOf(hasName(a), hasName(b), hasName(c))
Matcher<NamedDecl> | hasExternalFormalLinkage |
    Matches a declaration that has external formal linkage.

    Example matches only z (matcher = varDecl(hasExternalFormalLinkage()))
    void f() {
      int x;
      static int y;
    }
    int z;

    Example matches f() because it has external formal linkage despite being
    unique to the translation unit as though it has internal likage
    (matcher = functionDecl(hasExternalFormalLinkage()))

    namespace {
    void f() {}
    }
Matcher<NamedDecl> | hasName | StringRef Name
    Matches NamedDecl nodes that have the specified name.

    Supports specifying enclosing namespaces or classes by prefixing the name
    with '<enclosing>::'.
    Does not match typedefs of an underlying type with the given name.

    Example matches X (Name == "X")
      class X;

    Example matches X (Name is one of "::a::b::X", "a::b::X", "b::X", "X")
      namespace a { namespace b { class X; } }
Matcher<NamedDecl> | matchesName | StringRef RegExp, Regex::RegexFlags Flags = NoFlags
    Matches NamedDecl nodes whose fully qualified names contain
    a substring matched by the given RegExp.

    Supports specifying enclosing namespaces or classes by
    prefixing the name with '<enclosing>::'.  Does not match typedefs
    of an underlying type with the given name.

    Example matches X (regexp == "::X")
      class X;

    Example matches X (regexp is one of "::X", "^foo::.*X", among others)
      namespace foo { namespace bar { class X; } }

    If the matcher is used in clang-query, RegexFlags parameter
    should be passed as a quoted string. e.g: "NoFlags".
    Flags can be combined with '|' example "IgnoreCase | BasicRegex"
Matcher<NamespaceDecl> | isAnonymous |
    Matches anonymous namespace declarations.

    Given
      namespace n {
      namespace {} // #1
      }
    namespaceDecl(isAnonymous()) will match #1 but not ::n.
Matcher<NamespaceDecl> | isInline |
    Matches function and namespace declarations that are marked with
    the inline keyword.

    Given
      inline void f();
      void g();
      namespace n {
      inline namespace m {}
      }
    functionDecl(isInline()) will match ::f().
    namespaceDecl(isInline()) will match n::m.
Matcher<OMPDefaultClause> | isFirstPrivateKind |
    Matches if the OpenMP ``default`` clause has ``firstprivate`` kind
    specified.

    Given

      #pragma omp parallel
      #pragma omp parallel default(none)
      #pragma omp parallel default(shared)
      #pragma omp parallel default(firstprivate)

    ``ompDefaultClause(isFirstPrivateKind())`` matches only
    ``default(firstprivate)``.
Matcher<OMPDefaultClause> | isNoneKind |
    Matches if the OpenMP ``default`` clause has ``none`` kind specified.

    Given

      #pragma omp parallel
      #pragma omp parallel default(none)
      #pragma omp parallel default(shared)
      #pragma omp parallel default(firstprivate)

    ``ompDefaultClause(isNoneKind())`` matches only ``default(none)``.
Matcher<OMPDefaultClause> | isSharedKind |
    Matches if the OpenMP ``default`` clause has ``shared`` kind specified.

    Given

      #pragma omp parallel
      #pragma omp parallel default(none)
      #pragma omp parallel default(shared)
      #pragma omp parallel default(firstprivate)

    ``ompDefaultClause(isSharedKind())`` matches only ``default(shared)``.
Matcher<OMPExecutableDirective> | isAllowedToContainClauseKind | OpenMPClauseKind CKind
    Matches if the OpenMP directive is allowed to contain the specified OpenMP
    clause kind.

    Given

      #pragma omp parallel
      #pragma omp parallel for
      #pragma omp          for

    `ompExecutableDirective(isAllowedToContainClause(OMPC_default))`` matches
    ``omp parallel`` and ``omp parallel for``.

    If the matcher is use from clang-query, ``OpenMPClauseKind`` parameter
    should be passed as a quoted string. e.g.,
    ``isAllowedToContainClauseKind("OMPC_default").``
Matcher<OMPExecutableDirective> | isStandaloneDirective |
    Matches standalone OpenMP directives,
    i.e., directives that can't have a structured block.

    Given

      #pragma omp parallel
      {}
      #pragma omp taskyield

    ``ompExecutableDirective(isStandaloneDirective()))`` matches
    ``omp taskyield``.
Matcher<ObjCInterfaceDecl> | isDerivedFrom | std::string BaseName
    Overloaded method as shortcut for isDerivedFrom(hasName(...)).
Matcher<ObjCInterfaceDecl> | isDirectlyDerivedFrom | std::string BaseName
    Overloaded method as shortcut for isDirectlyDerivedFrom(hasName(...)).
Matcher<ObjCInterfaceDecl> | isSameOrDerivedFrom | std::string BaseName
    Overloaded method as shortcut for
    isSameOrDerivedFrom(hasName(...)).
Matcher<ObjCMessageExpr> | argumentCountIs | unsigned N
    Checks that a call expression or a constructor call expression has
    a specific number of arguments (including absent default arguments).

    Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
      void f(int x, int y);
      f(0, 0);
Matcher<ObjCMessageExpr> | hasAnySelector | StringRef, ..., StringRef
    Matches when at least one of the supplied string equals to the
    Selector.getAsString()

     matcher = objCMessageExpr(hasSelector("methodA:", "methodB:"));
     matches both of the expressions below:
        [myObj methodA:argA];
        [myObj methodB:argB];
Matcher<ObjCMessageExpr> | hasKeywordSelector |
    Matches when the selector is a keyword selector

    objCMessageExpr(hasKeywordSelector()) matches the generated setFrame
    message expression in

      UIWebView *webView = ...;
      CGRect bodyFrame = webView.frame;
      bodyFrame.size.height = self.bodyContentHeight;
      webView.frame = bodyFrame;
      //     ^---- matches here
Matcher<ObjCMessageExpr> | hasNullSelector |
    Matches when the selector is the empty selector

    Matches only when the selector of the objCMessageExpr is NULL. This may
    represent an error condition in the tree!
Matcher<ObjCMessageExpr> | hasSelector | std::string BaseName
    Matches when BaseName == Selector.getAsString()

     matcher = objCMessageExpr(hasSelector("loadHTMLString:baseURL:"));
     matches the outer message expr in the code below, but NOT the message
     invocation for self.bodyView.
        [self.bodyView loadHTMLString:html baseURL:NULL];
Matcher<ObjCMessageExpr> | hasUnarySelector |
    Matches when the selector is a Unary Selector

     matcher = objCMessageExpr(matchesSelector(hasUnarySelector());
     matches self.bodyView in the code below, but NOT the outer message
     invocation of "loadHTMLString:baseURL:".
        [self.bodyView loadHTMLString:html baseURL:NULL];
Matcher<ObjCMessageExpr> | isClassMessage |
    Returns true when the Objective-C message is sent to a class.

    Example
    matcher = objcMessageExpr(isClassMessage())
    matches
      [NSString stringWithFormat:@"format"];
    but not
      NSString *x = @"hello";
      [x containsString:@"h"];
Matcher<ObjCMessageExpr> | isInstanceMessage |
    Returns true when the Objective-C message is sent to an instance.

    Example
    matcher = objcMessageExpr(isInstanceMessage())
    matches
      NSString *x = @"hello";
      [x containsString:@"h"];
    but not
      [NSString stringWithFormat:@"format"];
Matcher<ObjCMessageExpr> | matchesSelector | StringRef RegExp, Regex::RegexFlags Flags = NoFlags
    Matches ObjC selectors whose name contains
    a substring matched by the given RegExp.
     matcher = objCMessageExpr(matchesSelector("loadHTMLStringmatches the outer message expr in the code below, but NOT the message
     invocation for self.bodyView.
        [self.bodyView loadHTMLString:html baseURL:NULL];

    If the matcher is used in clang-query, RegexFlags parameter
    should be passed as a quoted string. e.g: "NoFlags".
    Flags can be combined with '|' example "IgnoreCase | BasicRegex"
Matcher<ObjCMessageExpr> | numSelectorArgs | unsigned N
    Matches when the selector has the specified number of arguments

     matcher = objCMessageExpr(numSelectorArgs(0));
     matches self.bodyView in the code below

     matcher = objCMessageExpr(numSelectorArgs(2));
     matches the invocation of "loadHTMLString:baseURL:" but not that
     of self.bodyView
        [self.bodyView loadHTMLString:html baseURL:NULL];
Matcher<ObjCMethodDecl> | isClassMethod |
    Returns true when the Objective-C method declaration is a class method.

    Example
    matcher = objcMethodDecl(isClassMethod())
    matches
    @interface I + (void)foo; @end
    but not
    @interface I - (void)bar; @end
Matcher<ObjCMethodDecl> | isDefinition |
    Matches if a declaration has a body attached.

    Example matches A, va, fa
      class A {};
      class B;  // Doesn't match, as it has no body.
      int va;
      extern int vb;  // Doesn't match, as it doesn't define the variable.
      void fa() {}
      void fb();  // Doesn't match, as it has no body.
      @interface X
      - (void)ma; // Doesn't match, interface is declaration.
      @end
      @implementation X
      - (void)ma {}
      @end

    Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
      Matcher<ObjCMethodDecl>
Matcher<ObjCMethodDecl> | isInstanceMethod |
    Returns true when the Objective-C method declaration is an instance method.

    Example
    matcher = objcMethodDecl(isInstanceMethod())
    matches
    @interface I - (void)bar; @end
    but not
    @interface I + (void)foo; @end
Matcher<ParmVarDecl> | hasDefaultArgument |
    Matches a declaration that has default arguments.

    Example matches y (matcher = parmVarDecl(hasDefaultArgument()))
    void x(int val) {}
    void y(int val = 0) {}

    Deprecated. Use hasInitializer() instead to be able to
    match on the contents of the default argument.  For example:

    void x(int val = 7) {}
    void y(int val = 42) {}
    parmVarDecl(hasInitializer(integerLiteral(equals(42))))
      matches the parameter of y

    A matcher such as
      parmVarDecl(hasInitializer(anything()))
    is equivalent to parmVarDecl(hasDefaultArgument()).
Matcher<ParmVarDecl> | isAtPosition | unsigned N
    Matches the ParmVarDecl nodes that are at the N'th position in the parameter
    list. The parameter list could be that of either a block, function, or
    objc-method.

    Given

    void f(int a, int b, int c) {
    }

    ``parmVarDecl(isAtPosition(0))`` matches ``int a``.

    ``parmVarDecl(isAtPosition(1))`` matches ``int b``.
Matcher<QualType> | asString | std::string Name
    Matches if the matched type is represented by the given string.

    Given
      class Y { public: void x(); };
      void z() { Y* y; y->x(); }
    cxxMemberCallExpr(on(hasType(asString("class Y *"))))
      matches y->x()
Matcher<QualType> | equalsBoundNode | std::string ID
    Matches if a node equals a previously bound node.

    Matches a node if it equals the node previously bound to ID.

    Given
      class X { int a; int b; };
    cxxRecordDecl(
        has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
        has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
      matches the class X, as a and b have the same type.

    Note that when multiple matches are involved via forEach* matchers,
    equalsBoundNodes acts as a filter.
    For example:
    compoundStmt(
        forEachDescendant(varDecl().bind("d")),
        forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
    will trigger a match for each combination of variable declaration
    and reference to that variable declaration within a compound statement.
Matcher<QualType> | hasLocalQualifiers |
    Matches QualType nodes that have local CV-qualifiers attached to
    the node, not hidden within a typedef.

    Given
      typedef const int const_int;
      const_int i;
      int *const j;
      int *volatile k;
      int m;
    varDecl(hasType(hasLocalQualifiers())) matches only j and k.
    i is const-qualified but the qualifier is not local.
Matcher<QualType> | isAnyCharacter |
    Matches QualType nodes that are of character type.

    Given
      void a(char);
      void b(wchar_t);
      void c(double);
    functionDecl(hasAnyParameter(hasType(isAnyCharacter())))
    matches "a(char)", "b(wchar_t)", but not "c(double)".
Matcher<QualType> | isAnyPointer |
    Matches QualType nodes that are of any pointer type; this includes
    the Objective-C object pointer type, which is different despite being
    syntactically similar.

    Given
      int *i = nullptr;

      @interface Foo
      @end
      Foo *f;

      int j;
    varDecl(hasType(isAnyPointer()))
      matches "int *i" and "Foo *f", but not "int j".
Matcher<QualType> | isConstQualified |
    Matches QualType nodes that are const-qualified, i.e., that
    include "top-level" const.

    Given
      void a(int);
      void b(int const);
      void c(const int);
      void d(const int*);
      void e(int const) {};
    functionDecl(hasAnyParameter(hasType(isConstQualified())))
      matches "void b(int const)", "void c(const int)" and
      "void e(int const) {}". It does not match d as there
      is no top-level const on the parameter type "const int *".
Matcher<QualType> | isInteger |
    Matches QualType nodes that are of integer type.

    Given
      void a(int);
      void b(long);
      void c(double);
    functionDecl(hasAnyParameter(hasType(isInteger())))
    matches "a(int)", "b(long)", but not "c(double)".
Matcher<QualType> | isSignedInteger |
    Matches QualType nodes that are of signed integer type.

    Given
      void a(int);
      void b(unsigned long);
      void c(double);
    functionDecl(hasAnyParameter(hasType(isSignedInteger())))
    matches "a(int)", but not "b(unsigned long)" and "c(double)".
Matcher<QualType> | isUnsignedInteger |
    Matches QualType nodes that are of unsigned integer type.

    Given
      void a(int);
      void b(unsigned long);
      void c(double);
    functionDecl(hasAnyParameter(hasType(isUnsignedInteger())))
    matches "b(unsigned long)", but not "a(int)" and "c(double)".
Matcher<QualType> | isVolatileQualified |
    Matches QualType nodes that are volatile-qualified, i.e., that
    include "top-level" volatile.

    Given
      void a(int);
      void b(int volatile);
      void c(volatile int);
      void d(volatile int*);
      void e(int volatile) {};
    functionDecl(hasAnyParameter(hasType(isVolatileQualified())))
      matches "void b(int volatile)", "void c(volatile int)" and
      "void e(int volatile) {}". It does not match d as there
      is no top-level volatile on the parameter type "volatile int *".
Matcher<Stmt> | equalsBoundNode | std::string ID
    Matches if a node equals a previously bound node.

    Matches a node if it equals the node previously bound to ID.

    Given
      class X { int a; int b; };
    cxxRecordDecl(
        has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
        has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
      matches the class X, as a and b have the same type.

    Note that when multiple matches are involved via forEach* matchers,
    equalsBoundNodes acts as a filter.
    For example:
    compoundStmt(
        forEachDescendant(varDecl().bind("d")),
        forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
    will trigger a match for each combination of variable declaration
    and reference to that variable declaration within a compound statement.
Matcher<Stmt> | equalsNode | const Stmt* Other
    Matches if a node equals another node.

    Stmt has pointer identity in the AST.
Matcher<Stmt> | isExpandedFromMacro | std::string MacroName
    Matches statements that are (transitively) expanded from the named macro.
    Does not match if only part of the statement is expanded from that macro or
    if different parts of the the statement are expanded from different
    appearances of the macro.
Matcher<Stmt> | isExpansionInFileMatching | StringRef RegExp, Regex::RegexFlags Flags = NoFlags
    Matches AST nodes that were expanded within files whose name is
    partially matching a given regex.

    Example matches Y but not X
        (matcher = cxxRecordDecl(isExpansionInFileMatching("AST.*"))
      #include "ASTMatcher.h"
      class X {};
    ASTMatcher.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

    If the matcher is used in clang-query, RegexFlags parameter
    should be passed as a quoted string. e.g: "NoFlags".
    Flags can be combined with '|' example "IgnoreCase | BasicRegex"
Matcher<Stmt> | isExpansionInMainFile |
    Matches AST nodes that were expanded within the main-file.

    Example matches X but not Y
      (matcher = cxxRecordDecl(isExpansionInMainFile())
      #include <Y.h>
      class X {};
    Y.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>
Matcher<Stmt> | isExpansionInSystemHeader |
    Matches AST nodes that were expanded within system-header-files.

    Example matches Y but not X
        (matcher = cxxRecordDecl(isExpansionInSystemHeader())
      #include <SystemHeader.h>
      class X {};
    SystemHeader.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>
Matcher<Stmt> | isInTemplateInstantiation |
    Matches statements inside of a template instantiation.

    Given
      int j;
      template<typename T> void A(T t) { T i; j += 42;}
      A(0);
      A(0U);
    declStmt(isInTemplateInstantiation())
      matches 'int i;' and 'unsigned i'.
    unless(stmt(isInTemplateInstantiation()))
      will NOT match j += 42; as it's shared between the template definition and
      instantiation.
Matcher<StringLiteral> | hasSize | unsigned N
    Matches nodes that have the specified size.

    Given
      int a[42];
      int b[2 * 21];
      int c[41], d[43];
      char *s = "abcd";
      wchar_t *ws = L"abcd";
      char *w = "a";
    constantArrayType(hasSize(42))
      matches "int a[42]" and "int b[2 * 21]"
    stringLiteral(hasSize(4))
      matches "abcd", L"abcd"
Matcher<TagDecl> | isClass |
    Matches TagDecl object that are spelled with "class."

    Example matches C, but not S, U or E.
      struct S {};
      class C {};
      union U {};
      enum E {};
Matcher<TagDecl> | isDefinition |
    Matches if a declaration has a body attached.

    Example matches A, va, fa
      class A {};
      class B;  // Doesn't match, as it has no body.
      int va;
      extern int vb;  // Doesn't match, as it doesn't define the variable.
      void fa() {}
      void fb();  // Doesn't match, as it has no body.
      @interface X
      - (void)ma; // Doesn't match, interface is declaration.
      @end
      @implementation X
      - (void)ma {}
      @end

    Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
      Matcher<ObjCMethodDecl>
Matcher<TagDecl> | isEnum |
    Matches TagDecl object that are spelled with "enum."

    Example matches E, but not C, S or U.
      struct S {};
      class C {};
      union U {};
      enum E {};
Matcher<TagDecl> | isStruct |
    Matches TagDecl object that are spelled with "struct."

    Example matches S, but not C, U or E.
      struct S {};
      class C {};
      union U {};
      enum E {};
Matcher<TagDecl> | isUnion |
    Matches TagDecl object that are spelled with "union."

    Example matches U, but not C, S or E.
      struct S {};
      class C {};
      union U {};
      enum E {};
Matcher<TemplateArgument> | equalsIntegralValue | std::string Value
    Matches a TemplateArgument of integral type with a given value.

    Note that 'Value' is a string as the template argument's value is
    an arbitrary precision integer. 'Value' must be euqal to the canonical
    representation of that integral value in base 10.

    Given
      template<int T> struct C {};
      C<42> c;
    classTemplateSpecializationDecl(
      hasAnyTemplateArgument(equalsIntegralValue("42")))
      matches the implicit instantiation of C in C<42>.
Matcher<TemplateArgument> | isIntegral |
    Matches a TemplateArgument that is an integral value.

    Given
      template<int T> struct C {};
      C<42> c;
    classTemplateSpecializationDecl(
      hasAnyTemplateArgument(isIntegral()))
      matches the implicit instantiation of C in C<42>
      with isIntegral() matching 42.
Matcher<TemplateSpecializationType> | templateArgumentCountIs | unsigned N
    Matches if the number of template arguments equals N.

    Given
      template<typename T> struct C {};
      C<int> c;
    classTemplateSpecializationDecl(templateArgumentCountIs(1))
      matches C<int>.
Matcher<TypeLoc> | isExpandedFromMacro | std::string MacroName
    Matches statements that are (transitively) expanded from the named macro.
    Does not match if only part of the statement is expanded from that macro or
    if different parts of the the statement are expanded from different
    appearances of the macro.
Matcher<TypeLoc> | isExpansionInFileMatching | StringRef RegExp, Regex::RegexFlags Flags = NoFlags
    Matches AST nodes that were expanded within files whose name is
    partially matching a given regex.

    Example matches Y but not X
        (matcher = cxxRecordDecl(isExpansionInFileMatching("AST.*"))
      #include "ASTMatcher.h"
      class X {};
    ASTMatcher.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

    If the matcher is used in clang-query, RegexFlags parameter
    should be passed as a quoted string. e.g: "NoFlags".
    Flags can be combined with '|' example "IgnoreCase | BasicRegex"
Matcher<TypeLoc> | isExpansionInMainFile |
    Matches AST nodes that were expanded within the main-file.

    Example matches X but not Y
      (matcher = cxxRecordDecl(isExpansionInMainFile())
      #include <Y.h>
      class X {};
    Y.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>
Matcher<TypeLoc> | isExpansionInSystemHeader |
    Matches AST nodes that were expanded within system-header-files.

    Example matches Y but not X
        (matcher = cxxRecordDecl(isExpansionInSystemHeader())
      #include <SystemHeader.h>
      class X {};
    SystemHeader.h:
      class Y {};

    Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>
Matcher<Type> | booleanType |
    Matches type bool.

    Given
     struct S { bool func(); };
    functionDecl(returns(booleanType()))
      matches "bool func();"
Matcher<Type> | equalsBoundNode | std::string ID
    Matches if a node equals a previously bound node.

    Matches a node if it equals the node previously bound to ID.

    Given
      class X { int a; int b; };
    cxxRecordDecl(
        has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
        has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
      matches the class X, as a and b have the same type.

    Note that when multiple matches are involved via forEach* matchers,
    equalsBoundNodes acts as a filter.
    For example:
    compoundStmt(
        forEachDescendant(varDecl().bind("d")),
        forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
    will trigger a match for each combination of variable declaration
    and reference to that variable declaration within a compound statement.
Matcher<Type> | equalsNode | const Type* Other
    Matches if a node equals another node.

    Type has pointer identity in the AST.
Matcher<Type> | realFloatingPointType |
    Matches any real floating-point type (float, double, long double).

    Given
      int i;
      float f;
    realFloatingPointType()
      matches "float f" but not "int i"
Matcher<Type> | voidType |
    Matches type void.

    Given
     struct S { void func(); };
    functionDecl(returns(voidType()))
      matches "void func();"
Matcher<UnaryExprOrTypeTraitExpr> | ofKind | UnaryExprOrTypeTrait Kind
    Matches unary expressions of a certain kind.

    Given
      int x;
      int s = sizeof(x) + alignof(x)
    unaryExprOrTypeTraitExpr(ofKind(UETT_SizeOf))
      matches sizeof(x)

    If the matcher is use from clang-query, UnaryExprOrTypeTrait parameter
    should be passed as a quoted string. e.g., ofKind("UETT_SizeOf").
Matcher<UnaryOperator> | hasAnyOperatorName | StringRef, ..., StringRef
    Matches operator expressions (binary or unary) that have any of the
    specified names.

       hasAnyOperatorName("+", "-")
     Is equivalent to
       anyOf(hasOperatorName("+"), hasOperatorName("-"))
Matcher<UnaryOperator> | hasOperatorName | std::string Name
    Matches the operator Name of operator expressions (binary or
    unary).

    Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
      !(a || b)
Matcher<UnresolvedMemberExpr> | isArrow |
    Matches member expressions that are called with '->' as opposed
    to '.'.

    Member calls on the implicit this pointer match as called with '->'.

    Given
      class Y {
        void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
        template <class T> void f() { this->f<T>(); f<T>(); }
        int a;
        static int b;
      };
      template <class T>
      class Z {
        void x() { this->m; }
      };
    memberExpr(isArrow())
      matches this->x, x, y.x, a, this->b
    cxxDependentScopeMemberExpr(isArrow())
      matches this->m
    unresolvedMemberExpr(isArrow())
      matches this->f<T>, f<T>
Matcher<VarDecl> | hasAutomaticStorageDuration |
    Matches a variable declaration that has automatic storage duration.

    Example matches x, but not y, z, or a.
    (matcher = varDecl(hasAutomaticStorageDuration())
    void f() {
      int x;
      static int y;
      thread_local int z;
    }
    int a;
Matcher<VarDecl> | hasGlobalStorage |
    Matches a variable declaration that does not have local storage.

    Example matches y and z (matcher = varDecl(hasGlobalStorage())
    void f() {
      int x;
      static int y;
    }
    int z;
Matcher<VarDecl> | hasLocalStorage |
    Matches a variable declaration that has function scope and is a
    non-static local variable.

    Example matches x (matcher = varDecl(hasLocalStorage())
    void f() {
      int x;
      static int y;
    }
    int z;
Matcher<VarDecl> | hasStaticStorageDuration |
    Matches a variable declaration that has static storage duration.
    It includes the variable declared at namespace scope and those declared
    with "static" and "extern" storage class specifiers.

    void f() {
      int x;
      static int y;
      thread_local int z;
    }
    int a;
    static int b;
    extern int c;
    varDecl(hasStaticStorageDuration())
      matches the function declaration y, a, b and c.
Matcher<VarDecl> | hasThreadStorageDuration |
    Matches a variable declaration that has thread storage duration.

    Example matches z, but not x, z, or a.
    (matcher = varDecl(hasThreadStorageDuration())
    void f() {
      int x;
      static int y;
      thread_local int z;
    }
    int a;
Matcher<VarDecl> | isConstexpr |
    Matches constexpr variable and function declarations,
           and if constexpr.

    Given:
      constexpr int foo = 42;
      constexpr int bar();
      void baz() { if constexpr(1 > 0) {} }
    varDecl(isConstexpr())
      matches the declaration of foo.
    functionDecl(isConstexpr())
      matches the declaration of bar.
    ifStmt(isConstexpr())
      matches the if statement in baz.
Matcher<VarDecl> | isDefinition |
    Matches if a declaration has a body attached.

    Example matches A, va, fa
      class A {};
      class B;  // Doesn't match, as it has no body.
      int va;
      extern int vb;  // Doesn't match, as it doesn't define the variable.
      void fa() {}
      void fb();  // Doesn't match, as it has no body.
      @interface X
      - (void)ma; // Doesn't match, interface is declaration.
      @end
      @implementation X
      - (void)ma {}
      @end

    Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
      Matcher<ObjCMethodDecl>
Matcher<VarDecl> | isExceptionVariable |
    Matches a variable declaration that is an exception variable from
    a C++ catch block, or an Objective-C statement.

    Example matches x (matcher = varDecl(isExceptionVariable())
    void f(int y) {
      try {
      } catch (int x) {
      }
    }
Matcher<VarDecl> | isExplicitTemplateSpecialization |
    Matches explicit template specializations of function, class, or
    static member variable template instantiations.

    Given
      template<typename T> void A(T t) { }
      template<> void A(int N) { }
    functionDecl(isExplicitTemplateSpecialization())
      matches the specialization A<int>().

    Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>
Matcher<VarDecl> | isExternC |
    Matches extern "C" function or variable declarations.

    Given:
      extern "C" void f() {}
      extern "C" { void g() {} }
      void h() {}
      extern "C" int x = 1;
      extern "C" int y = 2;
      int z = 3;
    functionDecl(isExternC())
      matches the declaration of f and g, but not the declaration of h.
    varDecl(isExternC())
      matches the declaration of x and y, but not the declaration of z.
Matcher<VarDecl> | isStaticLocal |
    Matches a static variable with local scope.

    Example matches y (matcher = varDecl(isStaticLocal()))
    void f() {
      int x;
      static int y;
    }
    static int z;
Matcher<VarDecl> | isStaticStorageClass |
    Matches variable/function declarations that have "static" storage
    class specifier ("static" keyword) written in the source.

    Given:
      static void f() {}
      static int i = 0;
      extern int j;
      int k;
    functionDecl(isStaticStorageClass())
      matches the function declaration f.
    varDecl(isStaticStorageClass())
      matches the variable declaration i.
Matcher<VarDecl> | isTemplateInstantiation |
    Matches template instantiations of function, class, or static
    member variable template instantiations.

    Given
      template <typename T> class X {}; class A {}; X<A> x;
    or
      template <typename T> class X {}; class A {}; template class X<A>;
    or
      template <typename T> class X {}; class A {}; extern template class X<A>;
    cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
      matches the template instantiation of X<A>.

    But given
      template <typename T>  class X {}; class A {};
      template <> class X<A> {}; X<A> x;
    cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
      does not match, as X<A> is an explicit template specialization.

    Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

## AST Traversal Matchers

Traversal matchers specify the relationship to other nodes that are reachable from the current node.

Note that there are special traversal matchers (has, hasDescendant, forEach and forEachDescendant) which work on all nodes and allow users to write more generic match expressions.

Return type | Name | Parameters
--- | --- | ---
Matcher<*> | binaryOperation | Matcher<*>...Matcher<*>
    Matches nodes which can be used with binary operators.

    The code
      var1 != var2;
    might be represented in the clang AST as a binaryOperator, a
    cxxOperatorCallExpr or a cxxRewrittenBinaryOperator, depending on

    * whether the types of var1 and var2 are fundamental (binaryOperator) or at
      least one is a class type (cxxOperatorCallExpr)
    * whether the code appears in a template declaration, if at least one of the
      vars is a dependent-type (binaryOperator)
    * whether the code relies on a rewritten binary operator, such as a
    spaceship operator or an inverted equality operator
    (cxxRewrittenBinaryOperator)

    This matcher elides details in places where the matchers for the nodes are
    compatible.

    Given
      binaryOperation(
        hasOperatorName("!="),
        hasLHS(expr().bind("lhs")),
        hasRHS(expr().bind("rhs"))
      )
    matches each use of "!=" in:
      struct S{
          bool operator!=(const S&) const;
      };

      void foo()
      {
         1 != 2;
         S() != S();
      }

      template<typename T>
      void templ()
      {
         1 != 2;
         T() != S();
      }
      struct HasOpEq
      {
          bool operator==(const HasOpEq &) const;
      };

      void inverse()
      {
          HasOpEq s1;
          HasOpEq s2;
          if (s1 != s2)
              return;
      }

      struct HasSpaceship
      {
          bool operator<=>(const HasOpEq &) const;
      };

      void use_spaceship()
      {
          HasSpaceship s1;
          HasSpaceship s2;
          if (s1 != s2)
              return;
      }
Matcher<*> | eachOf | Matcher<*>, ..., Matcher<*>
    Matches if any of the given matchers matches.

    Unlike anyOf, eachOf will generate a match result for each
    matching submatcher.

    For example, in:
      class A { int a; int b; };
    The matcher:
      cxxRecordDecl(eachOf(has(fieldDecl(hasName("a")).bind("v")),
                           has(fieldDecl(hasName("b")).bind("v"))))
    will generate two results binding "v", the first of which binds
    the field declaration of a, the second the field declaration of
    b.

    Usable as: Any Matcher
Matcher<*> | findAll | Matcher<*> Matcher
    Matches if the node or any descendant matches.

    Generates results for each match.

    For example, in:
      class A { class B {}; class C {}; };
    The matcher:
      cxxRecordDecl(hasName("::A"),
                    findAll(cxxRecordDecl(isDefinition()).bind("m")))
    will generate results for A, B and C.

    Usable as: Any Matcher
Matcher<*> | forEachDescendant | Matcher<*>
    Matches AST nodes that have descendant AST nodes that match the
    provided matcher.

    Example matches X, A, A::X, B, B::C, B::C::X
      (matcher = cxxRecordDecl(forEachDescendant(cxxRecordDecl(hasName("X")))))
      class X {};
      class A { class X {}; };  // Matches A, because A::X is a class of name
                                // X inside A.
      class B { class C { class X {}; }; };

    DescendantT must be an AST base type.

    As opposed to 'hasDescendant', 'forEachDescendant' will cause a match for
    each result that matches instead of only on the first one.

    Note: Recursively combined ForEachDescendant can cause many matches:
      cxxRecordDecl(forEachDescendant(cxxRecordDecl(
        forEachDescendant(cxxRecordDecl())
      )))
    will match 10 times (plus injected class name matches) on:
      class A { class B { class C { class D { class E {}; }; }; }; };

    Usable as: Any Matcher
Matcher<*> | forEach | Matcher<*>
    Matches AST nodes that have child AST nodes that match the
    provided matcher.

    Example matches X, Y, Y::X, Z::Y, Z::Y::X
      (matcher = cxxRecordDecl(forEach(cxxRecordDecl(hasName("X")))
      class X {};
      class Y { class X {}; };  // Matches Y, because Y::X is a class of name X
                                // inside Y.
      class Z { class Y { class X {}; }; };  // Does not match Z.

    ChildT must be an AST base type.

    As opposed to 'has', 'forEach' will cause a match for each result that
    matches instead of only on the first one.

    Usable as: Any Matcher
Matcher<*> | hasAncestor | Matcher<*>
    Matches AST nodes that have an ancestor that matches the provided
    matcher.

    Given
    void f() { if (true) { int x = 42; } }
    void g() { for (;;) { int x = 43; } }
    expr(integerLiteral(hasAncestor(ifStmt()))) matches 42, but not 43.

    Usable as: Any Matcher
Matcher<*> | hasDescendant | Matcher<*>
    Matches AST nodes that have descendant AST nodes that match the
    provided matcher.

    Example matches X, Y, Z
        (matcher = cxxRecordDecl(hasDescendant(cxxRecordDecl(hasName("X")))))
      class X {};  // Matches X, because X::X is a class of name X inside X.
      class Y { class X {}; };
      class Z { class Y { class X {}; }; };

    DescendantT must be an AST base type.

    Usable as: Any Matcher
Matcher<*> | has | Matcher<*>
    Matches AST nodes that have child AST nodes that match the
    provided matcher.

    Example matches X, Y
      (matcher = cxxRecordDecl(has(cxxRecordDecl(hasName("X")))
      class X {};  // Matches X, because X::X is a class of name X inside X.
      class Y { class X {}; };
      class Z { class Y { class X {}; }; };  // Does not match Z.

    ChildT must be an AST base type.

    Usable as: Any Matcher
    Note that has is direct matcher, so it also matches things like implicit
    casts and paren casts. If you are matching with expr then you should
    probably consider using ignoringParenImpCasts like:
    has(ignoringParenImpCasts(expr())).
Matcher<*> | hasParent | Matcher<*>
    Matches AST nodes that have a parent that matches the provided
    matcher.

    Given
    void f() { for (;;) { int x = 42; if (true) { int x = 43; } } }
    compoundStmt(hasParent(ifStmt())) matches "{ int x = 43; }".

    Usable as: Any Matcher
Matcher<*> | optionally | Matcher<*>
    Matches any node regardless of the submatcher.

    However, optionally will retain any bindings generated by the submatcher.
    Useful when additional information which may or may not present about a main
    matching node is desired.

    For example, in:
      class Foo {
        int bar;
      }
    The matcher:
      cxxRecordDecl(
        optionally(has(
          fieldDecl(hasName("bar")).bind("var")
      ))).bind("record")
    will produce a result binding for both "record" and "var".
    The matcher will produce a "record" binding for even if there is no data
    member named "bar" in that class.

    Usable as: Any Matcher
Matcher<*> | traverse | TraversalKind TK, Matcher<*> InnerMatcher
    Causes all nested matchers to be matched with the specified traversal kind.

    Given
      void foo()
      {
          int i = 3.0;
      }
    The matcher
      traverse(TK_IgnoreUnlessSpelledInSource,
        varDecl(hasInitializer(floatLiteral().bind("init")))
      )
    matches the variable declaration with "init" bound to the "3.0".
Matcher<AbstractConditionalOperator> | hasCondition | Matcher<Expr> InnerMatcher
    Matches the condition expression of an if statement, for loop,
    switch statement or conditional operator.

    Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
      if (true) {}
Matcher<AbstractConditionalOperator> | hasFalseExpression | Matcher<Expr> InnerMatcher
    Matches the false branch expression of a conditional operator
    (binary or ternary).

    Example matches b
      condition ? a : b
      condition ?: b
Matcher<AbstractConditionalOperator> | hasTrueExpression | Matcher<Expr> InnerMatcher
    Matches the true branch expression of a conditional operator.

    Example 1 (conditional ternary operator): matches a
      condition ? a : b

    Example 2 (conditional binary operator): matches opaqueValueExpr(condition)
      condition ?: b
Matcher<AddrLabelExpr> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<ArraySubscriptExpr> | hasBase | Matcher<Expr> InnerMatcher
    Matches the base expression of an array subscript expression.

    Given
      int i[5];
      void f() { i[1] = 42; }
    arraySubscriptExpression(hasBase(implicitCastExpr(
        hasSourceExpression(declRefExpr()))))
      matches i[1] with the declRefExpr() matching i
Matcher<ArraySubscriptExpr> | hasIndex | Matcher<Expr> InnerMatcher
    Matches the index expression of an array subscript expression.

    Given
      int i[5];
      void f() { i[1] = 42; }
    arraySubscriptExpression(hasIndex(integerLiteral()))
      matches i[1] with the integerLiteral() matching 1
Matcher<ArraySubscriptExpr> | hasLHS | Matcher<Expr> InnerMatcher
    Matches the left hand side of binary operator expressions.

    Example matches a (matcher = binaryOperator(hasLHS()))
      a || b
Matcher<ArraySubscriptExpr> | hasRHS | Matcher<Expr> InnerMatcher
    Matches the right hand side of binary operator expressions.

    Example matches b (matcher = binaryOperator(hasRHS()))
      a || b
Matcher<ArrayType> | hasElementType | Matcher<Type>
    Matches arrays and C99 complex types that have a specific element
    type.

    Given
      struct A {};
      A a[7];
      int b[7];
    arrayType(hasElementType(builtinType()))
      matches "int b[7]"

    Usable as: Matcher<ArrayType>, Matcher<ComplexType>
Matcher<AtomicType> | hasValueType | Matcher<Type>
    Matches atomic types with a specific value type.

    Given
      _Atomic(int) i;
      _Atomic(float) f;
    atomicType(hasValueType(isInteger()))
     matches "_Atomic(int) i"

    Usable as: Matcher<AtomicType>
Matcher<AutoType> | hasDeducedType | Matcher<Type>
    Matches AutoType nodes where the deduced type is a specific type.

    Note: There is no TypeLoc for the deduced type and thus no
    getDeducedLoc() matcher.

    Given
      auto a = 1;
      auto b = 2.0;
    autoType(hasDeducedType(isInteger()))
      matches "auto a"

    Usable as: Matcher<AutoType>
Matcher<BinaryOperator> | hasEitherOperand | Matcher<Expr> InnerMatcher
    Matches if either the left hand side or the right hand side of a
    binary operator matches.
Matcher<BinaryOperator> | hasLHS | Matcher<Expr> InnerMatcher
    Matches the left hand side of binary operator expressions.

    Example matches a (matcher = binaryOperator(hasLHS()))
      a || b
Matcher<BinaryOperator> | hasOperands | Matcher<Expr> Matcher1, Matcher<Expr> Matcher2
    Matches if both matchers match with opposite sides of the binary operator.

    Example matcher = binaryOperator(hasOperands(integerLiteral(equals(1),
                                                 integerLiteral(equals(2)))
      1 + 2 // Match
      2 + 1 // Match
      1 + 1 // No match
      2 + 2 // No match
Matcher<BinaryOperator> | hasRHS | Matcher<Expr> InnerMatcher
    Matches the right hand side of binary operator expressions.

    Example matches b (matcher = binaryOperator(hasRHS()))
      a || b
Matcher<BlockDecl> | hasAnyParameter | Matcher<ParmVarDecl> InnerMatcher
    Matches any parameter of a function or an ObjC method declaration or a
    block.

    Does not match the 'this' parameter of a method.

    Given
      class X { void f(int x, int y, int z) {} };
    cxxMethodDecl(hasAnyParameter(hasName("y")))
      matches f(int x, int y, int z) {}
    with hasAnyParameter(...)
      matching int y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end

    the matcher objcMethodDecl(hasAnyParameter(hasName("y")))
    matches the declaration of method f with hasParameter
    matching y.

    For blocks, given
      b = ^(int y) { printf("%d", y) };

    the matcher blockDecl(hasAnyParameter(hasName("y")))
    matches the declaration of the block b with hasParameter
    matching y.
Matcher<BlockDecl> | hasParameter | unsigned N, Matcher<ParmVarDecl> InnerMatcher
    Matches the n'th parameter of a function or an ObjC method
    declaration or a block.

    Given
      class X { void f(int x) {} };
    cxxMethodDecl(hasParameter(0, hasType(varDecl())))
      matches f(int x) {}
    with hasParameter(...)
      matching int x

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end

    the matcher objcMethodDecl(hasParameter(0, hasName("y")))
    matches the declaration of method f with hasParameter
    matching y.
Matcher<BlockPointerType> | pointee | Matcher<Type>
    Narrows PointerType (and similar) matchers to those where the
    pointee matches a given matcher.

    Given
      int *a;
      int const *b;
      float const *f;
    pointerType(pointee(isConstQualified(), isInteger()))
      matches "int const *b"

    Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
      Matcher<PointerType>, Matcher<ReferenceType>
Matcher<CXXBaseSpecifier> | hasType | Matcher<Decl> InnerMatcher
    Overloaded to match the declaration of the expression's or value
    declaration's type.

    In case of a value declaration (for example a variable declaration),
    this resolves one layer of indirection. For example, in the value
    declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
    X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
    declaration of x.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     class Y { friend class X; };

    Example matches class Derived
    (matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
    class Base {};
    class Derived : Base {};

    Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
    Matcher<CXXBaseSpecifier>
Matcher<CXXConstructExpr> | forEachArgumentWithParam | Matcher<Expr> ArgMatcher, Matcher<ParmVarDecl> ParamMatcher
    Matches all arguments and their respective ParmVarDecl.

    Given
      void f(int i);
      int y;
      f(y);
    callExpr(
      forEachArgumentWithParam(
        declRefExpr(to(varDecl(hasName("y")))),
        parmVarDecl(hasType(isInteger()))
    ))
      matches f(y);
    with declRefExpr(...)
      matching int y
    and parmVarDecl(...)
      matching int i
Matcher<CXXConstructExpr> | forEachArgumentWithParamType | Matcher<Expr> ArgMatcher, Matcher<QualType> ParamMatcher
    Matches all arguments and their respective types for a CallExpr or
    CXXConstructExpr. It is very similar to forEachArgumentWithParam but
    it works on calls through function pointers as well.

    The difference is, that function pointers do not provide access to a
    ParmVarDecl, but only the QualType for each argument.

    Given
      void f(int i);
      int y;
      f(y);
      void (*f_ptr)(int) = f;
      f_ptr(y);
    callExpr(
      forEachArgumentWithParamType(
        declRefExpr(to(varDecl(hasName("y")))),
        qualType(isInteger()).bind("type)
    ))
      matches f(y) and f_ptr(y)
    with declRefExpr(...)
      matching int y
    and qualType(...)
      matching int
Matcher<CXXConstructExpr> | hasAnyArgument | Matcher<Expr> InnerMatcher
    Matches any argument of a call expression or a constructor call
    expression, or an ObjC-message-send expression.

    Given
      void x(int, int, int) { int y; x(1, y, 42); }
    callExpr(hasAnyArgument(declRefExpr()))
      matches x(1, y, 42)
    with hasAnyArgument(...)
      matching y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end
      void foo(I *i) { [i f:12]; }
    objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
      matches [i f:12]
Matcher<CXXConstructExpr> | hasArgument | unsigned N, Matcher<Expr> InnerMatcher
    Matches the n'th argument of a call expression or a constructor
    call expression.

    Example matches y in x(y)
        (matcher = callExpr(hasArgument(0, declRefExpr())))
      void x(int) { int y; x(y); }
Matcher<CXXConstructExpr> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<CXXConstructorDecl> | forEachConstructorInitializer | Matcher<CXXCtorInitializer> InnerMatcher
    Matches each constructor initializer in a constructor definition.

    Given
      class A { A() : i(42), j(42) {} int i; int j; };
    cxxConstructorDecl(forEachConstructorInitializer(
      forField(decl().bind("x"))
    ))
      will trigger two matches, binding for 'i' and 'j' respectively.
Matcher<CXXConstructorDecl> | hasAnyConstructorInitializer | Matcher<CXXCtorInitializer> InnerMatcher
    Matches a constructor initializer.

    Given
      struct Foo {
        Foo() : foo_(1) { }
        int foo_;
      };
    cxxRecordDecl(has(cxxConstructorDecl(
      hasAnyConstructorInitializer(anything())
    )))
      record matches Foo, hasAnyConstructorInitializer matches foo_(1)
Matcher<CXXCtorInitializer> | forField | Matcher<FieldDecl> InnerMatcher
    Matches the field declaration of a constructor initializer.

    Given
      struct Foo {
        Foo() : foo_(1) { }
        int foo_;
      };
    cxxRecordDecl(has(cxxConstructorDecl(hasAnyConstructorInitializer(
        forField(hasName("foo_"))))))
      matches Foo
    with forField matching foo_
Matcher<CXXCtorInitializer> | withInitializer | Matcher<Expr> InnerMatcher
    Matches the initializer expression of a constructor initializer.

    Given
      struct Foo {
        Foo() : foo_(1) { }
        int foo_;
      };
    cxxRecordDecl(has(cxxConstructorDecl(hasAnyConstructorInitializer(
        withInitializer(integerLiteral(equals(1)))))))
      matches Foo
    with withInitializer matching (1)
Matcher<CXXDependentScopeMemberExpr> | hasObjectExpression | Matcher<Expr> InnerMatcher
    Matches a member expression where the object expression is matched by a
    given matcher. Implicit object expressions are included; that is, it matches
    use of implicit `this`.

    Given
      struct X {
        int m;
        int f(X x) { x.m; return m; }
      };
    memberExpr(hasObjectExpression(hasType(cxxRecordDecl(hasName("X")))))
      matches `x.m`, but not `m`; however,
    memberExpr(hasObjectExpression(hasType(pointsTo(
         cxxRecordDecl(hasName("X"))))))
      matches `m` (aka. `this->m`), but not `x.m`.
Matcher<CXXForRangeStmt> | hasBody | Matcher<Stmt> InnerMatcher
Matcher<CXXForRangeStmt> | hasInitStatement | Matcher<Stmt> InnerMatcher
    Matches selection statements with initializer.

    Given:
     void foo() {
       if (int i = foobar(); i > 0) {}
       switch (int i = foobar(); i) {}
       for (auto& a = get_range(); auto& x : a) {}
     }
     void bar() {
       if (foobar() > 0) {}
       switch (foobar()) {}
       for (auto& x : get_range()) {}
     }
    ifStmt(hasInitStatement(anything()))
      matches the if statement in foo but not in bar.
    switchStmt(hasInitStatement(anything()))
      matches the switch statement in foo but not in bar.
    cxxForRangeStmt(hasInitStatement(anything()))
      matches the range for statement in foo but not in bar.
Matcher<CXXForRangeStmt> | hasLoopVariable | Matcher<VarDecl> InnerMatcher
    Matches the initialization statement of a for loop.

    Example:
        forStmt(hasLoopVariable(anything()))
    matches 'int x' in
        for (int x : a) { }
Matcher<CXXForRangeStmt> | hasRangeInit | Matcher<Expr> InnerMatcher
    Matches the range initialization statement of a for loop.

    Example:
        forStmt(hasRangeInit(anything()))
    matches 'a' in
        for (int x : a) { }
Matcher<CXXMemberCallExpr> | onImplicitObjectArgument | Matcher<Expr> InnerMatcher
    Matches on the implicit object argument of a member call expression. Unlike
    `on`, matches the argument directly without stripping away anything.

    Given
      class Y { public: void m(); };
      Y g();
      class X : public Y { void g(); };
      void z(Y y, X x) { y.m(); x.m(); x.g(); (g()).m(); }
    cxxMemberCallExpr(onImplicitObjectArgument(hasType(
        cxxRecordDecl(hasName("Y")))))
      matches `y.m()`, `x.m()` and (g()).m(), but not `x.g()`.
    cxxMemberCallExpr(on(callExpr()))
      does not match `(g()).m()`, because the parens are not ignored.

    FIXME: Overload to allow directly matching types?
Matcher<CXXMemberCallExpr> | on | Matcher<Expr> InnerMatcher
    Matches on the implicit object argument of a member call expression, after
    stripping off any parentheses or implicit casts.

    Given
      class Y { public: void m(); };
      Y g();
      class X : public Y {};
      void z(Y y, X x) { y.m(); (g()).m(); x.m(); }
    cxxMemberCallExpr(on(hasType(cxxRecordDecl(hasName("Y")))))
      matches `y.m()` and `(g()).m()`.
    cxxMemberCallExpr(on(hasType(cxxRecordDecl(hasName("X")))))
      matches `x.m()`.
    cxxMemberCallExpr(on(callExpr()))
      matches `(g()).m()`.

    FIXME: Overload to allow directly matching types?
Matcher<CXXMemberCallExpr> | thisPointerType | Matcher<Decl> InnerMatcher
    Overloaded to match the type's declaration.
Matcher<CXXMemberCallExpr> | thisPointerType | Matcher<QualType> InnerMatcher
    Matches if the type of the expression's implicit object argument either
    matches the InnerMatcher, or is a pointer to a type that matches the
    InnerMatcher.

    Given
      class Y { public: void m(); };
      class X : public Y { void g(); };
      void z() { Y y; y.m(); Y *p; p->m(); X x; x.m(); x.g(); }
    cxxMemberCallExpr(thisPointerType(hasDeclaration(
        cxxRecordDecl(hasName("Y")))))
      matches `y.m()`, `p->m()` and `x.m()`.
    cxxMemberCallExpr(thisPointerType(hasDeclaration(
        cxxRecordDecl(hasName("X")))))
      matches `x.g()`.
Matcher<CXXMethodDecl> | forEachOverridden | Matcher<CXXMethodDecl> InnerMatcher
    Matches each method overridden by the given method. This matcher may
    produce multiple matches.

    Given
      class A { virtual void f(); };
      class B : public A { void f(); };
      class C : public B { void f(); };
    cxxMethodDecl(ofClass(hasName("C")),
                  forEachOverridden(cxxMethodDecl().bind("b"))).bind("d")
      matches once, with "b" binding "A::f" and "d" binding "C::f" (Note
      that B::f is not overridden by C::f).

    The check can produce multiple matches in case of multiple inheritance, e.g.
      class A1 { virtual void f(); };
      class A2 { virtual void f(); };
      class C : public A1, public A2 { void f(); };
    cxxMethodDecl(ofClass(hasName("C")),
                  forEachOverridden(cxxMethodDecl().bind("b"))).bind("d")
      matches twice, once with "b" binding "A1::f" and "d" binding "C::f", and
      once with "b" binding "A2::f" and "d" binding "C::f".
Matcher<CXXMethodDecl> | ofClass | Matcher<CXXRecordDecl> InnerMatcher
    Matches the class declaration that the given method declaration
    belongs to.

    FIXME: Generalize this for other kinds of declarations.
    FIXME: What other kind of declarations would we need to generalize
    this to?

    Example matches A() in the last line
        (matcher = cxxConstructExpr(hasDeclaration(cxxMethodDecl(
            ofClass(hasName("A"))))))
      class A {
       public:
        A();
      };
      A a = A();
Matcher<CXXNewExpr> | hasAnyPlacementArg | Matcher<Expr> InnerMatcher
    Matches any placement new expression arguments.

    Given:
      MyClass *p1 = new (Storage) MyClass();
    cxxNewExpr(hasAnyPlacementArg(anything()))
      matches the expression 'new (Storage, 16) MyClass()'.
Matcher<CXXNewExpr> | hasArraySize | Matcher<Expr> InnerMatcher
    Matches array new expressions with a given array size.

    Given:
      MyClass *p1 = new MyClass[10];
    cxxNewExpr(hasArraySize(integerLiteral(equals(10))))
      matches the expression 'new MyClass[10]'.
Matcher<CXXNewExpr> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<CXXNewExpr> | hasPlacementArg | unsigned Index, Matcher<Expr> InnerMatcher
    Matches placement new expression arguments.

    Given:
      MyClass *p1 = new (Storage, 16) MyClass();
    cxxNewExpr(hasPlacementArg(1, integerLiteral(equals(16))))
      matches the expression 'new (Storage, 16) MyClass()'.
Matcher<CXXOperatorCallExpr> | hasEitherOperand | Matcher<Expr> InnerMatcher
    Matches if either the left hand side or the right hand side of a
    binary operator matches.
Matcher<CXXOperatorCallExpr> | hasLHS | Matcher<Expr> InnerMatcher
    Matches the left hand side of binary operator expressions.

    Example matches a (matcher = binaryOperator(hasLHS()))
      a || b
Matcher<CXXOperatorCallExpr> | hasOperands | Matcher<Expr> Matcher1, Matcher<Expr> Matcher2
    Matches if both matchers match with opposite sides of the binary operator.

    Example matcher = binaryOperator(hasOperands(integerLiteral(equals(1),
                                                 integerLiteral(equals(2)))
      1 + 2 // Match
      2 + 1 // Match
      1 + 1 // No match
      2 + 2 // No match
Matcher<CXXOperatorCallExpr> | hasRHS | Matcher<Expr> InnerMatcher
    Matches the right hand side of binary operator expressions.

    Example matches b (matcher = binaryOperator(hasRHS()))
      a || b
Matcher<CXXOperatorCallExpr> | hasUnaryOperand | Matcher<Expr> InnerMatcher
    Matches if the operand of a unary operator matches.

    Example matches true (matcher = hasUnaryOperand(
                                      cxxBoolLiteral(equals(true))))
      !true
Matcher<CXXRecordDecl> | hasAnyBase | Matcher<CXXBaseSpecifier> BaseSpecMatcher
    Matches C++ classes that have a direct or indirect base matching BaseSpecMatcher.

    Example:
    matcher hasAnyBase(hasType(cxxRecordDecl(hasName("SpecialBase"))))
      class Foo;
      class Bar : Foo {};
      class Baz : Bar {};
      class SpecialBase;
      class Proxy : SpecialBase {};  // matches Proxy
      class IndirectlyDerived : Proxy {};  //matches IndirectlyDerived

    FIXME: Refactor this and isDerivedFrom to reuse implementation.
Matcher<CXXRecordDecl> | hasDirectBase | Matcher<CXXBaseSpecifier> BaseSpecMatcher
    Matches C++ classes that have a direct base matching BaseSpecMatcher.

    Example:
    matcher hasDirectBase(hasType(cxxRecordDecl(hasName("SpecialBase"))))
      class Foo;
      class Bar : Foo {};
      class Baz : Bar {};
      class SpecialBase;
      class Proxy : SpecialBase {};  // matches Proxy
      class IndirectlyDerived : Proxy {};  // doesn't match
Matcher<CXXRecordDecl> | hasMethod | Matcher<CXXMethodDecl> InnerMatcher
    Matches the first method of a class or struct that satisfies InnerMatcher.

    Given:
      class A { void func(); };
      class B { void member(); };

    cxxRecordDecl(hasMethod(hasName("func"))) matches the declaration of
    A but not B.
Matcher<CXXRecordDecl> | isDerivedFrom | Matcher<NamedDecl> Base
    Matches C++ classes that are directly or indirectly derived from a class
    matching Base, or Objective-C classes that directly or indirectly
    subclass a class matching Base.

    Note that a class is not considered to be derived from itself.

    Example matches Y, Z, C (Base == hasName("X"))
      class X;
      class Y : public X {};  // directly derived
      class Z : public Y {};  // indirectly derived
      typedef X A;
      typedef A B;
      class C : public B {};  // derived from a typedef of X

    In the following example, Bar matches isDerivedFrom(hasName("X")):
      class Foo;
      typedef Foo X;
      class Bar : public Foo {};  // derived from a type that X is a typedef of

    In the following example, Bar matches isDerivedFrom(hasName("NSObject"))
      @interface NSObject @end
      @interface Bar : NSObject @end

    Usable as: Matcher<CXXRecordDecl>, Matcher<ObjCInterfaceDecl>
Matcher<CXXRecordDecl> | isDirectlyDerivedFrom | Matcher<NamedDecl> Base
    Matches C++ or Objective-C classes that are directly derived from a class
    matching Base.

    Note that a class is not considered to be derived from itself.

    Example matches Y, C (Base == hasName("X"))
      class X;
      class Y : public X {};  // directly derived
      class Z : public Y {};  // indirectly derived
      typedef X A;
      typedef A B;
      class C : public B {};  // derived from a typedef of X

    In the following example, Bar matches isDerivedFrom(hasName("X")):
      class Foo;
      typedef Foo X;
      class Bar : public Foo {};  // derived from a type that X is a typedef of
Matcher<CXXRecordDecl> | isSameOrDerivedFrom | Matcher<NamedDecl> Base
    Similar to isDerivedFrom(), but also matches classes that directly
    match Base.
Matcher<CXXRewrittenBinaryOperator> | hasEitherOperand | Matcher<Expr> InnerMatcher
    Matches if either the left hand side or the right hand side of a
    binary operator matches.
Matcher<CXXRewrittenBinaryOperator> | hasLHS | Matcher<Expr> InnerMatcher
    Matches the left hand side of binary operator expressions.

    Example matches a (matcher = binaryOperator(hasLHS()))
      a || b
Matcher<CXXRewrittenBinaryOperator> | hasOperands | Matcher<Expr> Matcher1, Matcher<Expr> Matcher2
    Matches if both matchers match with opposite sides of the binary operator.

    Example matcher = binaryOperator(hasOperands(integerLiteral(equals(1),
                                                 integerLiteral(equals(2)))
      1 + 2 // Match
      2 + 1 // Match
      1 + 1 // No match
      2 + 2 // No match
Matcher<CXXRewrittenBinaryOperator> | hasRHS | Matcher<Expr> InnerMatcher
    Matches the right hand side of binary operator expressions.

    Example matches b (matcher = binaryOperator(hasRHS()))
      a || b
Matcher<CXXUnresolvedConstructExpr> | hasAnyArgument | Matcher<Expr> InnerMatcher
    Matches any argument of a call expression or a constructor call
    expression, or an ObjC-message-send expression.

    Given
      void x(int, int, int) { int y; x(1, y, 42); }
    callExpr(hasAnyArgument(declRefExpr()))
      matches x(1, y, 42)
    with hasAnyArgument(...)
      matching y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end
      void foo(I *i) { [i f:12]; }
    objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
      matches [i f:12]
Matcher<CXXUnresolvedConstructExpr> | hasArgument | unsigned N, Matcher<Expr> InnerMatcher
    Matches the n'th argument of a call expression or a constructor
    call expression.

    Example matches y in x(y)
        (matcher = callExpr(hasArgument(0, declRefExpr())))
      void x(int) { int y; x(y); }
Matcher<CallExpr> | callee | Matcher<Decl> InnerMatcher
    Matches if the call expression's callee's declaration matches the
    given matcher.

    Example matches y.x() (matcher = callExpr(callee(
                                       cxxMethodDecl(hasName("x")))))
      class Y { public: void x(); };
      void z() { Y y; y.x(); }
Matcher<CallExpr> | callee | Matcher<Stmt> InnerMatcher
    Matches if the call expression's callee expression matches.

    Given
      class Y { void x() { this->x(); x(); Y y; y.x(); } };
      void f() { f(); }
    callExpr(callee(expr()))
      matches this->x(), x(), y.x(), f()
    with callee(...)
      matching this->x, x, y.x, f respectively

    Note: Callee cannot take the more general internal::Matcher<Expr>
    because this introduces ambiguous overloads with calls to Callee taking a
    internal::Matcher<Decl>, as the matcher hierarchy is purely
    implemented in terms of implicit casts.
Matcher<CallExpr> | forEachArgumentWithParam | Matcher<Expr> ArgMatcher, Matcher<ParmVarDecl> ParamMatcher
    Matches all arguments and their respective ParmVarDecl.

    Given
      void f(int i);
      int y;
      f(y);
    callExpr(
      forEachArgumentWithParam(
        declRefExpr(to(varDecl(hasName("y")))),
        parmVarDecl(hasType(isInteger()))
    ))
      matches f(y);
    with declRefExpr(...)
      matching int y
    and parmVarDecl(...)
      matching int i
Matcher<CallExpr> | forEachArgumentWithParamType | Matcher<Expr> ArgMatcher, Matcher<QualType> ParamMatcher
    Matches all arguments and their respective types for a CallExpr or
    CXXConstructExpr. It is very similar to forEachArgumentWithParam but
    it works on calls through function pointers as well.

    The difference is, that function pointers do not provide access to a
    ParmVarDecl, but only the QualType for each argument.

    Given
      void f(int i);
      int y;
      f(y);
      void (*f_ptr)(int) = f;
      f_ptr(y);
    callExpr(
      forEachArgumentWithParamType(
        declRefExpr(to(varDecl(hasName("y")))),
        qualType(isInteger()).bind("type)
    ))
      matches f(y) and f_ptr(y)
    with declRefExpr(...)
      matching int y
    and qualType(...)
      matching int
Matcher<CallExpr> | hasAnyArgument | Matcher<Expr> InnerMatcher
    Matches any argument of a call expression or a constructor call
    expression, or an ObjC-message-send expression.

    Given
      void x(int, int, int) { int y; x(1, y, 42); }
    callExpr(hasAnyArgument(declRefExpr()))
      matches x(1, y, 42)
    with hasAnyArgument(...)
      matching y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end
      void foo(I *i) { [i f:12]; }
    objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
      matches [i f:12]
Matcher<CallExpr> | hasArgument | unsigned N, Matcher<Expr> InnerMatcher
    Matches the n'th argument of a call expression or a constructor
    call expression.

    Example matches y in x(y)
        (matcher = callExpr(hasArgument(0, declRefExpr())))
      void x(int) { int y; x(y); }
Matcher<CallExpr> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<CaseStmt> | hasCaseConstant | Matcher<Expr> InnerMatcher
    If the given case statement does not use the GNU case range
    extension, matches the constant given in the statement.

    Given
      switch (1) { case 1: case 1+1: case 3 ... 4: ; }
    caseStmt(hasCaseConstant(integerLiteral()))
      matches "case 1:"
Matcher<CastExpr> | hasSourceExpression | Matcher<Expr> InnerMatcher
    Matches if the cast's source expression
    or opaque value's source expression matches the given matcher.

    Example 1: matches "a string"
    (matcher = castExpr(hasSourceExpression(cxxConstructExpr())))
    class URL { URL(string); };
    URL url = "a string";

    Example 2: matches 'b' (matcher =
    opaqueValueExpr(hasSourceExpression(implicitCastExpr(declRefExpr())))
    int a = b ?: 1;
Matcher<ClassTemplateSpecializationDecl> | hasAnyTemplateArgument | Matcher<TemplateArgument> InnerMatcher
    Matches classTemplateSpecializations, templateSpecializationType and
    functionDecl that have at least one TemplateArgument matching the given
    InnerMatcher.

    Given
      template<typename T> class A {};
      template<> class A<double> {};
      A<int> a;

      template<typename T> f() {};
      void func() { f<int>(); };

    classTemplateSpecializationDecl(hasAnyTemplateArgument(
        refersToType(asString("int"))))
      matches the specialization A<int>

    functionDecl(hasAnyTemplateArgument(refersToType(asString("int"))))
      matches the specialization f<int>
Matcher<ClassTemplateSpecializationDecl> | hasSpecializedTemplate | Matcher<ClassTemplateDecl> InnerMatcher
    Matches the specialized template of a specialization declaration.

    Given
      template<typename T> class A {}; #1
      template<> class A<int> {}; #2
    classTemplateSpecializationDecl(hasSpecializedTemplate(classTemplateDecl()))
      matches '#2' with classTemplateDecl() matching the class template
      declaration of 'A' at #1.
Matcher<ClassTemplateSpecializationDecl> | hasTemplateArgument | unsigned N, Matcher<TemplateArgument> InnerMatcher
    Matches classTemplateSpecializations, templateSpecializationType and
    functionDecl where the n'th TemplateArgument matches the given InnerMatcher.

    Given
      template<typename T, typename U> class A {};
      A<bool, int> b;
      A<int, bool> c;

      template<typename T> void f() {}
      void func() { f<int>(); };
    classTemplateSpecializationDecl(hasTemplateArgument(
        1, refersToType(asString("int"))))
      matches the specialization A<bool, int>

    functionDecl(hasTemplateArgument(0, refersToType(asString("int"))))
      matches the specialization f<int>
Matcher<ComplexType> | hasElementType | Matcher<Type>
    Matches arrays and C99 complex types that have a specific element
    type.

    Given
      struct A {};
      A a[7];
      int b[7];
    arrayType(hasElementType(builtinType()))
      matches "int b[7]"

    Usable as: Matcher<ArrayType>, Matcher<ComplexType>
Matcher<CompoundStmt> | hasAnySubstatement | Matcher<Stmt> InnerMatcher
    Matches compound statements where at least one substatement matches
    a given matcher. Also matches StmtExprs that have CompoundStmt as children.

    Given
      { {}; 1+2; }
    hasAnySubstatement(compoundStmt())
      matches '{ {}; 1+2; }'
    with compoundStmt()
      matching '{}'
Matcher<DecayedType> | hasDecayedType | Matcher<QualType> InnerType
    Matches the decayed type, whoes decayed type matches InnerMatcher
Matcher<DeclRefExpr> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<DeclRefExpr> | throughUsingDecl | Matcher<UsingShadowDecl> InnerMatcher
    Matches a DeclRefExpr that refers to a declaration through a
    specific using shadow declaration.

    Given
      namespace a { void f() {} }
      using a::f;
      void g() {
        f();     // Matches this ..
        a::f();  // .. but not this.
      }
    declRefExpr(throughUsingDecl(anything()))
      matches f()
Matcher<DeclRefExpr> | to | Matcher<Decl> InnerMatcher
    Matches a DeclRefExpr that refers to a declaration that matches the
    specified matcher.

    Example matches x in if(x)
        (matcher = declRefExpr(to(varDecl(hasName("x")))))
      bool x;
      if (x) {}
Matcher<DeclStmt> | containsDeclaration | unsigned N, Matcher<Decl> InnerMatcher
    Matches the n'th declaration of a declaration statement.

    Note that this does not work for global declarations because the AST
    breaks up multiple-declaration DeclStmt's into multiple single-declaration
    DeclStmt's.
    Example: Given non-global declarations
      int a, b = 0;
      int c;
      int d = 2, e;
    declStmt(containsDeclaration(
          0, varDecl(hasInitializer(anything()))))
      matches only 'int d = 2, e;', and
    declStmt(containsDeclaration(1, varDecl()))
      matches 'int a, b = 0' as well as 'int d = 2, e;'
      but 'int c;' is not matched.
Matcher<DeclStmt> | hasSingleDecl | Matcher<Decl> InnerMatcher
    Matches the Decl of a DeclStmt which has a single declaration.

    Given
      int a, b;
      int c;
    declStmt(hasSingleDecl(anything()))
      matches 'int c;' but not 'int a, b;'.
Matcher<DeclaratorDecl> | hasTypeLoc | Matcher<TypeLoc> Inner
    Matches if the type location of the declarator decl's type matches
    the inner matcher.

    Given
      int x;
    declaratorDecl(hasTypeLoc(loc(asString("int"))))
      matches int x
Matcher<Decl> | hasDeclContext | Matcher<Decl> InnerMatcher
    Matches declarations whose declaration context, interpreted as a
    Decl, matches InnerMatcher.

    Given
      namespace N {
        namespace M {
          class D {};
        }
      }

    cxxRcordDecl(hasDeclContext(namedDecl(hasName("M")))) matches the
    declaration of class D.
Matcher<DecltypeType> | hasUnderlyingType | Matcher<Type>
    Matches DecltypeType nodes to find out the underlying type.

    Given
      decltype(1) a = 1;
      decltype(2.0) b = 2.0;
    decltypeType(hasUnderlyingType(isInteger()))
      matches the type of "a"

    Usable as: Matcher<DecltypeType>
Matcher<DoStmt> | hasBody | Matcher<Stmt> InnerMatcher
Matcher<DoStmt> | hasCondition | Matcher<Expr> InnerMatcher
    Matches the condition expression of an if statement, for loop,
    switch statement or conditional operator.

    Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
      if (true) {}
Matcher<ElaboratedType> | hasQualifier | Matcher<NestedNameSpecifier> InnerMatcher
    Matches ElaboratedTypes whose qualifier, a NestedNameSpecifier,
    matches InnerMatcher if the qualifier exists.

    Given
      namespace N {
        namespace M {
          class D {};
        }
      }
      N::M::D d;

    elaboratedType(hasQualifier(hasPrefix(specifiesNamespace(hasName("N"))))
    matches the type of the variable declaration of d.
Matcher<ElaboratedType> | namesType | Matcher<QualType> InnerMatcher
    Matches ElaboratedTypes whose named type matches InnerMatcher.

    Given
      namespace N {
        namespace M {
          class D {};
        }
      }
      N::M::D d;

    elaboratedType(namesType(recordType(
    hasDeclaration(namedDecl(hasName("D")))))) matches the type of the variable
    declaration of d.
Matcher<EnumType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<ExplicitCastExpr> | hasDestinationType | Matcher<QualType> InnerMatcher
    Matches casts whose destination type matches a given matcher.

    (Note: Clang's AST refers to other conversions as "casts" too, and calls
    actual casts "explicit" casts.)
Matcher<Expr> | hasType | Matcher<Decl> InnerMatcher
    Overloaded to match the declaration of the expression's or value
    declaration's type.

    In case of a value declaration (for example a variable declaration),
    this resolves one layer of indirection. For example, in the value
    declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
    X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
    declaration of x.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     class Y { friend class X; };

    Example matches class Derived
    (matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
    class Base {};
    class Derived : Base {};

    Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
    Matcher<CXXBaseSpecifier>
Matcher<Expr> | hasType | Matcher<QualType> InnerMatcher
    Matches if the expression's or declaration's type matches a type
    matcher.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and U (matcher = typedefDecl(hasType(asString("int")))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     typedef int U;
     class Y { friend class X; };
Matcher<Expr> | ignoringElidableConstructorCall | ast_matchers::Matcher<Expr> InnerMatcher
    Matches expressions that match InnerMatcher that are possibly wrapped in an
    elidable constructor and other corresponding bookkeeping nodes.

    In C++17, elidable copy constructors are no longer being generated in the
    AST as it is not permitted by the standard. They are, however, part of the
    AST in C++14 and earlier. So, a matcher must abstract over these differences
    to work in all language modes. This matcher skips elidable constructor-call
    AST nodes, `ExprWithCleanups` nodes wrapping elidable constructor-calls and
    various implicit nodes inside the constructor calls, all of which will not
    appear in the C++17 AST.

    Given

    struct H {};
    H G();
    void f() {
      H D = G();
    }

    ``varDecl(hasInitializer(ignoringElidableConstructorCall(callExpr())))``
    matches ``H D = G()`` in C++11 through C++17 (and beyond).
Matcher<Expr> | ignoringImpCasts | Matcher<Expr> InnerMatcher
    Matches expressions that match InnerMatcher after any implicit casts
    are stripped off.

    Parentheses and explicit casts are not discarded.
    Given
      int arr[5];
      int a = 0;
      char b = 0;
      const int c = a;
      int *d = arr;
      long e = (long) 0l;
    The matchers
       varDecl(hasInitializer(ignoringImpCasts(integerLiteral())))
       varDecl(hasInitializer(ignoringImpCasts(declRefExpr())))
    would match the declarations for a, b, c, and d, but not e.
    While
       varDecl(hasInitializer(integerLiteral()))
       varDecl(hasInitializer(declRefExpr()))
    only match the declarations for b, c, and d.
Matcher<Expr> | ignoringImplicit | Matcher<Expr> InnerMatcher
    Matches expressions that match InnerMatcher after any implicit AST
    nodes are stripped off.

    Parentheses and explicit casts are not discarded.
    Given
      class C {};
      C a = C();
      C b;
      C c = b;
    The matchers
       varDecl(hasInitializer(ignoringImplicit(cxxConstructExpr())))
    would match the declarations for a, b, and c.
    While
       varDecl(hasInitializer(cxxConstructExpr()))
    only match the declarations for b and c.
Matcher<Expr> | ignoringParenCasts | Matcher<Expr> InnerMatcher
    Matches expressions that match InnerMatcher after parentheses and
    casts are stripped off.

    Implicit and non-C Style casts are also discarded.
    Given
      int a = 0;
      char b = (0);
      void* c = reinterpret_cast<char*>(0);
      char d = char(0);
    The matcher
       varDecl(hasInitializer(ignoringParenCasts(integerLiteral())))
    would match the declarations for a, b, c, and d.
    while
       varDecl(hasInitializer(integerLiteral()))
    only match the declaration for a.
Matcher<Expr> | ignoringParenImpCasts | Matcher<Expr> InnerMatcher
    Matches expressions that match InnerMatcher after implicit casts and
    parentheses are stripped off.

    Explicit casts are not discarded.
    Given
      int arr[5];
      int a = 0;
      char b = (0);
      const int c = a;
      int *d = (arr);
      long e = ((long) 0l);
    The matchers
       varDecl(hasInitializer(ignoringParenImpCasts(integerLiteral())))
       varDecl(hasInitializer(ignoringParenImpCasts(declRefExpr())))
    would match the declarations for a, b, c, and d, but not e.
    while
       varDecl(hasInitializer(integerLiteral()))
       varDecl(hasInitializer(declRefExpr()))
    would only match the declaration for a.
Matcher<Expr> | ignoringParens | Matcher<Expr> InnerMatcher
    Overload ignoringParens for Expr.

    Given
      const char* str = ("my-string");
    The matcher
      implicitCastExpr(hasSourceExpression(ignoringParens(stringLiteral())))
    would match the implicit cast resulting from the assignment.
Matcher<FieldDecl> | hasInClassInitializer | Matcher<Expr> InnerMatcher
    Matches non-static data members that have an in-class initializer.

    Given
      class C {
        int a = 2;
        int b = 3;
        int c;
      };
    fieldDecl(hasInClassInitializer(integerLiteral(equals(2))))
      matches 'int a;' but not 'int b;'.
    fieldDecl(hasInClassInitializer(anything()))
      matches 'int a;' and 'int b;' but not 'int c;'.
Matcher<ForStmt> | hasBody | Matcher<Stmt> InnerMatcher
Matcher<ForStmt> | hasCondition | Matcher<Expr> InnerMatcher
    Matches the condition expression of an if statement, for loop,
    switch statement or conditional operator.

    Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
      if (true) {}
Matcher<ForStmt> | hasIncrement | Matcher<Stmt> InnerMatcher
    Matches the increment statement of a for loop.

    Example:
        forStmt(hasIncrement(unaryOperator(hasOperatorName("++"))))
    matches '++x' in
        for (x; x < N; ++x) { }
Matcher<ForStmt> | hasLoopInit | Matcher<Stmt> InnerMatcher
    Matches the initialization statement of a for loop.

    Example:
        forStmt(hasLoopInit(declStmt()))
    matches 'int x = 0' in
        for (int x = 0; x < N; ++x) { }
Matcher<FriendDecl> | hasType | Matcher<Decl> InnerMatcher
    Overloaded to match the declaration of the expression's or value
    declaration's type.

    In case of a value declaration (for example a variable declaration),
    this resolves one layer of indirection. For example, in the value
    declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
    X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
    declaration of x.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     class Y { friend class X; };

    Example matches class Derived
    (matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
    class Base {};
    class Derived : Base {};

    Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
    Matcher<CXXBaseSpecifier>
Matcher<FriendDecl> | hasType | Matcher<QualType> InnerMatcher
    Matches if the expression's or declaration's type matches a type
    matcher.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and U (matcher = typedefDecl(hasType(asString("int")))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     typedef int U;
     class Y { friend class X; };
Matcher<FunctionDecl> | hasAnyBody | Matcher<Stmt> InnerMatcher
    Matches a function declaration that has a given body present in the AST.
    Note that this matcher matches all the declarations of a function whose
    body is present in the AST.

    Given
      void f();
      void f() {}
      void g();
    hasAnyBody(functionDecl())
      matches both 'void f();'
      and 'void f() {}'
    with compoundStmt()
      matching '{}'
      but does not match 'void g();'
Matcher<FunctionDecl> | hasAnyParameter | Matcher<ParmVarDecl> InnerMatcher
    Matches any parameter of a function or an ObjC method declaration or a
    block.

    Does not match the 'this' parameter of a method.

    Given
      class X { void f(int x, int y, int z) {} };
    cxxMethodDecl(hasAnyParameter(hasName("y")))
      matches f(int x, int y, int z) {}
    with hasAnyParameter(...)
      matching int y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end

    the matcher objcMethodDecl(hasAnyParameter(hasName("y")))
    matches the declaration of method f with hasParameter
    matching y.

    For blocks, given
      b = ^(int y) { printf("%d", y) };

    the matcher blockDecl(hasAnyParameter(hasName("y")))
    matches the declaration of the block b with hasParameter
    matching y.
Matcher<FunctionDecl> | hasAnyTemplateArgument | Matcher<TemplateArgument> InnerMatcher
    Matches classTemplateSpecializations, templateSpecializationType and
    functionDecl that have at least one TemplateArgument matching the given
    InnerMatcher.

    Given
      template<typename T> class A {};
      template<> class A<double> {};
      A<int> a;

      template<typename T> f() {};
      void func() { f<int>(); };

    classTemplateSpecializationDecl(hasAnyTemplateArgument(
        refersToType(asString("int"))))
      matches the specialization A<int>

    functionDecl(hasAnyTemplateArgument(refersToType(asString("int"))))
      matches the specialization f<int>
Matcher<FunctionDecl> | hasBody | Matcher<Stmt> InnerMatcher
Matcher<FunctionDecl> | hasExplicitSpecifier | Matcher<Expr> InnerMatcher
    Matches the expression in an explicit specifier if present in the given
    declaration.

    Given
      template<bool b>
      struct S {
        S(int); // #1
        explicit S(double); // #2
        operator int(); // #3
        explicit operator bool(); // #4
        explicit(false) S(bool) // # 7
        explicit(true) S(char) // # 8
        explicit(b) S(S) // # 9
      };
      S(int) -> S<true> // #5
      explicit S(double) -> S<false> // #6
    cxxConstructorDecl(hasExplicitSpecifier(constantExpr())) will match #7, #8 and #9, but not #1 or #2.
    cxxConversionDecl(hasExplicitSpecifier(constantExpr())) will not match #3 or #4.
    cxxDeductionGuideDecl(hasExplicitSpecifier(constantExpr())) will not match #5 or #6.
Matcher<FunctionDecl> | hasParameter | unsigned N, Matcher<ParmVarDecl> InnerMatcher
    Matches the n'th parameter of a function or an ObjC method
    declaration or a block.

    Given
      class X { void f(int x) {} };
    cxxMethodDecl(hasParameter(0, hasType(varDecl())))
      matches f(int x) {}
    with hasParameter(...)
      matching int x

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end

    the matcher objcMethodDecl(hasParameter(0, hasName("y")))
    matches the declaration of method f with hasParameter
    matching y.
Matcher<FunctionDecl> | hasTemplateArgument | unsigned N, Matcher<TemplateArgument> InnerMatcher
    Matches classTemplateSpecializations, templateSpecializationType and
    functionDecl where the n'th TemplateArgument matches the given InnerMatcher.

    Given
      template<typename T, typename U> class A {};
      A<bool, int> b;
      A<int, bool> c;

      template<typename T> void f() {}
      void func() { f<int>(); };
    classTemplateSpecializationDecl(hasTemplateArgument(
        1, refersToType(asString("int"))))
      matches the specialization A<bool, int>

    functionDecl(hasTemplateArgument(0, refersToType(asString("int"))))
      matches the specialization f<int>
Matcher<FunctionDecl> | returns | Matcher<QualType> InnerMatcher
    Matches the return type of a function declaration.

    Given:
      class X { int f() { return 1; } };
    cxxMethodDecl(returns(asString("int")))
      matches int f() { return 1; }
Matcher<IfStmt> | hasCondition | Matcher<Expr> InnerMatcher
    Matches the condition expression of an if statement, for loop,
    switch statement or conditional operator.

    Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
      if (true) {}
Matcher<IfStmt> | hasConditionVariableStatement | Matcher<DeclStmt> InnerMatcher
    Matches the condition variable statement in an if statement.

    Given
      if (A* a = GetAPointer()) {}
    hasConditionVariableStatement(...)
      matches 'A* a = GetAPointer()'.
Matcher<IfStmt> | hasElse | Matcher<Stmt> InnerMatcher
    Matches the else-statement of an if statement.

    Examples matches the if statement
      (matcher = ifStmt(hasElse(cxxBoolLiteral(equals(true)))))
      if (false) false; else true;
Matcher<IfStmt> | hasInitStatement | Matcher<Stmt> InnerMatcher
    Matches selection statements with initializer.

    Given:
     void foo() {
       if (int i = foobar(); i > 0) {}
       switch (int i = foobar(); i) {}
       for (auto& a = get_range(); auto& x : a) {}
     }
     void bar() {
       if (foobar() > 0) {}
       switch (foobar()) {}
       for (auto& x : get_range()) {}
     }
    ifStmt(hasInitStatement(anything()))
      matches the if statement in foo but not in bar.
    switchStmt(hasInitStatement(anything()))
      matches the switch statement in foo but not in bar.
    cxxForRangeStmt(hasInitStatement(anything()))
      matches the range for statement in foo but not in bar.
Matcher<IfStmt> | hasThen | Matcher<Stmt> InnerMatcher
    Matches the then-statement of an if statement.

    Examples matches the if statement
      (matcher = ifStmt(hasThen(cxxBoolLiteral(equals(true)))))
      if (false) true; else false;
Matcher<ImplicitCastExpr> | hasImplicitDestinationType | Matcher<QualType> InnerMatcher
    Matches implicit casts whose destination type matches a given
    matcher.

    FIXME: Unit test this matcher
Matcher<InitListExpr> | hasInit | unsigned N, ast_matchers::Matcher<Expr> InnerMatcher
    Matches the n'th item of an initializer list expression.

    Example matches y.
        (matcher = initListExpr(hasInit(0, expr())))
      int x{y}.
Matcher<InitListExpr> | hasSyntacticForm | Matcher<Expr> InnerMatcher
    Matches the syntactic form of init list expressions
    (if expression have it).
Matcher<InjectedClassNameType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<LabelStmt> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<LambdaExpr> | hasAnyCapture | Matcher<CXXThisExpr> InnerMatcher
    Matches any capture of 'this' in a lambda expression.

    Given
      struct foo {
        void bar() {
          auto f = [this](){};
        }
      }
    lambdaExpr(hasAnyCapture(cxxThisExpr()))
      matches [this](){};
Matcher<LambdaExpr> | hasAnyCapture | Matcher<VarDecl> InnerMatcher
    Matches any capture of a lambda expression.

    Given
      void foo() {
        int x;
        auto f = [x](){};
      }
    lambdaExpr(hasAnyCapture(anything()))
      matches [x](){};
Matcher<MemberExpr> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<MemberExpr> | hasObjectExpression | Matcher<Expr> InnerMatcher
    Matches a member expression where the object expression is matched by a
    given matcher. Implicit object expressions are included; that is, it matches
    use of implicit `this`.

    Given
      struct X {
        int m;
        int f(X x) { x.m; return m; }
      };
    memberExpr(hasObjectExpression(hasType(cxxRecordDecl(hasName("X")))))
      matches `x.m`, but not `m`; however,
    memberExpr(hasObjectExpression(hasType(pointsTo(
         cxxRecordDecl(hasName("X"))))))
      matches `m` (aka. `this->m`), but not `x.m`.
Matcher<MemberExpr> | member | Matcher<ValueDecl> InnerMatcher
    Matches a member expression where the member is matched by a
    given matcher.

    Given
      struct { int first, second; } first, second;
      int i(second.first);
      int j(first.second);
    memberExpr(member(hasName("first")))
      matches second.first
      but not first.second (because the member name there is "second").
Matcher<MemberPointerType> | pointee | Matcher<Type>
    Narrows PointerType (and similar) matchers to those where the
    pointee matches a given matcher.

    Given
      int *a;
      int const *b;
      float const *f;
    pointerType(pointee(isConstQualified(), isInteger()))
      matches "int const *b"

    Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
      Matcher<PointerType>, Matcher<ReferenceType>
Matcher<NamedDecl> | hasUnderlyingDecl | Matcher<NamedDecl> InnerMatcher
    Matches a NamedDecl whose underlying declaration matches the given
    matcher.

    Given
      namespace N { template<class T> void f(T t); }
      template <class T> void g() { using N::f; f(T()); }
    unresolvedLookupExpr(hasAnyDeclaration(
        namedDecl(hasUnderlyingDecl(hasName("::N::f")))))
      matches the use of f in g() .
Matcher<NestedNameSpecifierLoc> | hasPrefix | Matcher<NestedNameSpecifierLoc> InnerMatcher
    Matches on the prefix of a NestedNameSpecifierLoc.

    Given
      struct A { struct B { struct C {}; }; };
      A::B::C c;
    nestedNameSpecifierLoc(hasPrefix(loc(specifiesType(asString("struct A")))))
      matches "A::"
Matcher<NestedNameSpecifierLoc> | loc | Matcher<NestedNameSpecifier> InnerMatcher
    Matches NestedNameSpecifierLocs for which the given inner
    NestedNameSpecifier-matcher matches.
Matcher<NestedNameSpecifierLoc> | specifiesTypeLoc | Matcher<TypeLoc> InnerMatcher
    Matches nested name specifier locs that specify a type matching the
    given TypeLoc.

    Given
      struct A { struct B { struct C {}; }; };
      A::B::C c;
    nestedNameSpecifierLoc(specifiesTypeLoc(loc(type(
      hasDeclaration(cxxRecordDecl(hasName("A")))))))
      matches "A::"
Matcher<NestedNameSpecifier> | hasPrefix | Matcher<NestedNameSpecifier> InnerMatcher
    Matches on the prefix of a NestedNameSpecifier.

    Given
      struct A { struct B { struct C {}; }; };
      A::B::C c;
    nestedNameSpecifier(hasPrefix(specifiesType(asString("struct A")))) and
      matches "A::"
Matcher<NestedNameSpecifier> | specifiesNamespace | Matcher<NamespaceDecl> InnerMatcher
    Matches nested name specifiers that specify a namespace matching the
    given namespace matcher.

    Given
      namespace ns { struct A {}; }
      ns::A a;
    nestedNameSpecifier(specifiesNamespace(hasName("ns")))
      matches "ns::"
Matcher<NestedNameSpecifier> | specifiesType | Matcher<QualType> InnerMatcher
    Matches nested name specifiers that specify a type matching the
    given QualType matcher without qualifiers.

    Given
      struct A { struct B { struct C {}; }; };
      A::B::C c;
    nestedNameSpecifier(specifiesType(
      hasDeclaration(cxxRecordDecl(hasName("A")))
    ))
      matches "A::"
Matcher<OMPExecutableDirective> | hasAnyClause | Matcher<OMPClause> InnerMatcher
    Matches any clause in an OpenMP directive.

    Given

      #pragma omp parallel
      #pragma omp parallel default(none)

    ``ompExecutableDirective(hasAnyClause(anything()))`` matches
    ``omp parallel default(none)``.
Matcher<OMPExecutableDirective> | hasStructuredBlock | Matcher<Stmt> InnerMatcher
    Matches the structured-block of the OpenMP executable directive

    Prerequisite: the executable directive must not be standalone directive.
    If it is, it will never match.

    Given

       #pragma omp parallel
       ;
       #pragma omp parallel
       {}

    ``ompExecutableDirective(hasStructuredBlock(nullStmt()))`` will match ``;``
Matcher<ObjCInterfaceDecl> | isDerivedFrom | Matcher<NamedDecl> Base
    Matches C++ classes that are directly or indirectly derived from a class
    matching Base, or Objective-C classes that directly or indirectly
    subclass a class matching Base.

    Note that a class is not considered to be derived from itself.

    Example matches Y, Z, C (Base == hasName("X"))
      class X;
      class Y : public X {};  // directly derived
      class Z : public Y {};  // indirectly derived
      typedef X A;
      typedef A B;
      class C : public B {};  // derived from a typedef of X

    In the following example, Bar matches isDerivedFrom(hasName("X")):
      class Foo;
      typedef Foo X;
      class Bar : public Foo {};  // derived from a type that X is a typedef of

    In the following example, Bar matches isDerivedFrom(hasName("NSObject"))
      @interface NSObject @end
      @interface Bar : NSObject @end

    Usable as: Matcher<CXXRecordDecl>, Matcher<ObjCInterfaceDecl>
Matcher<ObjCInterfaceDecl> | isDirectlyDerivedFrom | Matcher<NamedDecl> Base
    Matches C++ or Objective-C classes that are directly derived from a class
    matching Base.

    Note that a class is not considered to be derived from itself.

    Example matches Y, C (Base == hasName("X"))
      class X;
      class Y : public X {};  // directly derived
      class Z : public Y {};  // indirectly derived
      typedef X A;
      typedef A B;
      class C : public B {};  // derived from a typedef of X

    In the following example, Bar matches isDerivedFrom(hasName("X")):
      class Foo;
      typedef Foo X;
      class Bar : public Foo {};  // derived from a type that X is a typedef of
Matcher<ObjCInterfaceDecl> | isSameOrDerivedFrom | Matcher<NamedDecl> Base
    Similar to isDerivedFrom(), but also matches classes that directly
    match Base.
Matcher<ObjCMessageExpr> | hasAnyArgument | Matcher<Expr> InnerMatcher
    Matches any argument of a call expression or a constructor call
    expression, or an ObjC-message-send expression.

    Given
      void x(int, int, int) { int y; x(1, y, 42); }
    callExpr(hasAnyArgument(declRefExpr()))
      matches x(1, y, 42)
    with hasAnyArgument(...)
      matching y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end
      void foo(I *i) { [i f:12]; }
    objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
      matches [i f:12]
Matcher<ObjCMessageExpr> | hasArgument | unsigned N, Matcher<Expr> InnerMatcher
    Matches the n'th argument of a call expression or a constructor
    call expression.

    Example matches y in x(y)
        (matcher = callExpr(hasArgument(0, declRefExpr())))
      void x(int) { int y; x(y); }
Matcher<ObjCMessageExpr> | hasReceiver | Matcher<Expr> InnerMatcher
    Matches if the Objective-C message is sent to an instance,
    and the inner matcher matches on that instance.

    For example the method call in
      NSString *x = @"hello";
      [x containsString:@"h"];
    is matched by
    objcMessageExpr(hasReceiver(declRefExpr(to(varDecl(hasName("x"))))))
Matcher<ObjCMessageExpr> | hasReceiverType | Matcher<QualType> InnerMatcher
    Matches on the receiver of an ObjectiveC Message expression.

    Example
    matcher = objCMessageExpr(hasReceiverType(asString("UIWebView *")));
    matches the [webView ...] message invocation.
      NSString *webViewJavaScript = ...
      UIWebView *webView = ...
      [webView stringByEvaluatingJavaScriptFromString:webViewJavascript];
Matcher<ObjCMethodDecl> | hasAnyParameter | Matcher<ParmVarDecl> InnerMatcher
    Matches any parameter of a function or an ObjC method declaration or a
    block.

    Does not match the 'this' parameter of a method.

    Given
      class X { void f(int x, int y, int z) {} };
    cxxMethodDecl(hasAnyParameter(hasName("y")))
      matches f(int x, int y, int z) {}
    with hasAnyParameter(...)
      matching int y

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end

    the matcher objcMethodDecl(hasAnyParameter(hasName("y")))
    matches the declaration of method f with hasParameter
    matching y.

    For blocks, given
      b = ^(int y) { printf("%d", y) };

    the matcher blockDecl(hasAnyParameter(hasName("y")))
    matches the declaration of the block b with hasParameter
    matching y.
Matcher<ObjCMethodDecl> | hasParameter | unsigned N, Matcher<ParmVarDecl> InnerMatcher
    Matches the n'th parameter of a function or an ObjC method
    declaration or a block.

    Given
      class X { void f(int x) {} };
    cxxMethodDecl(hasParameter(0, hasType(varDecl())))
      matches f(int x) {}
    with hasParameter(...)
      matching int x

    For ObjectiveC, given
      @interface I - (void) f:(int) y; @end

    the matcher objcMethodDecl(hasParameter(0, hasName("y")))
    matches the declaration of method f with hasParameter
    matching y.
Matcher<OpaqueValueExpr> | hasSourceExpression | Matcher<Expr> InnerMatcher
    Matches if the cast's source expression
    or opaque value's source expression matches the given matcher.

    Example 1: matches "a string"
    (matcher = castExpr(hasSourceExpression(cxxConstructExpr())))
    class URL { URL(string); };
    URL url = "a string";

    Example 2: matches 'b' (matcher =
    opaqueValueExpr(hasSourceExpression(implicitCastExpr(declRefExpr())))
    int a = b ?: 1;
Matcher<OverloadExpr> | hasAnyDeclaration | Matcher<Decl> InnerMatcher
    Matches an OverloadExpr if any of the declarations in the set of
    overloads matches the given matcher.

    Given
      template <typename T> void foo(T);
      template <typename T> void bar(T);
      template <typename T> void baz(T t) {
        foo(t);
        bar(t);
      }
    unresolvedLookupExpr(hasAnyDeclaration(
        functionTemplateDecl(hasName("foo"))))
      matches foo in foo(t); but not bar in bar(t);
Matcher<ParenType> | innerType | Matcher<Type>
    Matches ParenType nodes where the inner type is a specific type.

    Given
      int (*ptr_to_array)[4];
      int (*ptr_to_func)(int);

    varDecl(hasType(pointsTo(parenType(innerType(functionType()))))) matches
    ptr_to_func but not ptr_to_array.

    Usable as: Matcher<ParenType>
Matcher<PointerType> | pointee | Matcher<Type>
    Narrows PointerType (and similar) matchers to those where the
    pointee matches a given matcher.

    Given
      int *a;
      int const *b;
      float const *f;
    pointerType(pointee(isConstQualified(), isInteger()))
      matches "int const *b"

    Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
      Matcher<PointerType>, Matcher<ReferenceType>
Matcher<QualType> | hasCanonicalType | Matcher<QualType> InnerMatcher
    Matches QualTypes whose canonical type matches InnerMatcher.

    Given:
      typedef int &int_ref;
      int a;
      int_ref b = a;

    varDecl(hasType(qualType(referenceType()))))) will not match the
    declaration of b but varDecl(hasType(qualType(hasCanonicalType(referenceType())))))) does.
Matcher<QualType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<QualType> | ignoringParens | Matcher<QualType> InnerMatcher
    Matches types that match InnerMatcher after any parens are stripped.

    Given
      void (*fp)(void);
    The matcher
      varDecl(hasType(pointerType(pointee(ignoringParens(functionType())))))
    would match the declaration for fp.
Matcher<QualType> | pointsTo | Matcher<Decl> InnerMatcher
    Overloaded to match the pointee type's declaration.
Matcher<QualType> | pointsTo | Matcher<QualType> InnerMatcher
    Matches if the matched type is a pointer type and the pointee type
    matches the specified matcher.

    Example matches y->x()
      (matcher = cxxMemberCallExpr(on(hasType(pointsTo
         cxxRecordDecl(hasName("Y")))))))
      class Y { public: void x(); };
      void z() { Y *y; y->x(); }
Matcher<QualType> | references | Matcher<Decl> InnerMatcher
    Overloaded to match the referenced type's declaration.
Matcher<QualType> | references | Matcher<QualType> InnerMatcher
    Matches if the matched type is a reference type and the referenced
    type matches the specified matcher.

    Example matches X &x and const X &y
        (matcher = varDecl(hasType(references(cxxRecordDecl(hasName("X"))))))
      class X {
        void a(X b) {
          X &x = b;
          const X &y = b;
        }
      };
Matcher<RecordType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<ReferenceType> | pointee | Matcher<Type>
    Narrows PointerType (and similar) matchers to those where the
    pointee matches a given matcher.

    Given
      int *a;
      int const *b;
      float const *f;
    pointerType(pointee(isConstQualified(), isInteger()))
      matches "int const *b"

    Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
      Matcher<PointerType>, Matcher<ReferenceType>
Matcher<ReturnStmt> | hasReturnValue | Matcher<Expr> InnerMatcher
    Matches the return value expression of a return statement

    Given
      return a + b;
    hasReturnValue(binaryOperator())
      matches 'return a + b'
    with binaryOperator()
      matching 'a + b'
Matcher<StmtExpr> | hasAnySubstatement | Matcher<Stmt> InnerMatcher
    Matches compound statements where at least one substatement matches
    a given matcher. Also matches StmtExprs that have CompoundStmt as children.

    Given
      { {}; 1+2; }
    hasAnySubstatement(compoundStmt())
      matches '{ {}; 1+2; }'
    with compoundStmt()
      matching '{}'
Matcher<Stmt> | alignOfExpr | Matcher<UnaryExprOrTypeTraitExpr> InnerMatcher
    Same as unaryExprOrTypeTraitExpr, but only matching
    alignof.
Matcher<Stmt> | forFunction | Matcher<FunctionDecl> InnerMatcher
    Matches declaration of the function the statement belongs to

    Given:
    F& operator=(const F& o) {
      std::copy_if(o.begin(), o.end(), begin(), [](V v) { return v > 0; });
      return *this;
    }
    returnStmt(forFunction(hasName("operator=")))
      matches 'return *this'
      but does not match 'return v > 0'
Matcher<Stmt> | sizeOfExpr | Matcher<UnaryExprOrTypeTraitExpr> InnerMatcher
    Same as unaryExprOrTypeTraitExpr, but only matching
    sizeof.
Matcher<SubstTemplateTypeParmType> | hasReplacementType | Matcher<Type>
    Matches template type parameter substitutions that have a replacement
    type that matches the provided matcher.

    Given
      template <typename T>
      double F(T t);
      int i;
      double j = F(i);

    substTemplateTypeParmType(hasReplacementType(type())) matches int
Matcher<SwitchStmt> | forEachSwitchCase | Matcher<SwitchCase> InnerMatcher
    Matches each case or default statement belonging to the given switch
    statement. This matcher may produce multiple matches.

    Given
      switch (1) { case 1: case 2: default: switch (2) { case 3: case 4: ; } }
    switchStmt(forEachSwitchCase(caseStmt().bind("c"))).bind("s")
      matches four times, with "c" binding each of "case 1:", "case 2:",
    "case 3:" and "case 4:", and "s" respectively binding "switch (1)",
    "switch (1)", "switch (2)" and "switch (2)".
Matcher<SwitchStmt> | hasCondition | Matcher<Expr> InnerMatcher
    Matches the condition expression of an if statement, for loop,
    switch statement or conditional operator.

    Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
      if (true) {}
Matcher<SwitchStmt> | hasInitStatement | Matcher<Stmt> InnerMatcher
    Matches selection statements with initializer.

    Given:
     void foo() {
       if (int i = foobar(); i > 0) {}
       switch (int i = foobar(); i) {}
       for (auto& a = get_range(); auto& x : a) {}
     }
     void bar() {
       if (foobar() > 0) {}
       switch (foobar()) {}
       for (auto& x : get_range()) {}
     }
    ifStmt(hasInitStatement(anything()))
      matches the if statement in foo but not in bar.
    switchStmt(hasInitStatement(anything()))
      matches the switch statement in foo but not in bar.
    cxxForRangeStmt(hasInitStatement(anything()))
      matches the range for statement in foo but not in bar.
Matcher<TagType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<TemplateArgument> | isExpr | Matcher<Expr> InnerMatcher
    Matches a sugar TemplateArgument that refers to a certain expression.

    Given
      struct B { int next; };
      template<int(B::*next_ptr)> struct A {};
      A<&B::next> a;
    templateSpecializationType(hasAnyTemplateArgument(
      isExpr(hasDescendant(declRefExpr(to(fieldDecl(hasName("next"))))))))
      matches the specialization A<&B::next> with fieldDecl(...) matching
        B::next
Matcher<TemplateArgument> | refersToDeclaration | Matcher<Decl> InnerMatcher
    Matches a canonical TemplateArgument that refers to a certain
    declaration.

    Given
      struct B { int next; };
      template<int(B::*next_ptr)> struct A {};
      A<&B::next> a;
    classTemplateSpecializationDecl(hasAnyTemplateArgument(
        refersToDeclaration(fieldDecl(hasName("next")))))
      matches the specialization A<&B::next> with fieldDecl(...) matching
        B::next
Matcher<TemplateArgument> | refersToIntegralType | Matcher<QualType> InnerMatcher
    Matches a TemplateArgument that refers to an integral type.

    Given
      template<int T> struct C {};
      C<42> c;
    classTemplateSpecializationDecl(
      hasAnyTemplateArgument(refersToIntegralType(asString("int"))))
      matches the implicit instantiation of C in C<42>.
Matcher<TemplateArgument> | refersToTemplate | Matcher<TemplateName> InnerMatcher
    Matches a TemplateArgument that refers to a certain template.

    Given
      template<template <typename> class S> class X {};
      template<typename T> class Y {};
      X<Y> xi;
    classTemplateSpecializationDecl(hasAnyTemplateArgument(
        refersToTemplate(templateName())))
      matches the specialization X<Y>
Matcher<TemplateArgument> | refersToType | Matcher<QualType> InnerMatcher
    Matches a TemplateArgument that refers to a certain type.

    Given
      struct X {};
      template<typename T> struct A {};
      A<X> a;
    classTemplateSpecializationDecl(hasAnyTemplateArgument(
        refersToType(class(hasName("X")))))
      matches the specialization A<X>
Matcher<TemplateSpecializationType> | hasAnyTemplateArgument | Matcher<TemplateArgument> InnerMatcher
    Matches classTemplateSpecializations, templateSpecializationType and
    functionDecl that have at least one TemplateArgument matching the given
    InnerMatcher.

    Given
      template<typename T> class A {};
      template<> class A<double> {};
      A<int> a;

      template<typename T> f() {};
      void func() { f<int>(); };

    classTemplateSpecializationDecl(hasAnyTemplateArgument(
        refersToType(asString("int"))))
      matches the specialization A<int>

    functionDecl(hasAnyTemplateArgument(refersToType(asString("int"))))
      matches the specialization f<int>
Matcher<TemplateSpecializationType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<TemplateSpecializationType> | hasTemplateArgument | unsigned N, Matcher<TemplateArgument> InnerMatcher
    Matches classTemplateSpecializations, templateSpecializationType and
    functionDecl where the n'th TemplateArgument matches the given InnerMatcher.

    Given
      template<typename T, typename U> class A {};
      A<bool, int> b;
      A<int, bool> c;

      template<typename T> void f() {}
      void func() { f<int>(); };
    classTemplateSpecializationDecl(hasTemplateArgument(
        1, refersToType(asString("int"))))
      matches the specialization A<bool, int>

    functionDecl(hasTemplateArgument(0, refersToType(asString("int"))))
      matches the specialization f<int>
Matcher<TemplateTypeParmType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<TypeLoc> | loc | Matcher<QualType> InnerMatcher
    Matches TypeLocs for which the given inner
    QualType-matcher matches.
Matcher<TypedefNameDecl> | hasType | Matcher<QualType> InnerMatcher
    Matches if the expression's or declaration's type matches a type
    matcher.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and U (matcher = typedefDecl(hasType(asString("int")))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     typedef int U;
     class Y { friend class X; };
Matcher<TypedefType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<Type> | hasUnqualifiedDesugaredType | Matcher<Type> InnerMatcher
    Matches if the matched type matches the unqualified desugared
    type of the matched node.

    For example, in:
      class A {};
      using B = A;
    The matcher type(hasUnqualifiedDesugaredType(recordType())) matches
    both B and A.
Matcher<UnaryExprOrTypeTraitExpr> | hasArgumentOfType | Matcher<QualType> InnerMatcher
    Matches unary expressions that have a specific type of argument.

    Given
      int a, c; float b; int s = sizeof(a) + sizeof(b) + alignof(c);
    unaryExprOrTypeTraitExpr(hasArgumentOfType(asString("int"))
      matches sizeof(a) and alignof(c)
Matcher<UnaryOperator> | hasUnaryOperand | Matcher<Expr> InnerMatcher
    Matches if the operand of a unary operator matches.

    Example matches true (matcher = hasUnaryOperand(
                                      cxxBoolLiteral(equals(true))))
      !true
Matcher<UnresolvedMemberExpr> | hasObjectExpression | Matcher<Expr> InnerMatcher
    Matches a member expression where the object expression is matched by a
    given matcher. Implicit object expressions are included; that is, it matches
    use of implicit `this`.

    Given
      struct X {
        int m;
        int f(X x) { x.m; return m; }
      };
    memberExpr(hasObjectExpression(hasType(cxxRecordDecl(hasName("X")))))
      matches `x.m`, but not `m`; however,
    memberExpr(hasObjectExpression(hasType(pointsTo(
         cxxRecordDecl(hasName("X"))))))
      matches `m` (aka. `this->m`), but not `x.m`.
Matcher<UnresolvedUsingType> | hasDeclaration | Matcher<Decl> InnerMatcher
    Matches a node if the declaration associated with that node
    matches the given matcher.

    The associated declaration is:
    - for type nodes, the declaration of the underlying type
    - for CallExpr, the declaration of the callee
    - for MemberExpr, the declaration of the referenced member
    - for CXXConstructExpr, the declaration of the constructor
    - for CXXNewExpr, the declaration of the operator new
    - for ObjCIvarExpr, the declaration of the ivar

    For type nodes, hasDeclaration will generally match the declaration of the
    sugared type. Given
      class X {};
      typedef X Y;
      Y y;
    in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
    typedefDecl. A common use case is to match the underlying, desugared type.
    This can be achieved by using the hasUnqualifiedDesugaredType matcher:
      varDecl(hasType(hasUnqualifiedDesugaredType(
          recordType(hasDeclaration(decl())))))
    In this matcher, the decl will match the CXXRecordDecl of class X.

    Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
      Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
      Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
      Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
      Matcher<TagType>, Matcher<TemplateSpecializationType>,
      Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
      Matcher<UnresolvedUsingType>
Matcher<UsingDecl> | hasAnyUsingShadowDecl | Matcher<UsingShadowDecl> InnerMatcher
    Matches any using shadow declaration.

    Given
      namespace X { void b(); }
      using X::b;
    usingDecl(hasAnyUsingShadowDecl(hasName("b"))))
      matches using X::b
Matcher<UsingShadowDecl> | hasTargetDecl | Matcher<NamedDecl> InnerMatcher
    Matches a using shadow declaration where the target declaration is
    matched by the given matcher.

    Given
      namespace X { int a; void b(); }
      using X::a;
      using X::b;
    usingDecl(hasAnyUsingShadowDecl(hasTargetDecl(functionDecl())))
      matches using X::b but not using X::a
Matcher<ValueDecl> | hasType | Matcher<Decl> InnerMatcher
    Overloaded to match the declaration of the expression's or value
    declaration's type.

    In case of a value declaration (for example a variable declaration),
    this resolves one layer of indirection. For example, in the value
    declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
    X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
    declaration of x.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     class Y { friend class X; };

    Example matches class Derived
    (matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
    class Base {};
    class Derived : Base {};

    Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
    Matcher<CXXBaseSpecifier>
Matcher<ValueDecl> | hasType | Matcher<QualType> InnerMatcher
    Matches if the expression's or declaration's type matches a type
    matcher.

    Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
                and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
                and U (matcher = typedefDecl(hasType(asString("int")))
                and friend class X (matcher = friendDecl(hasType("X"))
     class X {};
     void y(X &x) { x; X z; }
     typedef int U;
     class Y { friend class X; };
Matcher<VarDecl> | hasInitializer | Matcher<Expr> InnerMatcher
    Matches a variable declaration that has an initializer expression
    that matches the given matcher.

    Example matches x (matcher = varDecl(hasInitializer(callExpr())))
      bool y() { return true; }
      bool x = y();
Matcher<VariableArrayType> | hasSizeExpr | Matcher<Expr> InnerMatcher
    Matches VariableArrayType nodes that have a specific size
    expression.

    Given
      void f(int b) {
        int a[b];
      }
    variableArrayType(hasSizeExpr(ignoringImpCasts(declRefExpr(to(
      varDecl(hasName("b")))))))
      matches "int a[b]"
Matcher<WhileStmt> | hasBody | Matcher<Stmt> InnerMatcher
Matcher<WhileStmt> | hasCondition | Matcher<Expr> InnerMatcher
    Matches the condition expression of an if statement, for loop,
    switch statement or conditional operator.

    Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
      if (true) {}