[Clang][ASTMatcher] Add dependentTemplateSpecializationType matcher (#121435)

Fixes https://github.com/llvm/llvm-project/issues/121307

clang/docs/LibASTMatchersReference.html

@@ -2546,6 +2546,17 @@ Example matches T::type
   };
 </pre></td></tr>
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Type.html">Type</a>&gt;</td><td class="name" onclick="toggle('dependentTemplateSpecializationType0')"><a name="dependentTemplateSpecializationType0Anchor">dependentTemplateSpecializationType</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1DependentTemplateSpecializationType.html">DependentTemplateSpecializationType</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="dependentTemplateSpecializationType0"><pre>Matches a dependent template specialization type.
+
+Example matches A<T>::template B<T>
+
+  template<typename T> struct A;
+  template<typename T> struct declToImport {
+    typename A<T>::template B<T> a;
+  };
+</pre></td></tr>
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Type.html">Type</a>&gt;</td><td class="name" onclick="toggle('deducedTemplateSpecializationType0')"><a name="deducedTemplateSpecializationType0Anchor">deducedTemplateSpecializationType</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1DeducedTemplateSpecializationType.html">DeducedTemplateSpecializationType</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="deducedTemplateSpecializationType0"><pre>Matches C++17 deduced template specialization types, e.g. deduced class
 template types.

clang/docs/ReleaseNotes.rst

@@ -1114,6 +1114,8 @@ AST Matchers
 
 - Add ``dependentNameType`` matcher to match a dependent name type.
 
+- Add ``dependentTemplateSpecializationType`` matcher to match a dependent template specialization type.
+
 clang-format
 ------------
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -7721,6 +7721,18 @@ AST_MATCHER_P(DecayedType, hasDecayedType, internal::Matcher<QualType>,
 /// \endcode
 extern const AstTypeMatcher<DependentNameType> dependentNameType;
 
+/// Matches a dependent template specialization type
+///
+/// Example matches A<T>::template B<T>
+/// \code
+///   template<typename T> struct A;
+///   template<typename T> struct declToImport {
+///     typename A<T>::template B<T> a;
+///   };
+/// \endcode
+extern const AstTypeMatcher<DependentTemplateSpecializationType>
+    dependentTemplateSpecializationType;
+
 /// Matches declarations whose declaration context, interpreted as a
 /// Decl, matches \c InnerMatcher.
 ///

clang/lib/ASTMatchers/ASTMatchersInternal.cpp

@@ -1109,6 +1109,8 @@ const AstTypeMatcher<TemplateTypeParmType> templateTypeParmType;
 const AstTypeMatcher<InjectedClassNameType> injectedClassNameType;
 const AstTypeMatcher<DecayedType> decayedType;
 const AstTypeMatcher<DependentNameType> dependentNameType;
+const AstTypeMatcher<DependentTemplateSpecializationType>
+    dependentTemplateSpecializationType;
 AST_TYPELOC_TRAVERSE_MATCHER_DEF(hasElementType,
                                  AST_POLYMORPHIC_SUPPORTED_TYPES(ArrayType,
                                                                  ComplexType));

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -224,6 +224,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(declRefExpr);
   REGISTER_MATCHER(dependentNameType);
   REGISTER_MATCHER(dependentScopeDeclRefExpr);
+  REGISTER_MATCHER(dependentTemplateSpecializationType);
   REGISTER_MATCHER(declStmt);
   REGISTER_MATCHER(declaratorDecl);
   REGISTER_MATCHER(decltypeType);

clang/unittests/AST/ASTImporterTest.cpp

@@ -763,10 +763,6 @@ TEST_P(ImportType, ImportPackExpansion) {
                                    implicitCastExpr(has(declRefExpr()))))))));
 }
 
-const internal::VariadicDynCastAllOfMatcher<Type,
-                                            DependentTemplateSpecializationType>
-    dependentTemplateSpecializationType;
-
 TEST_P(ImportType, ImportDependentTemplateSpecialization) {
   MatchVerifier<Decl> Verifier;
   testImport("template<typename T>"

clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp

@@ -1926,6 +1926,21 @@ TEST_P(ASTMatchersTest, DependentNameType) {
       dependentNameType()));
 }
 
+TEST_P(ASTMatchersTest, DependentTemplateSpecializationType) {
+  if (!GetParam().isCXX()) {
+    return;
+  }
+
+  EXPECT_TRUE(matches(
+      R"(
+        template<typename T> struct A;
+        template<typename T> struct declToImport {
+          typename A<T>::template B<T> a;
+        };
+      )",
+      dependentTemplateSpecializationType()));
+}
+
 TEST_P(ASTMatchersTest, RecordType) {
   EXPECT_TRUE(matches("struct S {}; struct S s;",
                       recordType(hasDeclaration(recordDecl(hasName("S"))))));