[ASTMatchers] add typeAliasTemplateDecl matcher.

[hokein]

You also need to add a new generated document (docs/LibASTMatchersReference.html) for that. Please run clang/docs/tools/dump_ast_matchers.py, it will do the stuff for you.

[ioeric]

• generate html for the new matcher.

[ioeric]

PTAL

[aaron.ballman]

include/clang/ASTMatchers/ASTMatchers.h

191

Be sure to add this to Registry.cpp so that it can be used as a dynamic matcher in clang-query.

[ioeric]

• Register the matcher to Dynamic.

[ioeric]

include/clang/ASTMatchers/ASTMatchers.h

191

Done. Thanks for the reminder!

[aaron.ballman]

LGTM!

include/clang/ASTMatchers/ASTMatchers.h

 /// \code
 ///   typedef int X;
 ///   using Y = int;
 /// \endcode
 /// typeAliasDecl()
 ///   matches "using Y = int", but not "typedef int X"
 const internal::VariadicDynCastAllOfMatcher<Decl, TypeAliasDecl> typeAliasDecl;
 
+/// \brief Matches type alias template declarations.
+///
+/// typeAliasTemplateDecl() matches
+/// \code
+///   template <typename T>
+///   using Y = X<T>;
+/// \endcode
+const internal::VariadicDynCastAllOfMatcher<Decl, TypeAliasTemplateDecl>
+    typeAliasTemplateDecl;
+
 /// \brief Matches AST nodes that were expanded within the main-file.
 ///
 /// Example matches X but not Y
 ///   (matcher = cxxRecordDecl(isExpansionInMainFile())
 /// \code
 ///   #include <Y.h>
 ///   class X {};
 /// \endcode

unittests/ASTMatchers/ASTMatchersNodeTest.cpp

 
 TEST(TypedefNameDeclMatcher, Match) {
   EXPECT_TRUE(matches("typedef int typedefNameDeclTest1;",
                       typedefNameDecl(hasName("typedefNameDeclTest1"))));
   EXPECT_TRUE(matches("using typedefNameDeclTest2 = int;",
                       typedefNameDecl(hasName("typedefNameDeclTest2"))));
 }
 
+TEST(TypeAliasTemplateDeclMatcher, Match) {
+  std::string Code = R"(
+    template <typename T>
+    class X { T t; };
+
+    template <typename T>
+    using typeAliasTemplateDecl = X<T>;
+
+    using typeAliasDecl = X<int>;
+  )";
+  EXPECT_TRUE(
+      matches(Code, typeAliasTemplateDecl(hasName("typeAliasTemplateDecl"))));
+  EXPECT_TRUE(
+      notMatches(Code, typeAliasTemplateDecl(hasName("typeAliasDecl"))));
+}
+
 TEST(ObjCMessageExprMatcher, SimpleExprs) {
   // don't find ObjCMessageExpr where none are present
   EXPECT_TRUE(notMatchesObjC("", objcMessageExpr(anything())));
 
   std::string Objc1String =
     "@interface Str "
       " - (Str *)uppercaseString:(Str *)str;"
       "@end "