[Clang][ASTMatcher] Add a matcher for the name of a DependentScopeDec…

…lRefExpr (#121656)

Add the `hasDependentName` matcher to match the name of
`DependentScopeDeclRefExpr`

Fixes #121610

clang/docs/LibASTMatchersReference.html

@@ -3449,6 +3449,19 @@ <h2 id="narrowing-matchers">Narrowing Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1DependentScopeDeclRefExpr.html">DependentScopeDeclRefExpr</a>&gt;</td><td class="name" onclick="toggle('hasDependentName0')"><a name="hasDependentName0Anchor">hasDependentName</a></td><td>std::string N</td></tr>
+<tr><td colspan="4" class="doc" id="hasDependentName0"><pre>Matches the dependent name of a DependentScopeDeclRefExpr.
+
+Matches the dependent name of a DependentScopeDeclRefExpr
+
+Given:
+
+  template &lt;class T&lt; class X : T { void f() { T::v; } };
+
+dependentScopeDeclRefExpr(hasDependentName("v")) matches `T::v`
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXDependentScopeMemberExpr.html">CXXDependentScopeMemberExpr</a>&gt;</td><td class="name" onclick="toggle('memberHasSameNameAsBoundNode0')"><a name="memberHasSameNameAsBoundNode0Anchor">memberHasSameNameAsBoundNode</a></td><td>std::string BindingID</td></tr>
 <tr><td colspan="4" class="doc" id="memberHasSameNameAsBoundNode0"><pre>Matches template-dependent, but known, member names against an already-bound
 node

clang/docs/ReleaseNotes.rst

@@ -1116,6 +1116,8 @@ AST Matchers
 
 - Add ``dependentTemplateSpecializationType`` matcher to match a dependent template specialization type.
 
+- Add ``hasDependentName`` matcher to match the dependent name of a DependentScopeDeclRefExpr.
+
 clang-format
 ------------
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -3257,6 +3257,17 @@ AST_MATCHER_P(CXXDependentScopeMemberExpr, memberHasSameNameAsBoundNode,
       });
 }
 
+/// Matches the dependent name of a DependentScopeDeclRefExpr
+///
+/// Given:
+/// \code
+///  template <class T> class X : T { void f() { T::v; } };
+/// \endcode
+/// \c dependentScopeDeclRefExpr(hasDependentName("v")) matches `T::v`
+AST_MATCHER_P(DependentScopeDeclRefExpr, hasDependentName, std::string, N) {
+  return Node.getDeclName().getAsString() == N;
+}
+
 /// Matches C++ classes that are directly or indirectly derived from a class
 /// matching \c Base, or Objective-C classes that directly or indirectly
 /// subclass a class matching \c Base.

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -314,6 +314,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(hasDeducedType);
   REGISTER_MATCHER(hasDefaultArgument);
   REGISTER_MATCHER(hasDefinition);
+  REGISTER_MATCHER(hasDependentName);
   REGISTER_MATCHER(hasDescendant);
   REGISTER_MATCHER(hasDestinationType);
   REGISTER_MATCHER(hasDirectBase);

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

@@ -2235,6 +2235,24 @@ TEST_P(ASTMatchersTest, ArgumentCountIs_CXXConstructExpr) {
                  Constructor1Arg));
 }
 
+TEST_P(ASTMatchersTest, HasDependentName_DependentScopeDeclRefExpr) {
+  if (!GetParam().isCXX() || GetParam().hasDelayedTemplateParsing()) {
+    // FIXME: Fix this test to work with delayed template parsing.
+    return;
+  }
+
+  EXPECT_TRUE(matches("template <class T> class X : T { void f() { T::v; } };",
+                      dependentScopeDeclRefExpr(hasDependentName("v"))));
+
+  EXPECT_TRUE(matches("template <typename T> struct S { static T Foo; };"
+                      "template <typename T> void x() { (void)S<T>::Foo; }",
+                      dependentScopeDeclRefExpr(hasDependentName("Foo"))));
+
+  EXPECT_TRUE(matches("template <typename T> struct S { static T foo(); };"
+                      "template <typename T> void x() { S<T>::foo(); }",
+                      dependentScopeDeclRefExpr(hasDependentName("foo"))));
+}
+
 TEST(ASTMatchersTest, NamesMember_CXXDependentScopeMemberExpr) {
 
   // Member functions: