[Clang][ASTMatcher] Add dependentScopeDeclRefExpr Matcher

[AmrDeveloper]

Add AST Matcher for DependentScopeDeclRefExpr

Fixes: #120937

[llvmbot]

@llvm/pr-subscribers-clang

Author: Amr Hesham (AmrDeveloper)

Changes

Add AST Matcher for DependentScopeDeclRefExpr

Fixes: #120937

---

Full diff: https://github.com/llvm/llvm-project/pull/120996.diff

7 Files Affected:

• (modified) clang/docs/LibASTMatchersReference.html (+6)
• (modified) clang/docs/ReleaseNotes.rst (+2)
• (modified) clang/include/clang/ASTMatchers/ASTMatchers.h (+9)
• (modified) clang/lib/ASTMatchers/ASTMatchersInternal.cpp (+1)
• (modified) clang/lib/ASTMatchers/Dynamic/Registry.cpp (+1)
• (modified) clang/unittests/AST/ASTImporterTest.cpp (-3)
• (modified) clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp (+18-3)

diff --git a/clang/docs/LibASTMatchersReference.html b/clang/docs/LibASTMatchersReference.html
index f18e9cf1341696..ddc99020604c94 100644
--- a/clang/docs/LibASTMatchersReference.html
+++ b/clang/docs/LibASTMatchersReference.html
@@ -1842,6 +1842,12 @@ <h2 id="decl-matchers">Node Matchers</h2>
   if (x) {}
 </pre></td></tr>
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('dependentScopeDeclRefExpr0')"><a name="dependentScopeDeclRefExpr0Anchor">dependentScopeDeclRefExpr</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1DependentScopeDeclRefExpr.html">DependentScopeDeclRefExpr</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="dependentScopeDeclRefExpr0"><pre>Matches expressions that refer to dependent scope declarations.
+
+Example matches T::v
+   template <class T> class X : T { void f() { T::v; } };
+</pre></td></tr>
 
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('declStmt0')"><a name="declStmt0Anchor">declStmt</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1DeclStmt.html">DeclStmt</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="declStmt0"><pre>Matches declaration statements.
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8b984ecaefecaf..2a84a4704f0c21 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1101,6 +1101,8 @@ AST Matchers
 
 - Ensure ``pointee`` matches Objective-C pointer types.
 
+- Add ``dependentScopeDeclRefExpr`` matcher to match expressions that refer to dependent scope declarations.
+
 clang-format
 ------------
 
diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
index 897aa25dc95cc1..fd8d9c99eca163 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -2125,6 +2125,15 @@ extern const internal::VariadicDynCastAllOfMatcher<Stmt, Expr> expr;
 extern const internal::VariadicDynCastAllOfMatcher<Stmt, DeclRefExpr>
     declRefExpr;
 
+/// Matches expressions that refer to dependent scope declarations.
+///
+/// example matches T::v;
+/// \code
+///  template <class T> class X : T { void f() { T::v; } };
+/// \endcode
+extern const internal::VariadicDynCastAllOfMatcher<Stmt, DependentScopeDeclRefExpr>
+    dependentScopeDeclRefExpr;
+
 /// Matches a reference to an ObjCIvar.
 ///
 /// Example: matches "a" in "init" method:
diff --git a/clang/lib/ASTMatchers/ASTMatchersInternal.cpp b/clang/lib/ASTMatchers/ASTMatchersInternal.cpp
index bf9dc5f2373f9e..ebe30f97b08268 100644
--- a/clang/lib/ASTMatchers/ASTMatchersInternal.cpp
+++ b/clang/lib/ASTMatchers/ASTMatchersInternal.cpp
@@ -924,6 +924,7 @@ const internal::VariadicDynCastAllOfMatcher<Stmt, CXXRewrittenBinaryOperator>
 const internal::VariadicDynCastAllOfMatcher<Stmt, CXXFoldExpr> cxxFoldExpr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, Expr> expr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, DeclRefExpr> declRefExpr;
+const internal::VariadicDynCastAllOfMatcher<Stmt, DependentScopeDeclRefExpr> dependentScopeDeclRefExpr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, ObjCIvarRefExpr> objcIvarRefExpr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, BlockExpr> blockExpr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, IfStmt> ifStmt;
diff --git a/clang/lib/ASTMatchers/Dynamic/Registry.cpp b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
index 837633fb2f0601..685d626d2978bf 100644
--- a/clang/lib/ASTMatchers/Dynamic/Registry.cpp
+++ b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
@@ -222,6 +222,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(decompositionDecl);
   REGISTER_MATCHER(declCountIs);
   REGISTER_MATCHER(declRefExpr);
+  REGISTER_MATCHER(dependentScopeDeclRefExpr);
   REGISTER_MATCHER(declStmt);
   REGISTER_MATCHER(declaratorDecl);
   REGISTER_MATCHER(decltypeType);
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index f3f314b723dfc6..ec062a5cc953b8 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3172,9 +3172,6 @@ TEST_P(ImportDecl, ImportFieldOrder) {
              recordDecl(hasFieldOrder({"b", "a"})));
 }
 
-const internal::VariadicDynCastAllOfMatcher<Expr, DependentScopeDeclRefExpr>
-    dependentScopeDeclRefExpr;
-
 TEST_P(ImportExpr, DependentScopeDeclRefExpr) {
   MatchVerifier<Decl> Verifier;
   testImport("template <typename T> struct S { static T foo; };"
diff --git a/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp
index 9bc287e07224aa..0663cc35d7a52a 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp
@@ -556,6 +556,22 @@ TEST_P(ASTMatchersTest, DeclRefExpr) {
                          Reference));
 }
 
+TEST_P(ASTMatchersTest, DependentScopeDeclRefExpr) {
+  if (!GetParam().isCXX()) {
+    // FIXME: Add a test for `dependentScopeDeclRefExpr()` that does not depend on C++.
+    return;
+  }
+
+  EXPECT_TRUE(
+      matches("template <class T> class X : T { void f() { T::v; } };",
+                 dependentScopeDeclRefExpr()));
+
+  EXPECT_TRUE(
+      matches("template <typename T> struct S { static T Foo; };"
+                    "template <typename T> void declToImport() { (void)S<T>::Foo; }",
+                 dependentScopeDeclRefExpr()));
+}
+
 TEST_P(ASTMatchersTest, CXXMemberCallExpr) {
   if (!GetParam().isCXX()) {
     return;
@@ -629,10 +645,9 @@ TEST_P(ASTMatchersTest, MemberExpr_MatchesVariable) {
   EXPECT_TRUE(matches("template <class T>"
                       "class X : T { void f() { this->T::v; } };",
                       cxxDependentScopeMemberExpr()));
-  // FIXME: Add a matcher for DependentScopeDeclRefExpr.
   EXPECT_TRUE(
-      notMatches("template <class T> class X : T { void f() { T::v; } };",
-                 cxxDependentScopeMemberExpr()));
+      matches("template <class T> class X : T { void f() { T::v; } };",
+                 dependentScopeDeclRefExpr()));
   EXPECT_TRUE(matches("template <class T> void x() { T t; t.v; }",
                       cxxDependentScopeMemberExpr()));
 }

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[HighCommander4]

Thanks, this looks pretty good!

[HighCommander4]

The concept of template-dependence (and thus DependentScopeDeclRefExpr nodes) only exist in C++, so it's expected that the test depends on C++.

Based on some other tests that check this condition, please revise the comment to instead say:

// FIXME: Fix this test to work with delayed template parsing.

[AmrDeveloper]

Thank you, I updated it :D

[HighCommander4]

Thanks, LGTM!

I will wait a few days before merging in case anyone else has feedback.

[HighCommander4]

Went ahead and merged this. Thanks @AmrDeveloper!

[HighCommander4]

By the way, in case you're interested in doing another one, I filed #121240 about another missing matcher I came across.

[AmrDeveloper]

By the way, in case you're interested in doing another one, I filed #121240 about another missing matcher I came across.

Sure, I am interested, Thank you :D