[clang] [clang][ASTMatcher] Handle variable templates in `isInstantiated` and `isInTemplateInstantiation` matchers (PR #110666)

[Fred Tingaud via cfe-commits]

https://github.com/frederic-tingaud-sonarsource updated https://github.com/llvm/llvm-project/pull/110666

>From be911d8d0a00d5c6d42b23b40ca6d6abec51966c Mon Sep 17 00:00:00 2001
From: Fred Tingaud <frederic.tingaud at sonarsource.com>
Date: Tue, 1 Oct 2024 16:10:55 +0200
Subject: [PATCH 1/2] Handle variable templates in isInstantiated and
 isInTemplateInstantiation matchers

Fix isInstantiated and isInTemplateInstantiation matchers, so they return true for instantiations of variable templates, and any declaration in statements contained in such instantiations.
---
 clang/include/clang/ASTMatchers/ASTMatchers.h |  9 +++--
 .../ASTMatchers/ASTMatchersNarrowingTest.cpp  | 39 +++++++++++++++++++
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
index f1c72efc238784..1b8757f422aa48 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -6750,7 +6750,8 @@ AST_POLYMORPHIC_MATCHER(isTemplateInstantiation,
 ///   matches 'A(int) {...};' and 'A(unsigned) {...}'.
 AST_MATCHER_FUNCTION(internal::Matcher<Decl>, isInstantiated) {
   auto IsInstantiation = decl(anyOf(cxxRecordDecl(isTemplateInstantiation()),
-                                    functionDecl(isTemplateInstantiation())));
+                                    functionDecl(isTemplateInstantiation()),
+                                    varDecl(isTemplateInstantiation())));
   return decl(anyOf(IsInstantiation, hasAncestor(IsInstantiation)));
 }
 
@@ -6769,9 +6770,9 @@ AST_MATCHER_FUNCTION(internal::Matcher<Decl>, isInstantiated) {
 ///   will NOT match j += 42; as it's shared between the template definition and
 ///   instantiation.
 AST_MATCHER_FUNCTION(internal::Matcher<Stmt>, isInTemplateInstantiation) {
-  return stmt(
-      hasAncestor(decl(anyOf(cxxRecordDecl(isTemplateInstantiation()),
-                             functionDecl(isTemplateInstantiation())))));
+  return stmt(hasAncestor(decl(anyOf(cxxRecordDecl(isTemplateInstantiation()),
+                                     functionDecl(isTemplateInstantiation()),
+                                     varDecl(isTemplateInstantiation())))));
 }
 
 /// Matches explicit template specializations of function, class, or
diff --git a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
index 611e1f9ba5327c..65904a1891b6ee 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -3313,6 +3313,45 @@ TEST_P(ASTMatchersTest,
                          declStmt(isInTemplateInstantiation())));
 }
 
+TEST_P(ASTMatchersTest, IsInstantiated_MatchesVariableInstantiation) {
+  if (!GetParam().isCXX14OrLater()) {
+    return;
+  }
+
+  EXPECT_TRUE(matches("template<typename T> int V = 10; void x() { V<int>; }",
+                      varDecl(isInstantiated())));
+}
+
+TEST_P(ASTMatchersTest, IsInstantiated_NotMatchesVariableDefinition) {
+  if (!GetParam().isCXX14OrLater()) {
+    return;
+  }
+
+  EXPECT_TRUE(notMatches("template<typename T> int V = 10;",
+                         varDecl(isInstantiated())));
+}
+
+TEST_P(ASTMatchersTest,
+       IsInTemplateInstantiation_MatchesVariableInstantiationStmt) {
+  if (!GetParam().isCXX14OrLater()) {
+    return;
+  }
+
+  EXPECT_TRUE(matches(
+      "template<typename T> auto V = []() { T i; }; void x() { V<int>(); }",
+      declStmt(isInTemplateInstantiation())));
+}
+
+TEST_P(ASTMatchersTest,
+       IsInTemplateInstantiation_NotMatchesVariableDefinitionStmt) {
+  if (!GetParam().isCXX14OrLater()) {
+    return;
+  }
+
+  EXPECT_TRUE(notMatches("template<typename T> auto V = []() { T i; };",
+                         declStmt(isInTemplateInstantiation())));
+}
+
 TEST_P(ASTMatchersTest, IsInTemplateInstantiation_Sharing) {
   if (!GetParam().isCXX()) {
     return;

>From 919389d82779a699cddb311d392a5e2f514eb7ce Mon Sep 17 00:00:00 2001
From: Fred Tingaud <frederic.tingaud at sonarsource.com>
Date: Mon, 7 Oct 2024 18:01:23 +0200
Subject: [PATCH 2/2] Add entry in Release Notes

---
 clang/docs/ReleaseNotes.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index a55a3b8687e46e..67f811b7ba5034 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -587,6 +587,8 @@ AST Matchers
 
 - Fixed a crash when traverse lambda expr with invalid captures. (#GH106444)
 
+- Fixed `isInstantiated` and `isInTemplateInstantiation` to also match for variable templates. (#GH110666)
+
 clang-format
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