[clang] 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] 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;