Handle variable templates in isInstantiated and isInTemplateInstantiation matchers

Fix `isInstantiated`  and `isInTemplateInstantiation` matchers,
so they return true for instantitions of the variable template,
and any declaration in statement contained in such instantiation.

Author: tomasz-kaminski-sonarsource

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)));
 }
 
@@ -6771,7 +6772,8 @@ AST_MATCHER_FUNCTION(internal::Matcher<Decl>, isInstantiated) {
 AST_MATCHER_FUNCTION(internal::Matcher<Stmt>, isInTemplateInstantiation) {
   return stmt(
       hasAncestor(decl(anyOf(cxxRecordDecl(isTemplateInstantiation()),
-                             functionDecl(isTemplateInstantiation())))));
+                             functionDecl(isTemplateInstantiation()),
+                             varDecl(isTemplateInstantiation())))));
 }
 
 /// Matches explicit template specializations of function, class, or

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

@@ -3313,6 +3313,47 @@ 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;