[clang][tooling] Fix name range-selector to handle TypeLocs correctly.

Previously, where `name` was applied to a template-specialization TypeLoc, it
returned the entire specialization (name, brackets, args) rather than just the
name identifier. With this change, exactly the name token is selected.

Differential Revision: https://reviews.llvm.org/D158771

Author: ymand

clang/lib/Tooling/Transformer/RangeSelector.cpp

@@ -232,9 +232,11 @@ RangeSelector transformer::name(std::string ID) {
     if (const auto *T = Node.get<TypeLoc>()) {
       TypeLoc Loc = *T;
       auto ET = Loc.getAs<ElaboratedTypeLoc>();
-      if (!ET.isNull()) {
+      if (!ET.isNull())
         Loc = ET.getNamedTypeLoc();
-      }
+      if (auto SpecLoc = Loc.getAs<TemplateSpecializationTypeLoc>();
+          !SpecLoc.isNull())
+        return CharSourceRange::getTokenRange(SpecLoc.getTemplateNameLoc());
       return CharSourceRange::getTokenRange(Loc.getSourceRange());
     }
     return typeError(ID, Node.getNodeKind(),

clang/unittests/Tooling/RangeSelectorTest.cpp

@@ -486,6 +486,22 @@ TEST(RangeSelectorTest, NameOpTypeLoc) {
   EXPECT_THAT_EXPECTED(select(name(CtorTy), MatchC), HasValue("Foo"));
 }
 
+TEST(RangeSelectorTest, NameOpTemplateSpecializationTypeLoc) {
+  StringRef Code = R"cc(
+    namespace ns {
+    template <typename T>
+    struct Foo {};
+    }  // namespace ns
+
+    ns::Foo<int> a;
+  )cc";
+  const char *Loc = "tyloc";
+  // Matches declaration of `a`.
+  TestMatch MatchA =
+      matchCode(Code, varDecl(hasName("a"), hasTypeLoc(typeLoc().bind(Loc))));
+  EXPECT_THAT_EXPECTED(select(name(Loc), MatchA), HasValue("Foo"));
+}
+
 TEST(RangeSelectorTest, NameOpErrors) {
   EXPECT_THAT_EXPECTED(selectFromTrivial(name("unbound_id")),
                        Failed<StringError>(withUnboundNodeMessage()));