[clangd] Don't rename on symbols from system headers.

Fixes clangd/clangd#963.

Differential Revision: https://reviews.llvm.org/D116643

Author: hokein

clang-tools-extra/clangd/refactor/Rename.cpp

@@ -159,13 +159,17 @@ llvm::DenseSet<const NamedDecl *> locateDeclAt(ParsedAST &AST,
   return Result;
 }
 
-// By default, we exclude C++ standard symbols and protobuf symbols as rename
-// these symbols would change system/generated files which are unlikely to be
-// modified.
+// By default, we exclude symbols from system headers and protobuf symbols as
+// renaming these symbols would change system/generated files which are unlikely
+// to be good candidates for modification.
 bool isExcluded(const NamedDecl &RenameDecl) {
-  if (isProtoFile(RenameDecl.getLocation(),
-                  RenameDecl.getASTContext().getSourceManager()))
+  const auto &SM = RenameDecl.getASTContext().getSourceManager();
+  if (SM.isInSystemHeader(RenameDecl.getLocation()))
     return true;
+  if (isProtoFile(RenameDecl.getLocation(), SM))
+    return true;
+  // FIXME: Remove this std symbol list, as they should be covered by the
+  // above isInSystemHeader check.
   static const auto *StdSymbols = new llvm::DenseSet<llvm::StringRef>({
 #define SYMBOL(Name, NameSpace, Header) {#NameSpace #Name},
 #include "StdSymbolMap.inc"

clang-tools-extra/clangd/unittests/RenameTests.cpp

@@ -1198,6 +1198,29 @@ TEST(RenameTest, MainFileReferencesOnly) {
             expectedResult(Code, NewName));
 }
 
+TEST(RenameTest, NoRenameOnSymbolsFromSystemHeaders) {
+  // filter out references not from main file.
+  llvm::StringRef Test =
+      R"cpp(
+        #include <system>
+        SystemSym^bol abc;
+        )cpp";
+
+  Annotations Code(Test);
+  auto TU = TestTU::withCode(Code.code());
+  TU.AdditionalFiles["system"] = R"cpp(
+    class SystemSymbol {};
+    )cpp";
+  TU.ExtraArgs = {"-isystem", testRoot()};
+  auto AST = TU.build();
+  llvm::StringRef NewName = "abcde";
+
+  auto Results = rename({Code.point(), NewName, AST, testPath(TU.Filename)});
+  EXPECT_FALSE(Results) << "expected rename returned an error: " << Code.code();
+  auto ActualMessage = llvm::toString(Results.takeError());
+  EXPECT_THAT(ActualMessage, testing::HasSubstr("not a supported kind"));
+}
+
 TEST(RenameTest, ProtobufSymbolIsExcluded) {
   Annotations Code("Prot^obuf buf;");
   auto TU = TestTU::withCode(Code.code());