[clangd] Add scoped enum constants to all-scopes-completion

[tom-anders]

Summary

This was originally part of https://reviews.llvm.org/D136925, but we decided to move it to a separate patch.
In case it turns out to be controversial, it can be reverted more easily.

[tom-anders]

Added missing hunk in CodeComplete.cpp

[tom-anders]

Rebase onto previous commit

[nridge]

The test added in the previous patch, CompletionTest.Enums, needs to be updated to reflect this change (Scoped::Clangd3 now appears as a completion).

clang-tools-extra/clangd/CodeComplete.cpp

2149

Why remove the (InTopLevelScope(*EnumDecl) || InClassScope(*EnumDecl)) part?

[tom-anders]

Update CompletionTest.Enums, keep scope condition in isIndexedForCodeCompletion

[tom-anders]

clang-tools-extra/clangd/CodeComplete.cpp

2149

Huh, because I thought this covered all the scopes where you could declare enums anyway, but of course that's wrong - You can e.g. declare a function-local enum, which we of course don't want to index.

2149

d

[tom-anders]

Actually fix test...

[nridge]

Looks good, thanks

clang-tools-extra/clangd/CodeComplete.h

 SignatureHelp signatureHelp(PathRef FileName, Position Pos,
                             const PreambleData &Preamble,
                             const ParseInputs &ParseInput,
                             MarkupKind DocumentationFormat);
 
 // For index-based completion, we only consider:
 //   * symbols in namespaces or translation unit scopes (e.g. no class
 //     members, no locals)
-//   * enum constants in unscoped enum decl (e.g. "red" in "enum {red};")
+//   * enum constants (both scoped and unscoped)
 //   * primary templates (no specializations)
 // For the other cases, we let Clang do the completion because it does not
 // need any non-local information and it will be much better at following
 // lookup rules. Other symbols still appear in the index for other purposes,
 // like workspace/symbols or textDocument/definition, but are not used for code
 // completion.
 bool isIndexedForCodeCompletion(const NamedDecl &ND, ASTContext &ASTCtx);
 

clang-tools-extra/clangd/CodeComplete.cpp

bool isIndexedForCodeCompletion(const NamedDecl &ND, ASTContext &ASTCtx) {
 
   if (InTopLevelScope(ND))
     return true;
 
   // Always index enum constants, even if they're not in the top level scope:
   // when
   // --all-scopes-completion is set, we'll want to complete those as well.
   if (const auto *EnumDecl = dyn_cast<clang::EnumDecl>(ND.getDeclContext()))
-    return (InTopLevelScope(*EnumDecl) || InClassScope(*EnumDecl)) && !EnumDecl->isScoped();
+    return (InTopLevelScope(*EnumDecl) || InClassScope(*EnumDecl));
 
   return false;
 }
 
 CompletionItem CodeCompletion::render(const CodeCompleteOptions &Opts) const {
   CompletionItem LSP;
   const auto *InsertInclude = Includes.empty() ? nullptr : &Includes[0];
   LSP.label = ((InsertInclude && InsertInclude->Insertion)
                    ? Opts.IncludeIndicator.Insert

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

const char *Source(R"cpp(
     void bar() {
       Clangd^
     })cpp");
   auto Index = TestTU::withHeaderCode(Header).index();
   clangd::CodeCompleteOptions Opts;
   Opts.Index = Index.get();
   Opts.AllScopes = true;
   auto R = completions(Source, {}, Opts);
-  EXPECT_THAT(R.Completions,
-              ElementsAre(AllOf(scope("ns::"), named("Clangd1"),
+  EXPECT_THAT(R.Completions, UnorderedElementsAre(
+                                 AllOf(scope("ns::"), named("Clangd1"),
                                        kind(CompletionItemKind::EnumMember)),
                                  AllOf(scope("ns::C::"), named("Clangd2"),
+                                       kind(CompletionItemKind::EnumMember)),
+                                 AllOf(scope("ns::Scoped::"), named("Clangd3"),
                                        kind(CompletionItemKind::EnumMember))));
 }
 
 TEST(CompletionTest, ScopeIsUnresolved) {
   clangd::CodeCompleteOptions Opts = {};
   Opts.AllScopes = true;
 
   auto Results = completions(R"cpp(
     namespace a {

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

TEST_F(SymbolCollectorTest, IncludeEnums) {
   )";
   runSymbolCollector(Header, /*Main=*/"");
   EXPECT_THAT(Symbols,
               UnorderedElementsAre(
                   AllOf(qName("Red"), forCodeCompletion(true)),
                   AllOf(qName("Color"), forCodeCompletion(true)),
                   AllOf(qName("Green"), forCodeCompletion(true)),
                   AllOf(qName("Color2"), forCodeCompletion(true)),
-                  AllOf(qName("Color2::Yellow"), forCodeCompletion(false)),
+                  AllOf(qName("Color2::Yellow"), forCodeCompletion(true)),
                   AllOf(qName("ns"), forCodeCompletion(true)),
                   AllOf(qName("ns::Black"), forCodeCompletion(true)),
                   AllOf(qName("Color3"), forCodeCompletion(true)),
                   AllOf(qName("Color3::Blue"), forCodeCompletion(true))));
 }
 
 TEST_F(SymbolCollectorTest, NamelessSymbols) {
   const std::string Header = R"(