[clangd] Added highlighting to enum constants.

[jvikstrom]

Summary

VSCode does not have a scope for enum constants. So they were placed under "constant.other.enum" as that seems to be the most correct scope for enum constants. However, this makes theia color them blue (the same color it uses for keywords).

[hokein]

mostly good.

clang-tools-extra/clangd/SemanticHighlighting.cpp

122

nit: clang-format.

257

could you check the tm scope on vscode? They seem to use variable.other.enummember.

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

106–107

since we have a dedicated testcase for enum, could you extend the testcase here?

[jvikstrom]

Address comments.

[hokein]

clang-tools-extra/clangd/SemanticHighlighting.cpp

257

this comment is undone, vscode is using https://github.com/microsoft/vscode/blob/master/extensions/cpp/syntaxes/cpp.tmLanguage.json#L10024

[jvikstrom]

clang-tools-extra/clangd/SemanticHighlighting.cpp

257

Oh yeah, I was going to write a comment about keeping it as constant.other.enum or something similar to it. Because it's not really a variable. But as we've stuck to the same TM scopes as vscode we should probably keep doing that so I'll change to variable.other.enummember and land.

clang-tools-extra/clangd/SemanticHighlighting.h

 namespace clang {
 namespace clangd {
 
 enum class HighlightingKind {
   Variable = 0,
   Function,
   Class,
   Enum,
+  EnumConstant,
   Namespace,
 
   NumKinds,
 };
 
 // Contains all information needed for the highlighting a token.
 struct HighlightingToken {
   HighlightingKind Kind;

clang-tools-extra/clangd/SemanticHighlighting.cpp

void addToken(SourceLocation Loc, const NamedDecl *D) {
     if (isa<CXXConstructorDecl>(D)) {
       addToken(Loc, HighlightingKind::Class);
       return;
     }
     if (isa<EnumDecl>(D)) {
       addToken(Loc, HighlightingKind::Enum);
       return;
     }
+    if (isa<EnumConstantDecl>(D)) {
+      addToken(Loc, HighlightingKind::EnumConstant);
+      return;
+    }
     if (isa<VarDecl>(D)) {
       addToken(Loc, HighlightingKind::Variable);
       return;
     }
     if (isa<FunctionDecl>(D)) {
       addToken(Loc, HighlightingKind::Function);
       return;
     }
llvm::StringRef toTextMateScope(HighlightingKind Kind) {
   case HighlightingKind::Function:
     return "entity.name.function.cpp";
   case HighlightingKind::Variable:
     return "variable.cpp";
   case HighlightingKind::Class:
     return "entity.name.type.class.cpp";
   case HighlightingKind::Enum:
     return "entity.name.type.enum.cpp";
+  case HighlightingKind::EnumConstant:
+    return "constant.other.enum.cpp";
   case HighlightingKind::Namespace:
     return "entity.name.namespace.cpp";
   case HighlightingKind::NumKinds:
     llvm_unreachable("must not pass NumKinds to the function");
   }
   llvm_unreachable("unhandled HighlightingKind");
 }
 
 } // namespace clangd
 } // namespace clang

clang-tools-extra/clangd/test/semantic-highlighting.test

 # CHECK-NEXT:          ],
 # CHECK-NEXT:          [
 # CHECK-NEXT:            "entity.name.type.class.cpp"
 # CHECK-NEXT:          ],
 # CHECK-NEXT:          [
 # CHECK-NEXT:            "entity.name.type.enum.cpp"
 # CHECK-NEXT:          ],
 # CHECK-NEXT:          [
+# CHECK-NEXT:            "constant.other.enum.cpp"
+# CHECK-NEXT:          ],
+# CHECK-NEXT:          [
 # CHECK-NEXT:            "entity.name.namespace.cpp"
 # CHECK-NEXT:          ]
 # CHECK-NEXT:        ]
 # CHECK-NEXT:      },
 ---
 {"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"test:///foo.cpp","languageId":"cpp","version":1,"text":"int x = 2;"}}}
 #      CHECK:  "method": "textDocument/semanticHighlighting",
 # CHECK-NEXT:  "params": {

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

 void checkHighlightings(llvm::StringRef Code) {
   Annotations Test(Code);
   auto AST = TestTU::withCode(Test.code()).build();
   static const std::map<HighlightingKind, std::string> KindToString{
       {HighlightingKind::Variable, "Variable"},
       {HighlightingKind::Function, "Function"},
       {HighlightingKind::Class, "Class"},
       {HighlightingKind::Enum, "Enum"},
-      {HighlightingKind::Namespace, "Namespace"}};
+      {HighlightingKind::Namespace, "Namespace"},
+      {HighlightingKind::EnumConstant, "EnumConstant"}};
   std::vector<HighlightingToken> ExpectedTokens;
   for (const auto &KindString : KindToString) {
     std::vector<HighlightingToken> Toks = makeHighlightingTokens(
         Test.ranges(KindString.second), KindString.first);
     ExpectedTokens.insert(ExpectedTokens.end(), Toks.begin(), Toks.end());
   }
 
   auto ActualTokens = getSemanticHighlightings(AST);
R"cpp(
       $Class[[B]]::$Class[[B]]() {}
       $Class[[B]]::~$Class[[B]]() {}
       void $Function[[f]] () {
         $Class[[B]] $Variable[[BB]] = $Class[[B]]();
         $Variable[[BB]].~$Class[[B]]();
         $Class[[B]]();
       }
     )cpp",
     R"cpp(
-      enum class $Enum[[E]] {};
-      enum $Enum[[EE]] {};
+      enum class $Enum[[E]] {
+        $EnumConstant[[A]],
+        $EnumConstant[[B]],
+      };
+      enum $Enum[[EE]] {
+        $EnumConstant[[Hi]],
+      };
       struct $Class[[A]] {
         $Enum[[E]] EEE;
         $Enum[[EE]] EEEE;
       };
+      int $Variable[[I]] = $EnumConstant[[Hi]];
+      $Enum[[E]] $Variable[[L]] = $Enum[[E]]::$EnumConstant[[B]];
     )cpp",
     R"cpp(
       namespace $Namespace[[abc]] {
         namespace {}
         namespace $Namespace[[bcd]] {
           struct $Class[[A]] {};
           namespace $Namespace[[cde]] {
             struct $Class[[A]] {
               enum class $Enum[[B]] {
-                Hi,
+                $EnumConstant[[Hi]],
               };
             };
           }
         }
       }
       using namespace $Namespace[[abc]]::$Namespace[[bcd]];
       namespace $Namespace[[vwz]] =
             $Namespace[[abc]]::$Namespace[[bcd]]::$Namespace[[cde]];
       $Namespace[[abc]]::$Namespace[[bcd]]::$Class[[A]] $Variable[[AA]];
       $Namespace[[vwz]]::$Class[[A]]::$Enum[[B]] $Variable[[AAA]] =
-            $Namespace[[vwz]]::$Class[[A]]::$Enum[[B]]::Hi;
+            $Namespace[[vwz]]::$Class[[A]]::$Enum[[B]]::$EnumConstant[[Hi]];
       ::$Namespace[[vwz]]::$Class[[A]] $Variable[[B]];
       ::$Namespace[[abc]]::$Namespace[[bcd]]::$Class[[A]] $Variable[[BB]];
     )cpp"};
   for (const auto &TestCase : TestCases) {
     checkHighlightings(TestCase);
   }
 }