[clang-tools-extra] ddfe13e - [clangd] Produce semantic token for name referring to UnresolvedUsingValueDecl

[Nathan Ridge via cfe-commits]

Author: Nathan Ridge
Date: 2021-04-25T16:43:58-04:00
New Revision: ddfe13e757cb72c056cba8d889d6cb8ee69f1afa

URL: https://github.com/llvm/llvm-project/commit/ddfe13e757cb72c056cba8d889d6cb8ee69f1afa
DIFF: https://github.com/llvm/llvm-project/commit/ddfe13e757cb72c056cba8d889d6cb8ee69f1afa.diff

LOG: [clangd] Produce semantic token for name referring to UnresolvedUsingValueDecl

For now, use the token kind Unknown. We may be able to improve on this
using HeuristicResolver.

Differential Revision: https://reviews.llvm.org/D99052

Added: 
    

Modified: 
    clang-tools-extra/clangd/SemanticHighlighting.cpp
    clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp

Removed: 
    


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diff  --git a/clang-tools-extra/clangd/SemanticHighlighting.cpp b/clang-tools-extra/clangd/SemanticHighlighting.cpp
index cf06eac01a34..c4cb57e3f32b 100644
--- a/clang-tools-extra/clangd/SemanticHighlighting.cpp
+++ b/clang-tools-extra/clangd/SemanticHighlighting.cpp
@@ -133,6 +133,10 @@ llvm::Optional<HighlightingKind> kindForDecl(const NamedDecl *D) {
     return HighlightingKind::TemplateParameter;
   if (isa<ConceptDecl>(D))
     return HighlightingKind::Concept;
+  if (isa<UnresolvedUsingValueDecl>(D)) {
+    // FIXME: We may be able to do better using HeuristicResolver.
+    return HighlightingKind::Unknown;
+  }
   return llvm::None;
 }
 llvm::Optional<HighlightingKind> kindForType(const Type *TP) {
@@ -228,6 +232,12 @@ bool isAbstract(const Decl *D) {
   return false;
 }
 
+bool isDependent(const Decl *D) {
+  if (isa<UnresolvedUsingValueDecl>(D))
+    return true;
+  return false;
+}
+
 // For a macro usage `DUMP(foo)`, we want:
 //  - DUMP --> "macro"
 //  - foo --> "variable".
@@ -619,9 +629,14 @@ std::vector<HighlightingToken> getSemanticHighlightings(ParsedAST &AST) {
             Tok.addModifier(HighlightingModifier::Static);
           if (isAbstract(Decl))
             Tok.addModifier(HighlightingModifier::Abstract);
+          if (isDependent(Decl))
+            Tok.addModifier(HighlightingModifier::DependentName);
           if (Decl->isDeprecated())
             Tok.addModifier(HighlightingModifier::Deprecated);
-          if (R.IsDecl)
+          // Do not treat an UnresolvedUsingValueDecl as a declaration.
+          // It's more common to think of it as a reference to the
+          // underlying declaration.
+          if (R.IsDecl && !isa<UnresolvedUsingValueDecl>(Decl))
             Tok.addModifier(HighlightingModifier::Declaration);
         }
       },

diff  --git a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
index d8dc3b061df5..7e979ee4e75d 100644
--- a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
@@ -688,6 +688,20 @@ sizeof...($TemplateParameter[[Elements]]);
         @implementation $Class[[Foo]]($Namespace_decl[[Bar]])
         @end
       )cpp",
+      // Member imported from dependent base
+      R"cpp(
+        template <typename> struct $Class_decl[[Base]] {
+          int $Field_decl[[member]];
+        };
+        template <typename $TemplateParameter_decl[[T]]>
+        struct $Class_decl[[Derived]] : $Class[[Base]]<$TemplateParameter[[T]]> {
+          using $Class[[Base]]<$TemplateParameter[[T]]>::$Unknown_dependentName[[member]];
+
+          void $Method_decl[[method]]() {
+            (void)$Unknown_dependentName[[member]];
+          }
+        };
+      )cpp",
   };
   for (const auto &TestCase : TestCases)
     // Mask off scope modifiers to keep the tests manageable.