[clang-tools-extra] 7138e75 - [clangd] Avoid recursion on UnresolvedUsingValueDecl during semantic highlighting

[Nathan Ridge via cfe-commits]

Author: Nathan Ridge
Date: 2023-03-19T04:30:33-04:00
New Revision: 7138e75d1bb5008b9278359dc83f05c668e104c2

URL: https://github.com/llvm/llvm-project/commit/7138e75d1bb5008b9278359dc83f05c668e104c2
DIFF: https://github.com/llvm/llvm-project/commit/7138e75d1bb5008b9278359dc83f05c668e104c2.diff

LOG: [clangd] Avoid recursion on UnresolvedUsingValueDecl during semantic highlighting

Fixes https://github.com/clangd/clangd/issues/1313

Differential Revision: https://reviews.llvm.org/D134827

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 19f79f793420d..2122cb86c2834 100644
--- a/clang-tools-extra/clangd/SemanticHighlighting.cpp
+++ b/clang-tools-extra/clangd/SemanticHighlighting.cpp
@@ -156,7 +156,7 @@ std::optional<HighlightingKind> kindForDecl(const NamedDecl *D,
     return HighlightingKind::Concept;
   if (const auto *UUVD = dyn_cast<UnresolvedUsingValueDecl>(D)) {
     auto Targets = Resolver->resolveUsingValueDecl(UUVD);
-    if (!Targets.empty()) {
+    if (!Targets.empty() && Targets[0] != UUVD) {
       return kindForDecl(Targets[0], Resolver);
     }
     return HighlightingKind::Unknown;

diff  --git a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
index cba318df3d2fe..9a3ab30eafabb 100644
--- a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
@@ -1045,7 +1045,15 @@ sizeof...($TemplateParameter[[Elements]]);
           auto $LocalVariable_def[[s]] = $Operator[[new]] $Class[[Foo]]$Bracket[[<]]$TemplateParameter[[T]]$Bracket[[>]]();
           $Operator[[delete]] $LocalVariable[[s]];
         }
-      )cpp"};
+      )cpp",
+      // Recursive UsingValueDecl
+      R"cpp(
+        template <int> class $Class_def[[X]] {
+          template <int> class $Class_def[[Y]] {
+            using $Class[[Y]]<0>::$Unknown_dependentName[[xxx]];
+          };
+        };
+    )cpp"};
   for (const auto &TestCase : TestCases)
     // Mask off scope modifiers to keep the tests manageable.
     // They're tested separately.