diff --git a/clang-tools-extra/clangd/SemanticHighlighting.cpp b/clang-tools-extra/clangd/SemanticHighlighting.cpp
--- a/clang-tools-extra/clangd/SemanticHighlighting.cpp
+++ b/clang-tools-extra/clangd/SemanticHighlighting.cpp
@@ -468,7 +468,7 @@
   const LangOptions &LangOpts;
   std::vector<HighlightingToken> Tokens;
   std::map<Range, llvm::SmallVector<HighlightingModifier, 1>> ExtraModifiers;
-  const HeuristicResolver *Resolver;
+  const HeuristicResolver *Resolver = nullptr;
   // returned from addToken(InvalidLoc)
   HighlightingToken InvalidHighlightingToken;
 };