Index: clang-tools-extra/trunk/clangd/SemanticHighlighting.cpp
===================================================================
--- clang-tools-extra/trunk/clangd/SemanticHighlighting.cpp
+++ clang-tools-extra/trunk/clangd/SemanticHighlighting.cpp
@@ -52,6 +52,10 @@
       // When calling the destructor manually like: AAA::~A(); The ~ is a
       // MemberExpr. Other methods should still be highlighted though.
       return true;
+    if (isa<CXXConversionDecl>(MD))
+      // The MemberLoc is invalid for C++ conversion operators. We do not
+      // attempt to add tokens with invalid locations.
+      return true;
     addToken(ME->getMemberLoc(), MD);
     return true;
   }
Index: clang-tools-extra/trunk/clangd/unittests/SemanticHighlightingTests.cpp
===================================================================
--- clang-tools-extra/trunk/clangd/unittests/SemanticHighlightingTests.cpp
+++ clang-tools-extra/trunk/clangd/unittests/SemanticHighlightingTests.cpp
@@ -255,6 +255,23 @@
       struct $Class[[Tmpl]] {$TemplateParameter[[T]] $Field[[x]] = 0;};
       extern template struct $Class[[Tmpl]]<float>;
       template struct $Class[[Tmpl]]<double>;
+    )cpp",
+    // This test is to guard against highlightings disappearing when using
+    // conversion operators as their behaviour in the clang AST differ from
+    // other CXXMethodDecls.
+    R"cpp(
+      class $Class[[Foo]] {};
+      struct $Class[[Bar]] {
+        explicit operator $Class[[Foo]]*() const;
+        explicit operator int() const;
+        operator $Class[[Foo]]();
+      };
+      void $Function[[f]]() {
+        $Class[[Bar]] $Variable[[B]];
+        $Class[[Foo]] $Variable[[F]] = $Variable[[B]];
+        $Class[[Foo]] *$Variable[[FP]] = ($Class[[Foo]]*)$Variable[[B]];
+        int $Variable[[I]] = (int)$Variable[[B]];
+      }
     )cpp"};
   for (const auto &TestCase : TestCases) {
     checkHighlightings(TestCase);