[clang] Add error check for HeuristicResolver (PR #155561)

[Mythreya Kuricheti via cfe-commits]

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@@ -42,6 +62,11 @@ template <typename InputNode, typename ParamT, typename InputMatcher,
 void expectResolution(llvm::StringRef Code, ResolveFnT<ParamT> ResolveFn,
                       const InputMatcher &IM, const OutputMatchers &...OMS) {
   auto TU = tooling::buildASTFromCodeWithArgs(Code, {"-std=c++23"});
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MythreyaK wrote:

omg totally forgot about this, sorry! 

https://github.com/llvm/llvm-project/pull/155561