[clang] [Clang] Fixed UnresolvedLookupExpr propagating into the codegen phase (PR #124609)

[Erich Keane via cfe-commits]

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@@ -703,6 +703,48 @@ auto f(auto x) { // cxx14-error {{'auto' not allowed in function prototype}}
   return f(1) + 1;
 }
 
+namespace GH122892 {
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erichkeane wrote:

Yeah, so this patch now prevents an `UnresolvedLookupExpr` from being put into the AST for a non-dependent function.  The symptom of that (besides the AST-dump) was that CodeGen didn't know how to handle that for obvious reasons.

This patch is now preventing that `UnresolvedLookupExpr` from being put into the AST for non-dependent functions, and falls-thru to emitting an error.

I Think.

https://github.com/llvm/llvm-project/pull/124609