[clang] [clang] Reject using uninitialized reference in constant evaluation (PR #180923)

[Eli Friedman via cfe-commits]

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@@ -7150,8 +7150,20 @@ bool Compiler<Emitter>::VisitVectorUnaryOperator(const UnaryOperator *E) {
 
 template <class Emitter>
 bool Compiler<Emitter>::visitDeclRef(const ValueDecl *D, const Expr *E) {
-  if (DiscardResult)
-    return true;
+  if (DiscardResult) {
+    if (!(isa<VarDecl>(D) && D->getType()->isReferenceType()))
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efriedma-quic wrote:

Is a VarDecl the only relevant kind of decl here?

Even if VarDecl is currently the only relevant kind of decl, this seems like a bad way to structure the code; it's likely to get missed if a new kind of relevant decl gets added.

https://github.com/llvm/llvm-project/pull/180923