[clang] [Clang][Sema] Fix type of enumerators in incomplete enumerations (PR #84068)

[via cfe-commits]

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@@ -264,10 +264,13 @@ namespace {
 }
 
 QualType Expr::getEnumCoercedType(const ASTContext &Ctx) const {
-  if (isa<EnumType>(this->getType()))
+  if (isa<EnumType>(this->getType())) {
     return this->getType();
-  else if (const auto *ECD = this->getEnumConstantDecl())
-    return Ctx.getTypeDeclType(cast<EnumDecl>(ECD->getDeclContext()));
+  } else if (const auto *ECD = this->getEnumConstantDecl()) {
+    const auto *ED = cast<EnumDecl>(ECD->getDeclContext());
+    if (ED->isCompleteDefinition())
+      return Ctx.getTypeDeclType(ED);
+  }
   return this->getType();
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Kupa-Martin wrote:

Force of habit. I already changed it.

https://github.com/llvm/llvm-project/pull/84068