[clang] [compiler-rt] [clang][UBSan] Add implicit conversion check for bitfields (PR #75481)

[Richard Smith via cfe-commits]

================
@@ -555,13 +555,11 @@ static void handleImplicitConversion(ImplicitConversionData *Data,
                                      ReportOptions Opts, ValueHandle Src,
                                      ValueHandle Dst) {
   SourceLocation Loc = Data->Loc.acquire();
-  ErrorType ET = ErrorType::GenericUB;
-
   const TypeDescriptor &SrcTy = Data->FromType;
   const TypeDescriptor &DstTy = Data->ToType;
-
   bool SrcSigned = SrcTy.isSignedIntegerTy();
   bool DstSigned = DstTy.isSignedIntegerTy();
+  ErrorType ET = ErrorType::GenericUB;
----------------
zygoloid wrote:

This seems suspect, given that this handler is detecting things that aren't UB.

https://github.com/llvm/llvm-project/pull/75481