Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -13533,7 +13533,9 @@
       return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
     }
 
-    if (Info.Ctx.getLangOpts().CPlusPlus && DestType->isEnumeralType()) {
+    if (Info.Ctx.getLangOpts().CPlusPlus &&
+        Info.EvalMode == EvalInfo::EM_ConstantExpression &&
+        DestType->isEnumeralType()) {
       const EnumType *ET = dyn_cast<EnumType>(DestType.getCanonicalType());
       const EnumDecl *ED = ET->getDecl();
       // Check that the value is within the range of the enumeration values.