Implement DR1458: Taking the address of an object of incomplete class type is
not a constant expression, because we can't tell whether the complete class type
will have an overloaded operator&.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150066 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 4104067..48e0c6f 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -2937,6 +2937,18 @@
}
bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
+ QualType SrcTy = E->getSubExpr()->getType();
+ // In C++, taking the address of an object of incomplete class type has
+ // undefined behavior if the complete class type has an overloaded operator&.
+ // DR1458 makes such expressions non-constant.
+ if (Info.getLangOpts().CPlusPlus &&
+ SrcTy->isRecordType() && SrcTy->isIncompleteType()) {
+ const RecordType *RT = SrcTy->getAs<RecordType>();
+ Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_addr_of_incomplete, 1)
+ << SrcTy;
+ Info.Note(RT->getDecl()->getLocation(), diag::note_forward_declaration)
+ << RT->getDecl();
+ }
return EvaluateLValue(E->getSubExpr(), Result, Info);
}