[PATCH] D141954: Forbid implicit conversion of constraint expression to bool

[Tom Honermann via Phabricator via cfe-commits]

tahonermann added inline comments.


================
Comment at: clang/lib/Sema/SemaConcept.cpp:377-380
+          SubstitutedExpression = ImplicitCastExpr::Create(
+              S.Context, SubstitutedExpression.get()->getType(),
+              CK_LValueToRValue, SubstitutedExpression.get(),
+              /*BasePath=*/nullptr, VK_PRValue, FPOptionsOverride());
----------------
erichkeane wrote:
> tahonermann wrote:
> > `ImplicitCastExpr::Create()` has the following assertion. I wonder if we need to guard against this here.
> >   clang/lib/AST/Expr.cpp:
> >   2073   assert((Kind != CK_LValueToRValue ||
> >   2074           !(T->isNullPtrType() || T->getAsCXXRecordDecl())) &&
> >   2075          "invalid type for lvalue-to-rvalue conversion");
> > 
> > Or perhaps it would be better to call `Sema::DefaultLvalueConversion()` here?
> I don't think we want all the baggage that DefaultLvalueConversion gets us, including diagnostics/etc.  That assert IS concerning though... I presume we can come up with something to hit that. 
> 
> It DOES look like that DefeaultLValue conversion replaces the nullptrtypes with a NullToPointer cast, so perhaps I should do that, and doesn't do anything with a record type.
I'm surprised the additional checks for `nullptr` aren't tripping that assert; it looks to me like it should. Any ideas?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D141954/new/

https://reviews.llvm.org/D141954