[cfe-commits] r125714 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaExpr.cpp test/SemaCXX/member-expr.cpp

[Douglas Gregor]

On Feb 16, 2011, at 6:54 PM, Matt Beaumont-Gay wrote:

> Author: matthewbg
> Date: Wed Feb 16 20:54:17 2011
> New Revision: 125714
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=125714&view=rev
> Log:
> Fix PR9025 and add a diagnostic (and sometimes a fixit) for an overloaded
> function name used as the base of a member expression. Early feedback from
> Chandler Carruth, and code review from Nick Lewycky.

Thanks for working on this. A few comments below...

> Modified:
>    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>    cfe/trunk/lib/Sema/SemaExpr.cpp
>    cfe/trunk/test/SemaCXX/member-expr.cpp
> 
> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=125714&r1=125713&r2=125714&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Feb 16 20:54:17 2011
> @@ -2364,6 +2364,11 @@
> def err_typecheck_member_reference_unknown : Error<
>   "cannot refer to member %0 in %1 with '%select{.|->}2'">;
> def err_member_reference_needs_call : Error<
> +  "base of member reference is an overloaded function; perhaps you meant "
> +  "to call %select{it|the 0-argument overload}0?">;
> +def note_member_ref_possible_intended_overload : Note<
> +  "possibly valid overload here">;
> +def err_member_reference_needs_call_zero_arg : Error<
>   "base of member reference has function type %0; perhaps you meant to call "
>   "this function with '()'?">;
> def warn_subscript_is_char : Warning<"array subscript is of type 'char'">,
> 
> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=125714&r1=125713&r2=125714&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Wed Feb 16 20:54:17 2011
> @@ -3995,6 +3995,8 @@
> 
>   // There's a possible road to recovery for function types.
>   const FunctionType *Fun = 0;
> +  SourceLocation ParenInsertionLoc =
> +      PP.getLocForEndOfToken(BaseExpr->getLocEnd());
> 
>   if (const PointerType *Ptr = BaseType->getAs<PointerType>()) {
>     if ((Fun = Ptr->getPointeeType()->getAs<FunctionType>())) {
> @@ -4029,7 +4031,53 @@
>   if (Fun || BaseType == Context.OverloadTy) {
>     bool TryCall;
>     if (BaseType == Context.OverloadTy) {
> -      TryCall = true;
> +      // Plunder the overload set for something that would make the member
> +      // expression valid.
> +      const OverloadExpr *Overloads = cast<OverloadExpr>(BaseExpr);
> +      UnresolvedSet<4> CandidateOverloads;
> +      bool HasZeroArgCandidateOverload = false;
> +      for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
> +           DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
> +        const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*it);
> +        QualType ResultTy = OverloadDecl->getResultType();
> +        if ((!IsArrow && ResultTy->isRecordType()) ||
> +            (IsArrow && ResultTy->isPointerType() &&
> +             ResultTy->getPointeeType()->isRecordType())) {
> +          CandidateOverloads.addDecl(*it);
> +          if (OverloadDecl->getNumParams() == 0) {
> +            HasZeroArgCandidateOverload = true;
> +          }

OverloadDecl->getMinRequiredArguments() == 0 would be better here, since it accounts for parameter packs and default arguments.

Overall, it would be great to pull the "find a function that we could call with ()" logic out into a subroutine, because there are probably a number of other places where we'd like to have the same kind of recovery.

	- Doug