r184043 - A quick fix to allow return type deduction on member templates

[Faisal Vali]

Hi Takumi,
     I'm not sure I understand.  Are you saying that when the current
snapshot of clang source is compiled with the most recent version of
clang (itself compiled from the most recent snapshot of clang trunk
source) - that the following error occurs?


> For example,
>
> clang/lib/Sema/AnalysisBasedWarnings.cpp:1126:7: error:
>       template argument uses local type '<anonymous enum at
>       clang/lib/Sema/AnalysisBasedWarnings.cpp:1105:5>'
>       [-Werror,-Wlocal-type-template-args]
>       << ObjectKind << D << FunctionKind
>       ^~
>
> Both ObjectKind and FunctionKind have anonymous local enum types.
>
> Any idea?

If so, i am quite puzzled.  It seems that it is emitting an error on
the code. If you look at the patch, it only affects function decls
(and really should be only template decls).
Are there any other errors/warnings that you think might be related -
i'll try and create a test file that creates such a warning with the
current clang trunk.
As far as options, you said only std=c++, right? anything else?
thank you!







>
> ...Takumi
>
>
> 2013/6/15 Faisal Vali <faisalv at yahoo.com>:
>> Author: faisalv
>> Date: Sat Jun 15 06:54:37 2013
>> New Revision: 184043
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=184043&view=rev
>> Log:
>> A quick fix to allow return type deduction on member templates
>> by ensuring DiagnoseUseOfDecl is called both on the found decl and the
>> decl being used (i.e the specialization in the case of member templates) whenever they are different.
>> Per the exchange captured in
>> http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20130610/081636.html
>> a more comprehensive fix that allows both decls to be passed into DiagnoseUseOfDecl is (or should be) forthcoming relatively soon.
>>
>>
>> Modified:
>>     cfe/trunk/lib/Sema/SemaOverload.cpp
>>     cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp
>>
>> Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=184043&r1=184042&r2=184043&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaOverload.cpp Sat Jun 15 06:54:37 2013
>> @@ -43,8 +43,15 @@ CreateFunctionRefExpr(Sema &S, FunctionD
>>                        SourceLocation Loc = SourceLocation(),
>>                        const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){
>>    if (S.DiagnoseUseOfDecl(FoundDecl, Loc))
>> +    return ExprError();
>> +  // If FoundDecl is different from Fn (such as if one is a template
>> +  // and the other a specialization), make sure DiagnoseUseOfDecl is
>> +  // called on both.
>> +  // FIXME: This would be more comprehensively addressed by modifying
>> +  // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
>> +  // being used.
>> +  if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc))
>>      return ExprError();
>> -
>>    DeclRefExpr *DRE = new (S.Context) DeclRefExpr(Fn, false, Fn->getType(),
>>                                                   VK_LValue, Loc, LocInfo);
>>    if (HadMultipleCandidates)
>> @@ -11001,6 +11008,15 @@ Sema::BuildCallToMemberFunction(Scope *S
>>        CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl);
>>        if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()))
>>          return ExprError();
>> +      // If FoundDecl is different from Method (such as if one is a template
>> +      // and the other a specialization), make sure DiagnoseUseOfDecl is
>> +      // called on both.
>> +      // FIXME: This would be more comprehensively addressed by modifying
>> +      // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
>> +      // being used.
>> +      if (Method != FoundDecl.getDecl() &&
>> +                      DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc()))
>> +        return ExprError();
>>        break;
>>
>>      case OR_No_Viable_Function:
>> @@ -11246,7 +11262,8 @@ Sema::BuildCallToObjectOfClassType(Scope
>>      CheckMemberOperatorAccess(LParenLoc, Object.get(), 0, Best->FoundDecl);
>>      if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc))
>>        return ExprError();
>> -
>> +    assert(Conv == Best->FoundDecl.getDecl() &&
>> +             "Found Decl & conversion-to-functionptr should be same, right?!");
>>      // We selected one of the surrogate functions that converts the
>>      // object parameter to a function pointer. Perform the conversion
>>      // on the object argument, then let ActOnCallExpr finish the job.
>>
>> Modified: cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp?rev=184043&r1=184042&r2=184043&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp Sat Jun 15 06:54:37 2013
>> @@ -339,5 +339,37 @@ namespace ExplicitInstantiationDecl {
>>    extern template auto f(int);
>>    int (*p)(int) = f;
>>  }
>> -
>> +namespace MemberTemplatesWithDeduction {
>> +  struct M {
>> +    template<class T> auto foo(T t) { return t; }
>> +    template<class T> auto operator()(T t) const { return t; }
>> +    template<class T> static __attribute__((unused)) int static_foo(T) {
>> +      return 5;
>> +    }
>> +    template<class T> operator T() { return T{}; }
>> +    operator auto() { return &static_foo<int>; }
>> +  };
>> +  struct N : M {
>> +    using M::foo;
>> +    using M::operator();
>> +    using M::static_foo;
>> +    using M::operator auto;
>> +  };
>> +
>> +  template <class T> int test() {
>> +    int i = T{}.foo(3);
>> +    T m = T{}.foo(M{});
>> +    int j = T{}(3);
>> +    M m2 = M{}(M{});
>> +    int k = T{}.static_foo(4);
>> +    int l = T::static_foo(5);
>> +    int l2 = T{};
>> +    struct X { };
>> +    X x = T{};
>> +    return 0;
>> +  }
>> +  int Minst = test<M>();
>> +  int Ninst = test<N>();
>> +
>> +}
>>  }
>>
>>
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