r329804 - [Sema] Fix built-in decrement operator overload resolution

[Jan Korous via cfe-commits]

Hi Richard,

Here you are:
https://reviews.llvm.org/D45569 <https://reviews.llvm.org/D45569>

I am now thinking if it makes sense to output this warning for pre-17 standards:

warning: incrementing expression of type bool is deprecated and incompatible with C++17

Produced in:

SemaExpr.cpp

static QualType CheckIncrementDecrementOperand

    // Increment of bool sets it to true, but is deprecated.
    S.Diag(OpLoc, S.getLangOpts().CPlusPlus17 ? diag::ext_increment_bool
                                              : diag::warn_increment_bool)

What do you think?

Jan

> On 11 Apr 2018, at 15:19, Richard Smith <richard at metafoo.co.uk> wrote:
> 
> While you're here... ++ should not be available for bool in C++17 onwards. :)
> 
> On Wed, 11 Apr 2018, 14:39 Jan Korous via cfe-commits, <cfe-commits at lists.llvm.org <mailto:cfe-commits at lists.llvm.org>> wrote:
> Author: jkorous
> Date: Wed Apr 11 06:36:29 2018
> New Revision: 329804
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=329804&view=rev <http://llvm.org/viewvc/llvm-project?rev=329804&view=rev>
> Log:
> [Sema] Fix built-in decrement operator overload resolution
> 
> C++ [over.built] p4:
> 
> "For every pair (T, VQ), where T is an arithmetic type other than bool, and VQ is either volatile or empty, there exist candidate operator functions of the form
> 
>   VQ T&      operator--(VQ T&);
>   T          operator--(VQ T&, int);
> "
> The bool type is in position LastPromotedIntegralType in BuiltinOperatorOverloadBuilder::getArithmeticType::ArithmeticTypes, but addPlusPlusMinusMinusArithmeticOverloads() was expecting it at position 0.
> 
> Differential Revision: https://reviews.llvm.org/D44988 <https://reviews.llvm.org/D44988>
> 
> rdar://problem/34255516
> 
> Modified:
>     cfe/trunk/lib/Sema/SemaOverload.cpp
>     cfe/trunk/test/SemaCXX/overloaded-builtin-operators.cpp
> 
> Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=329804&r1=329803&r2=329804&view=diff <http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=329804&r1=329803&r2=329804&view=diff>
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaOverload.cpp Wed Apr 11 06:36:29 2018
> @@ -7796,10 +7796,12 @@ public:
>      if (!HasArithmeticOrEnumeralCandidateType)
>        return;
> 
> -    for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1);
> -         Arith < NumArithmeticTypes; ++Arith) {
> +    for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) {
> +      const auto TypeOfT = ArithmeticTypes[Arith];
> +      if (Op == OO_MinusMinus && TypeOfT == S.Context.BoolTy)
> +        continue;
>        addPlusPlusMinusMinusStyleOverloads(
> -        ArithmeticTypes[Arith],
> +        TypeOfT,
>          VisibleTypeConversionsQuals.hasVolatile(),
>          VisibleTypeConversionsQuals.hasRestrict());
>      }
> 
> Modified: cfe/trunk/test/SemaCXX/overloaded-builtin-operators.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/overloaded-builtin-operators.cpp?rev=329804&r1=329803&r2=329804&view=diff <http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/overloaded-builtin-operators.cpp?rev=329804&r1=329803&r2=329804&view=diff>
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/overloaded-builtin-operators.cpp (original)
> +++ cfe/trunk/test/SemaCXX/overloaded-builtin-operators.cpp Wed Apr 11 06:36:29 2018
> @@ -62,6 +62,10 @@ void f(Short s, Long l, Enum1 e1, Enum2
>    // FIXME: should pass (void)static_cast<no&>(islong(e1 % e2));
>  }
> 
> +struct BoolRef {
> +  operator bool&();
> +};
> +
>  struct ShortRef { // expected-note{{candidate function (the implicit copy assignment operator) not viable}}
>  #if __cplusplus >= 201103L // C++11 or later
>  // expected-note at -2 {{candidate function (the implicit move assignment operator) not viable}}
> @@ -73,6 +77,10 @@ struct LongRef {
>    operator volatile long&();
>  };
> 
> +struct FloatRef {
> +  operator float&();
> +};
> +
>  struct XpmfRef { // expected-note{{candidate function (the implicit copy assignment operator) not viable}}
>  #if __cplusplus >= 201103L // C++11 or later
>  // expected-note at -2 {{candidate function (the implicit move assignment operator) not viable}}
> @@ -84,13 +92,19 @@ struct E2Ref {
>    operator E2&();
>  };
> 
> -void g(ShortRef sr, LongRef lr, E2Ref e2_ref, XpmfRef pmf_ref) {
> +void g(BoolRef br, ShortRef sr, LongRef lr, FloatRef fr, E2Ref e2_ref, XpmfRef pmf_ref) {
>    // C++ [over.built]p3
>    short s1 = sr++;
> 
> -  // C++ [over.built]p3
> +  // C++ [over.built]p4
>    long l1 = lr--;
> 
> +  // C++ [over.built]p4
> +  float f1 = fr--;
> +
> +  // C++ [over.built]p4
> +  bool b2 = br--; // expected-error{{cannot decrement value of type 'BoolRef'}}
> +
>    // C++ [over.built]p18
>    short& sr1 = (sr *= lr);
>    volatile long& lr1 = (lr *= sr);
> 
> 
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