Re: C++ PATCH to forbid use of bool with the ++ operator

[Jason Merrill <jason at redhat dot com>]

OK, thanks.

On Wed, Sep 14, 2016 at 11:28 AM, Marek Polacek <polacek@redhat.com> wrote:
> On Tue, Sep 13, 2016 at 11:37:20PM -0400, Jason Merrill wrote:
>> On Tue, Sep 13, 2016 at 3:55 PM, Martin Sebor <msebor@gmail.com> wrote:
>> > Having said all that, since this is C++ the message could and
>> > arguably should refer to a bool expression (or type) instead
>> > and avoid having to deal with this altogether. In fact, it
>> > would be simpler to rephrase the message as:
>> >
>> >   "use of an operand of type %qT in ... is deprecated",
>> >   boolean_type_node
>>
>> Yes.
>
> Should be done in the patch below.
>
> Bootstrapped/regtested on x86_64-linux and ppc64-linux, ok for trunk?
>
> 2016-09-14  Marek Polacek  <polacek@redhat.com>
>
>         * typeck.c (cp_build_unary_op): Diagnose incrementing boolean
>         expressions.  Tweak an error message.
>
>         * c-c++-common/gomp/atomic-12.c: Use -Wno-deprecated.
>         * c-c++-common/gomp/atomic-13.c: Likewise.
>         * c-c++-common/gomp/atomic-14.c: Likewise.
>         * g++.dg/cpp1y/lambda-init11.C: Remove invalid code.
>         * g++.dg/cpp1z/bool-increment1.C: New test.
>         * c-c++-common/pr60439.c: Add dg-warning.
>         * g++.dg/expr/bitfield4.C: Likewise.
>         * g++.dg/expr/bitfield5.C: Likewise.
>         * g++.dg/expr/bitfield6.C: Likewise.
>         * g++.dg/expr/bool1.C: Likewise.
>         * g++.dg/expr/bool3.C: Likewise.
>         * g++.dg/expr/lval3.C: Likewise.
>         * g++.dg/expr/lval4.C: Likewise.
>         * g++.old-deja/g++.jason/bool5.C: Likewise.
>         * g++.dg/expr/bitfield3.C: Adjust dg-error.
>         * g++.dg/other/error18.C: Likewise.
>         * g++.dg/gomp/atomic-14.C: Likewise.
> libgomp/
>         * testsuite/libgomp.c++/atomic-3.C: Use -Wno-deprecated.
> libstdc++-v3/
>         * testsuite/23_containers/vector/debug/insert6_neg.cc: Use
>         -Wno-deprecated.
>
> diff --git gcc/gcc/cp/typeck.c gcc/gcc/cp/typeck.c
> index a591d29..808cb6c 100644
> --- gcc/gcc/cp/typeck.c
> +++ gcc/gcc/cp/typeck.c
> @@ -6030,16 +6030,32 @@ cp_build_unary_op (enum tree_code code, tree xarg, int noconvert,
>                               complain))
>           return error_mark_node;
>
> -       /* Forbid using -- on `bool'.  */
> +       /* Forbid using -- or ++ in C++17 on `bool'.  */
>         if (TREE_CODE (declared_type) == BOOLEAN_TYPE)
>           {
>             if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR)
>               {
>                  if (complain & tf_error)
> -                  error ("invalid use of Boolean expression as operand "
> -                         "to %<operator--%>");
> +                 error ("use of an operand of type %qT in %<operator--%> "
> +                        "is forbidden", boolean_type_node);
>                 return error_mark_node;
>               }
> +           else
> +             {
> +               if (cxx_dialect >= cxx1z)
> +                 {
> +                   if (complain & tf_error)
> +                     error ("use of an operand of type %qT in "
> +                            "%<operator++%> is forbidden in C++1z",
> +                            boolean_type_node);
> +                   return error_mark_node;
> +                 }
> +               /* Otherwise, [depr.incr.bool] says this is deprecated.  */
> +               else if (!in_system_header_at (input_location))
> +                 warning (OPT_Wdeprecated, "use of an operand of type %qT "
> +                          "in %<operator++%> is deprecated",
> +                          boolean_type_node);
> +             }
>             val = boolean_increment (code, arg);
>           }
>         else if (code == POSTINCREMENT_EXPR || code == POSTDECREMENT_EXPR)
> diff --git gcc/gcc/testsuite/c-c++-common/gomp/atomic-12.c gcc/gcc/testsuite/c-c++-common/gomp/atomic-12.c
> index 145e420..e9ca650 100644
> --- gcc/gcc/testsuite/c-c++-common/gomp/atomic-12.c
> +++ gcc/gcc/testsuite/c-c++-common/gomp/atomic-12.c
> @@ -1,6 +1,6 @@
>  /* PR middle-end/45423 */
>  /* { dg-do compile } */
> -/* { dg-options "-fopenmp -fdump-tree-gimple -g0" } */
> +/* { dg-options "-fopenmp -fdump-tree-gimple -g0 -Wno-deprecated" } */
>  /* atomicvar should never be referenced in between the barrier and
>     following #pragma omp atomic_load.  */
>  /* { dg-final { scan-tree-dump-not "barrier\[^#\]*atomicvar" "gimple" } } */
> diff --git gcc/gcc/testsuite/c-c++-common/gomp/atomic-13.c gcc/gcc/testsuite/c-c++-common/gomp/atomic-13.c
> index 2452035..7f4afcf 100644
> --- gcc/gcc/testsuite/c-c++-common/gomp/atomic-13.c
> +++ gcc/gcc/testsuite/c-c++-common/gomp/atomic-13.c
> @@ -1,6 +1,6 @@
>  /* PR middle-end/45423 */
>  /* { dg-do compile } */
> -/* { dg-options "-fopenmp -fdump-tree-gimple -g0 -O2" } */
> +/* { dg-options "-fopenmp -fdump-tree-gimple -g0 -O2 -Wno-deprecated" } */
>  /* atomicvar should never be referenced in between the barrier and
>     following #pragma omp atomic_load.  */
>  /* { dg-final { scan-tree-dump-not "barrier\[^#\]*atomicvar" "gimple" } } */
> diff --git gcc/gcc/testsuite/c-c++-common/gomp/atomic-14.c gcc/gcc/testsuite/c-c++-common/gomp/atomic-14.c
> index f8fc9d8..7e23453 100644
> --- gcc/gcc/testsuite/c-c++-common/gomp/atomic-14.c
> +++ gcc/gcc/testsuite/c-c++-common/gomp/atomic-14.c
> @@ -1,6 +1,6 @@
>  /* PR middle-end/45423 */
>  /* { dg-do compile } */
> -/* { dg-options "-fopenmp" } */
> +/* { dg-options "-fopenmp -Wno-deprecated" } */
>
>  #ifdef __cplusplus
>  bool *baz ();
> diff --git gcc/gcc/testsuite/c-c++-common/pr60439.c gcc/gcc/testsuite/c-c++-common/pr60439.c
> index 68bd33c..71b397a 100644
> --- gcc/gcc/testsuite/c-c++-common/pr60439.c
> +++ gcc/gcc/testsuite/c-c++-common/pr60439.c
> @@ -132,6 +132,7 @@ f6 (bool b)
>        break;
>      }
>    switch (b++) /* { dg-warning "switch condition has" } */
> +  /* { dg-warning "is deprecated" "" { target c++ } 134 } */
>      {
>      case 3:
>        break;
> diff --git gcc/gcc/testsuite/g++.dg/cpp1y/lambda-init11.C gcc/gcc/testsuite/g++.dg/cpp1y/lambda-init11.C
> index f7525d8..4d434cd 100644
> --- gcc/gcc/testsuite/g++.dg/cpp1y/lambda-init11.C
> +++ gcc/gcc/testsuite/g++.dg/cpp1y/lambda-init11.C
> @@ -16,5 +16,4 @@ int main(){
>    foo(3.14f);
>    foo(0);
>    foo('a');
> -  foo(false);
>  }
> diff --git gcc/gcc/testsuite/g++.dg/cpp1z/bool-increment1.C gcc/gcc/testsuite/g++.dg/cpp1z/bool-increment1.C
> index e69de29..ae2dcf9 100644
> --- gcc/gcc/testsuite/g++.dg/cpp1z/bool-increment1.C
> +++ gcc/gcc/testsuite/g++.dg/cpp1z/bool-increment1.C
> @@ -0,0 +1,14 @@
> +// { dg-options -std=c++1z }
> +
> +int
> +fn (bool b)
> +{
> +  int r = 0;
> +
> +  r += b++; // { dg-error "use of an operand of type .bool. in .operator\\+\\+. is forbidden in" }
> +  r += ++b; // { dg-error "use of an operand of type .bool. in .operator\\+\\+. is forbidden in" }
> +  r += b--; // { dg-error "use of an operand of type .bool. in .operator--. is forbidden" }
> +  r += --b; // { dg-error "use of an operand of type .bool. in .operator--. is forbidden" }
> +
> +  return r;
> +}
> diff --git gcc/gcc/testsuite/g++.dg/expr/bitfield3.C gcc/gcc/testsuite/g++.dg/expr/bitfield3.C
> index 3221263..3f30337 100644
> --- gcc/gcc/testsuite/g++.dg/expr/bitfield3.C
> +++ gcc/gcc/testsuite/g++.dg/expr/bitfield3.C
> @@ -7,6 +7,6 @@ struct S {
>  S s;
>
>  void f() {
> -  s.x--; // { dg-error "Boolean expression" }
> -  --s.x; // { dg-error "Boolean expression" }
> +  s.x--; // { dg-error "use of an operand of type .bool." }
> +  --s.x; // { dg-error "use of an operand of type .bool." }
>  }
> diff --git gcc/gcc/testsuite/g++.dg/expr/bitfield4.C gcc/gcc/testsuite/g++.dg/expr/bitfield4.C
> index d824964..7fae086 100644
> --- gcc/gcc/testsuite/g++.dg/expr/bitfield4.C
> +++ gcc/gcc/testsuite/g++.dg/expr/bitfield4.C
> @@ -14,6 +14,6 @@ template <>
>  void f(bool) {}
>
>  int main() {
> -  f(s.x++);
> -  f(++s.x);
> +  f(s.x++); // { dg-warning "deprecated" }
> +  f(++s.x); // { dg-warning "deprecated" }
>  }
> diff --git gcc/gcc/testsuite/g++.dg/expr/bitfield5.C gcc/gcc/testsuite/g++.dg/expr/bitfield5.C
> index 3d18e15..0a37f9f 100644
> --- gcc/gcc/testsuite/g++.dg/expr/bitfield5.C
> +++ gcc/gcc/testsuite/g++.dg/expr/bitfield5.C
> @@ -8,10 +8,10 @@ struct S {
>  S s;
>
>  int main() {
> -  s.x++;
> +  s.x++; // { dg-warning "deprecated" }
>    if (s.x != 1)
>      return 1;
> -  ++s.x;
> +  ++s.x; // { dg-warning "deprecated" }
>    if (s.x != 1)
>      return 2;
>  }
> diff --git gcc/gcc/testsuite/g++.dg/expr/bitfield6.C gcc/gcc/testsuite/g++.dg/expr/bitfield6.C
> index 6f6d559..8523866 100644
> --- gcc/gcc/testsuite/g++.dg/expr/bitfield6.C
> +++ gcc/gcc/testsuite/g++.dg/expr/bitfield6.C
> @@ -7,5 +7,5 @@ struct S {
>  S s;
>
>  void f() {
> -  ++s.x = false;
> +  ++s.x = false; // { dg-warning "deprecated" }
>  }
> diff --git gcc/gcc/testsuite/g++.dg/expr/bool1.C gcc/gcc/testsuite/g++.dg/expr/bool1.C
> index bfb40e3..503e8b4 100644
> --- gcc/gcc/testsuite/g++.dg/expr/bool1.C
> +++ gcc/gcc/testsuite/g++.dg/expr/bool1.C
> @@ -10,8 +10,8 @@ int main()
>    my_bool b = false;
>    int i;
>
> -  b++;
> -  b++;
> +  b++; // { dg-warning "deprecated" }
> +  b++; // { dg-warning "deprecated" }
>    i = b;
>    if (i != 1)
>      abort ();
> diff --git gcc/gcc/testsuite/g++.dg/expr/bool3.C gcc/gcc/testsuite/g++.dg/expr/bool3.C
> index 61669e2..1866ed4 100644
> --- gcc/gcc/testsuite/g++.dg/expr/bool3.C
> +++ gcc/gcc/testsuite/g++.dg/expr/bool3.C
> @@ -10,8 +10,8 @@ int main()
>    my_bool b = false;
>    int i;
>
> -  b++;
> -  b++;
> +  b++; // { dg-warning "deprecated" }
> +  b++; // { dg-warning "deprecated" }
>    i = b;
>    if (i != 1)
>      abort ();
> diff --git gcc/gcc/testsuite/g++.dg/expr/lval3.C gcc/gcc/testsuite/g++.dg/expr/lval3.C
> index f106e69..8e0aead 100644
> --- gcc/gcc/testsuite/g++.dg/expr/lval3.C
> +++ gcc/gcc/testsuite/g++.dg/expr/lval3.C
> @@ -4,6 +4,7 @@ f()
>  {
>    bool i = 0;
>    i++ = 3; // { dg-error "" }
> +  // { dg-warning "deprecated" "" { target *-*-* } 6 }
>  }
>
>
> diff --git gcc/gcc/testsuite/g++.dg/expr/lval4.C gcc/gcc/testsuite/g++.dg/expr/lval4.C
> index c66e2f6..b903ec8 100644
> --- gcc/gcc/testsuite/g++.dg/expr/lval4.C
> +++ gcc/gcc/testsuite/g++.dg/expr/lval4.C
> @@ -4,6 +4,7 @@ f()
>  {
>    bool i = 0;
>    ++i = 3;
> +  // { dg-warning "deprecated" "" { target *-*-* } 6 }
>  }
>
>
> diff --git gcc/gcc/testsuite/g++.dg/gomp/atomic-14.C gcc/gcc/testsuite/g++.dg/gomp/atomic-14.C
> index ae1eb50..982f44f 100644
> --- gcc/gcc/testsuite/g++.dg/gomp/atomic-14.C
> +++ gcc/gcc/testsuite/g++.dg/gomp/atomic-14.C
> @@ -8,12 +8,12 @@ int
>  foo (void)
>  {
>    #pragma omp atomic
> -    (*baz ())--;       // { dg-error "invalid use of Boolean" }
> +    (*baz ())--;       // { dg-error "use of an operand of type .bool." }
>    #pragma omp atomic
> -    --(*baz ());       // { dg-error "invalid use of Boolean" }
> +    --(*baz ());       // { dg-error "use of an operand of type .bool." }
>    #pragma omp atomic
> -    atomicvar--;       // { dg-error "invalid use of Boolean" }
> +    atomicvar--;       // { dg-error "use of an operand of type .bool." }
>    #pragma omp atomic
> -    --atomicvar;       // { dg-error "invalid use of Boolean" }
> +    --atomicvar;       // { dg-error "use of an operand of type .bool." }
>    return 0;
>  }
> diff --git gcc/gcc/testsuite/g++.dg/other/error18.C gcc/gcc/testsuite/g++.dg/other/error18.C
> index 9e4d21c..05ddf11 100644
> --- gcc/gcc/testsuite/g++.dg/other/error18.C
> +++ gcc/gcc/testsuite/g++.dg/other/error18.C
> @@ -7,5 +7,5 @@ struct A
>
>  void f(A a)
>  {
> -  a.b--; // { dg-error "Boolean expression" }
> +  a.b--; // { dg-error "use of an operand of type .bool." }
>  }
> diff --git gcc/gcc/testsuite/g++.old-deja/g++.jason/bool5.C gcc/gcc/testsuite/g++.old-deja/g++.jason/bool5.C
> index 1d2f5b6..0a16ccb 100644
> --- gcc/gcc/testsuite/g++.old-deja/g++.jason/bool5.C
> +++ gcc/gcc/testsuite/g++.old-deja/g++.jason/bool5.C
> @@ -2,10 +2,10 @@
>  int main ()
>  {
>    bool b = false;
> -  int i = b++;
> +  int i = b++; // { dg-warning "deprecated" }
>    if (i != false || b != true)
>      return 1;
> -  i = b++;
> +  i = b++; // { dg-warning "deprecated" }
>    if (i != true || b != true)
>      return 1;
>  }
> diff --git gcc/libgomp/testsuite/libgomp.c++/atomic-3.C gcc/libgomp/testsuite/libgomp.c++/atomic-3.C
> index 660b260..f957b2f 100644
> --- gcc/libgomp/testsuite/libgomp.c++/atomic-3.C
> +++ gcc/libgomp/testsuite/libgomp.c++/atomic-3.C
> @@ -1,4 +1,5 @@
>  // { dg-do run }
> +// { dg-options "-Wno-deprecated" }
>
>  extern "C" void abort (void);
>  bool v, x1, x2, x3, x4, x5, x6;
> diff --git gcc/libstdc++-v3/testsuite/23_containers/vector/debug/insert6_neg.cc gcc/libstdc++-v3/testsuite/23_containers/vector/debug/insert6_neg.cc
> index 9893293..c939c22 100644
> --- gcc/libstdc++-v3/testsuite/23_containers/vector/debug/insert6_neg.cc
> +++ gcc/libstdc++-v3/testsuite/23_containers/vector/debug/insert6_neg.cc
> @@ -16,6 +16,7 @@
>  // <http://www.gnu.org/licenses/>.
>  //
>  // { dg-do run { xfail *-*-* } }
> +// { dg-options "-Wno-deprecated" }
>
>  #include <vector>
>  #include <debug/vector>
>
>         Marek