On Mon, Nov 13, 2023 at 10:59:52PM -0500, Jason Merrill wrote:
On 11/13/23 06:50, Jakub Jelinek wrote:
The following patch implements C++26 P2864R2 by emitting pedwarn enabled by
the same options as the C++20 and later warnings (i.e. -Wenum-compare,
-Wdeprecated-enum-enum-conversion and -Wdeprecated-enum-float-conversion
which are all enabled by default). I think we still want to allow users
some option workaround, so am not using directly error, but if that is
what you want instead, I can change it.
I agree, but we also need to return error_mark_node for these cases when
SFINAE, i.e. !(complain & tf_warning_or_error)
So like this then?
Bootstrapped/regtested on x86_64-linux and i686-linux.
2023-11-14 Jakub Jelinek <ja...@redhat.com>
gcc/cp/
* typeck.cc: Implement C++26 P2864R2 - Remove Deprecated Arithmetic
Conversion on Enumerations From C++26.
(do_warn_enum_conversions): Return bool rather than void, add COMPLAIN
argument. Use pedwarn rather than warning_at for C++26 and remove
" is deprecated" part of the diagnostics in that case. For SFINAE
in C++26 return true on newly erroneous cases.
(cp_build_binary_op): For C++26 call do_warn_enum_conversions
unconditionally, pass complain argument to it and if it returns true,
return error_mark_node.
* call.cc (build_conditional_expr): Use pedwarn rather than warning_at
for C++26 and remove " is deprecated" part of the diagnostics in that
case and check for complain & tf_warning_or_error. Use emit_diagnostic
with cxx_dialect >= cxx26 ? DK_PEDWARN : DK_WARNING. For SFINAE in
C++26 return error_mark_node on newly erroneous cases.
(build_new_op): Use emit_diagnostic with cxx_dialect >= cxx26
? DK_PEDWARN : DK_WARNING and complain & tf_warning_or_error check
for C++26. For SFINAE in C++26 return error_mark_node on newly
erroneous cases.
gcc/testsuite/
* g++.dg/cpp26/enum-conv1.C: New test.
* g++.dg/cpp2a/enum-conv1.C: Adjust expected diagnostics in C++26.
* g++.dg/diagnostic/enum3.C: Likewise.
* g++.dg/parse/attr3.C: Likewise.
* g++.dg/cpp0x/linkage2.C: Likewise.
--- gcc/cp/typeck.cc.jj 2023-11-13 13:02:21.573785549 +0100
+++ gcc/cp/typeck.cc 2023-11-14 09:49:31.026997048 +0100
@@ -4940,16 +4940,25 @@ warn_for_null_address (location_t locati
type, this behavior is deprecated ([depr.arith.conv.enum]). CODE is the
code of the binary operation, TYPE0 and TYPE1 are the types of the
operands,
and LOC is the location for the whole binary expression.
+ For C++26 this is ill-formed rather than deprecated.
+ Return true for SFINAE errors.
TODO: Consider combining this with -Wenum-compare in build_new_op_1. */
-static void
+static bool
do_warn_enum_conversions (location_t loc, enum tree_code code, tree type0,
- tree type1)
+ tree type1, tsubst_flags_t complain)
{
if (TREE_CODE (type0) == ENUMERAL_TYPE
&& TREE_CODE (type1) == ENUMERAL_TYPE
&& TYPE_MAIN_VARIANT (type0) != TYPE_MAIN_VARIANT (type1))
{
+ if (cxx_dialect >= cxx26)
+ {
+ if ((complain & tf_warning_or_error) == 0)
+ return true;
+ }
+ else if ((complain & tf_warning) == 0)
+ return false;
/* In C++20, -Wdeprecated-enum-enum-conversion is on by default.
Otherwise, warn if -Wenum-conversion is on. */
enum opt_code opt;
@@ -4958,7 +4967,7 @@ do_warn_enum_conversions (location_t loc
else if (warn_enum_conversion)
opt = OPT_Wenum_conversion;
else
- return;
+ return false;
switch (code)
{
@@ -4969,21 +4978,29 @@ do_warn_enum_conversions (location_t loc
case EQ_EXPR:
case NE_EXPR:
/* Comparisons are handled by -Wenum-compare. */
- return;
+ return false;
case SPACESHIP_EXPR:
/* This is invalid, don't warn. */
- return;
+ return false;
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
case BIT_XOR_EXPR:
- warning_at (loc, opt, "bitwise operation between different "
- "enumeration types %qT and %qT is deprecated",
- type0, type1);
- return;
+ if (cxx_dialect >= cxx26)
+ pedwarn (loc, opt, "bitwise operation between different "
+ "enumeration types %qT and %qT", type0, type1);
+ else
+ warning_at (loc, opt, "bitwise operation between different "
+ "enumeration types %qT and %qT is deprecated",
+ type0, type1);
+ return false;
default:
- warning_at (loc, opt, "arithmetic between different enumeration "
- "types %qT and %qT is deprecated", type0, type1);
- return;
+ if (cxx_dialect >= cxx26)
+ pedwarn (loc, opt, "arithmetic between different enumeration "
+ "types %qT and %qT", type0, type1);
+ else
+ warning_at (loc, opt, "arithmetic between different enumeration "
+ "types %qT and %qT is deprecated", type0, type1);
+ return false;
}
}
else if ((TREE_CODE (type0) == ENUMERAL_TYPE
@@ -4991,6 +5008,13 @@ do_warn_enum_conversions (location_t loc
|| (SCALAR_FLOAT_TYPE_P (type0)
&& TREE_CODE (type1) == ENUMERAL_TYPE))
{
+ if (cxx_dialect >= cxx26)
+ {
+ if ((complain & tf_warning_or_error) == 0)
+ return true;
+ }
+ else if ((complain & tf_warning) == 0)
+ return false;
const bool enum_first_p = TREE_CODE (type0) == ENUMERAL_TYPE;
/* In C++20, -Wdeprecated-enum-float-conversion is on by default.
Otherwise, warn if -Wenum-conversion is on. */
@@ -5000,7 +5024,7 @@ do_warn_enum_conversions (location_t loc
else if (warn_enum_conversion)
opt = OPT_Wenum_conversion;
else
- return;
+ return false;
switch (code)
{
@@ -5010,7 +5034,13 @@ do_warn_enum_conversions (location_t loc
case LE_EXPR:
case EQ_EXPR:
case NE_EXPR:
- if (enum_first_p)
+ if (enum_first_p && cxx_dialect >= cxx26)
+ pedwarn (loc, opt, "comparison of enumeration type %qT with "
+ "floating-point type %qT", type0, type1);
+ else if (cxx_dialect >= cxx26)
+ pedwarn (loc, opt, "comparison of floating-point type %qT "
+ "with enumeration type %qT", type0, type1);
+ else if (enum_first_p)
warning_at (loc, opt, "comparison of enumeration type %qT with "
"floating-point type %qT is deprecated",
type0, type1);
@@ -5018,12 +5048,18 @@ do_warn_enum_conversions (location_t loc
warning_at (loc, opt, "comparison of floating-point type %qT "
"with enumeration type %qT is deprecated",
type0, type1);
- return;
+ return false;
case SPACESHIP_EXPR:
/* This is invalid, don't warn. */
- return;
+ return false;
default:
- if (enum_first_p)
+ if (enum_first_p && cxx_dialect >= cxx26)
+ pedwarn (loc, opt, "arithmetic between enumeration type %qT "
+ "and floating-point type %qT", type0, type1);
+ else if (cxx_dialect >= cxx26)
+ pedwarn (loc, opt, "arithmetic between floating-point type %qT "
+ "and enumeration type %qT", type0, type1);
+ else if (enum_first_p)
warning_at (loc, opt, "arithmetic between enumeration type %qT "
"and floating-point type %qT is deprecated",
type0, type1);
@@ -5031,9 +5067,10 @@ do_warn_enum_conversions (location_t loc
warning_at (loc, opt, "arithmetic between floating-point type %qT "
"and enumeration type %qT is deprecated",
type0, type1);
- return;
+ return true;
