[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 Bernd Edlinger changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |FIXED --- Comment #9 from Bernd Edlinger --- fixed on trunk.
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 --- Comment #8 from Bernd Edlinger --- Author: edlinger Date: Sat Nov 23 06:33:59 2019 New Revision: 278639 URL: https://gcc.gnu.org/viewcvs?rev=278639=gcc=rev Log: PR c++/92365 2019-11-22 Bernd Edlinger PR c++/92365 * name-lookup.c (check_local_shadow): Use can_convert_arg instead of can_convert. testsuite: 2019-11-22 Bernd Edlinger PR c++/92365 * g++.dg/pr92365.C: New test. Added: trunk/gcc/testsuite/g++.dg/pr92365.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/name-lookup.c trunk/gcc/testsuite/ChangeLog
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 --- Comment #7 from Martin Liška --- Just for the record, I see the failure in spatialindex package.
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365
--- Comment #6 from Bernd Edlinger ---
I tried this, and it contradicts what above comment says:
$ cat test1.cc
void foo()
{
char *x = int();
}
gcc -Wall -S -std=c++17 test1.cc
test1.cc: In function ‘void foo()’:
test1.cc:3:9: warning: unused variable ‘x’
[]8;;https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wunused-variable-Wunused-variable]8;;]
3 | char *x = int();
| ^
So I would have expected that to be rejected with c++11 and above
and accepted with c++98, but it is accepted with all C++ versions.
BTW: can we get rid of this URL-escapes in the warnings, soon?
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365
--- Comment #5 from Bernd Edlinger ---
Some insight, why the crash only happens with -std=c++98:
-Wshadow=compatible-local tries to find out if there is an
implicit conversion between the "int16_t f" and "a f".
The only candidate is a::a(char *);
The conversion is only allowed when it f is NULL.
/* [conv.ptr]
A null pointer constant can be converted to a pointer type; ... A
null pointer constant of integral type can be converted to an
rvalue of type std::nullptr_t. */
if ((tcode == POINTER_TYPE || TYPE_PTRMEM_P (to)
|| NULLPTR_TYPE_P (to))
&& ((expr && null_ptr_cst_p (expr))
|| NULLPTR_TYPE_P (from)))
conv = build_conv (ck_std, to, conv);
and now null_ptr_cst_p is invoked with "int16_t()", aka CAST_EXPR(NULL_TREE):
bool
null_ptr_cst_p (tree t)
{
tree type = TREE_TYPE (t);
/* [conv.ptr]
A null pointer constant is an integer literal ([lex.icon]) with value
zero or a prvalue of type std::nullptr_t. */
if (NULLPTR_TYPE_P (type))
return true;
if (cxx_dialect >= cxx11)
{
STRIP_ANY_LOCATION_WRAPPER (t);
/* Core issue 903 says only literal 0 is a null pointer constant. */
if (TREE_CODE (t) == INTEGER_CST
&& !TREE_OVERFLOW (t)
&& TREE_CODE (type) == INTEGER_TYPE
&& integer_zerop (t)
&& !char_type_p (type))
return true;
}
else if (CP_INTEGRAL_TYPE_P (type))
{
t = fold_non_dependent_expr (t, tf_none);
STRIP_NOPS (t);
if (integer_zerop (t) && !TREE_OVERFLOW (t))
return true;
}
return false;
and now fold_non_dependent_expr fails.
With above patch we enter with the t = f, the decl we want to cast,
it is obviously not null.
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 --- Comment #4 from Bernd Edlinger --- Created attachment 47180 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47180=edit possible fix This seems to fix the issue, although a fix in cxx_eval_constant_expression might be preferrable.
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org --- Comment #3 from Jakub Jelinek --- potential_constant_expression_1 handles CAST_EXPR (and *_CAST_EXPR), but cxx_evaluate_constant_expression doesn't. This is on a CAST_EXPR which has NULL first operand created by can_convert: /* implicit_conversion only considers user-defined conversions if it has an expression for the call argument list. */ if (CLASS_TYPE_P (from) || CLASS_TYPE_P (to)) arg = build1 (CAST_EXPR, from, NULL_TREE); In particular, NULL_TREE is considered to be a potential constant expression and we fall through into: return (RECUR (TREE_OPERAND (t, 0), !TYPE_REF_P (TREE_TYPE (t; in the CAST_EXPR: handling in potential_constant_expression_1, so return true.
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 --- Comment #2 from Bernd Edlinger --- This was a hidden bug: g++ -std=c++98 -Wshadow=compatible-local test.cc did ICE all the time.
[Bug c++/92365] [10 Regression] ice unexpected expression ‘int16_t()’ of kind cast_expr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92365 Marek Polacek changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2019-11-04 CC||mpolacek at gcc dot gnu.org Target Milestone|--- |10.0 Summary|ice unexpected expression |[10 Regression] ice |‘int16_t()’ of kind |unexpected expression |cast_expr |‘int16_t()’ of kind ||cast_expr Ever confirmed|0 |1 --- Comment #1 from Marek Polacek --- Started with r277643.
