[Bug c++/86692] New: Too lenient parsing of noptr-new-declarator
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86692
Bug ID: 86692
Summary: Too lenient parsing of noptr-new-declarator
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/*** BEGIN SOURCE ***/
int main() {
int n = 1;
auto p = new int[n][2, 3];
}
/ END SOURCE /
This compiles without errors, but `2, 3` is not a constant-expression
(conditional-expression) as required by the grammar production for
noptr-new-declarator in [expr.new]. This leniency has some potential for
confusion as someone could interpret `2, 3` as dimensions of a
multi-dimensional array, rather than the comma operator. For comparison, clang
correctly reports a syntax error here.
Checked in build 9.0.0 20180725 (experimental)
[Bug c++/86717] New: Unexpected error in dynamic allocation of an array of function pointers
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86717
Bug ID: 86717
Summary: Unexpected error in dynamic allocation of an array of
function pointers
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
void f() {
typedef void(*arr[T::value])();
new arr; // OK
new (void(*[(T::value)])()); // OK
new (void(*[T::value])()); // error: capture of non-variable 'T'
}
struct S {
static constexpr int value = 5;
};
int main() {
f();
}
/*** END SOURCE ***/
The last new-expression is rejected (as I believe, incorrectly). For
comparison, clang and MSVC compile this code successfully.
Tested with build 9.0.0 20180726 (experimental).
[Bug c++/86728] New: [Regression] unexpected error: conversion from ', ...)>' to non-scalar type 'std::function' requested
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86728
Bug ID: 86728
Summary: [Regression] unexpected error: conversion from
', ...)>' to non-scalar type
'std::function' requested
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/*** BEGIN SOURCE ***/
#include
std::function a = [](int x ...) { }; // OK
std::function b = [](auto x, ...) { }; // OK
std::function c = [](auto x ...) { }; /* error: conversion from
', ...)>' to non-scalar type 'std::function'
requested */
/ END SOURCE /
The error in the last line appears with build 9.0.0 20180728 (experimental),
8.2, 8.1. This code used to compile successfully with GCC versions 6.1 - 7.3.
For comparison, the latest versions of clang and MSVC compile this code
successfully as well.
[Bug c++/86883] New: Unexpected error: expansion pattern '' contains no argument packs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86883
Bug ID: 86883
Summary: Unexpected error: expansion pattern ''
contains no argument packs
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct A {
template class Head, T... Args>
static constexpr Head foo = { };
};
template
struct C {
static constexpr auto value = x;
};
using type = decltype(A::foo);
static_assert(type::value == 1);
/*** END SOURCE ***/
The g++ 8.2.0 compiler rejects this code:
/** BEGIN OUTPUT **/
:4:34: error: expansion pattern '' contains no argument
packs
static constexpr Head foo = { };
^
/*** END OUTPUT ***/
I believe the code is correct and should be compiled successfully. For
comparison, Clang accepts it.
[Bug c++/86915] New: Segmentation fault for an array of auto in template parameter
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86915 Bug ID: 86915 Summary: Segmentation fault for an array of auto in template parameter Product: gcc Version: 9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: v.reshetnikov at gmail dot com Target Milestone: --- /** BEGIN SOURCE **/ template struct S; /*** END SOURCE ***/ ' Segmentation fault 1 | template struct S; | ^ Tested with 9.0.0 20180809 (experimental)
[Bug c++/86918] New: internal compiler error: unexpected expression 'v' of kind template_parm_index
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86918
Bug ID: 86918
Summary: internal compiler error: unexpected expression 'v' of
kind template_parm_index
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct S {
template
struct X;
};
template<>
template
struct S::X {
static constexpr bool value = v;
};
static_assert(S::X::value);
/*** END SOURCE ***/
: In instantiation of 'struct S::X':
:13:30: required from here
:9:18: internal compiler error: unexpected expression 'v' of kind
template_parm_index
9 | struct S::X {
| ^
[Bug c++/86920] New: A matching template specialization is not selected
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86920
Bug ID: 86920
Summary: A matching template specialization is not selected
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct S {
template
struct X {
static constexpr bool value = false;
};
};
template<>
template
struct S::X {
static constexpr bool value = true;
};
static_assert(S::X::value);
/*** END SOURCE ***/
EXPECTED: no errors
ACTUAL:
:15:15: error: static assertion failed
15 | static_assert(S::X::value);
| ^~
[Bug c++/86926] New: [Regression] ICE for a recursive generic lambda
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86926
Bug ID: 86926
Summary: [Regression] ICE for a recursive generic lambda
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/* BEGIN SOURCE */
int main() {
constexpr auto f = [](auto self, auto n) {
if(n < 2) return n;
return self(self, n - 1) + self(self, n - 2);
};
constexpr auto fibonacci = [=](auto n) { return f(f, n); };
static_assert(fibonacci(7) == 13);
}
/** END SOURCE **/
Compile with -std=c++17.
EXPECTED: no errors.
ACTUAL:
: In instantiation of 'main():: [with auto:3 = int]':
:11:30: required from here
:9:54: internal compiler error: in build_over_call, at cp/call.c:8214
9 | constexpr auto fibonacci = [=](auto n) { return f(f, n); };
| ~^~
Tested with build 9.0.0 20180810 (experimental), appears to be a regression
from GCC 8.2. For comparison, the code also successfully compiles with Clang.
[Bug c++/86926] [Regression] ICE for a recursive generic lambda
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86926 --- Comment #1 from Vladimir Reshetnikov --- Note: the error disappears if the variable `f` is not declared `constexpr`.
[Bug c++/86956] New: Use of an alias template unexpectedly breaks compilation
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86956
Bug ID: 86956
Summary: Use of an alias template unexpectedly breaks
compilation
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct Outer {
template
struct Inner;
template
using Alias = Inner;
};
template<>
template
struct Outer::Inner {
static constexpr bool value = v;
};
static_assert(Outer::Inner::value); // OK
static_assert(Outer::Alias::value); // error
/*** END SOURCE ***/
The first static_assert compiles OK, but the second results in unexpected
errors:
/** BEGIN OUTPUT **/
: In instantiation of 'struct Outer::Inner':
:17:39: required from here
:12:27: error: type/value mismatch at argument 1 in template parameter
list for 'template > struct Outer::Inner< >'
12 | struct Outer::Inner {
| ^
:12:27: note: expected a constant of type 'bool', got 'void'
:12:27: error: type/value mismatch at argument 1 in template parameter
list for 'Outer::Inner< >::Inner'
:12:27: note: expected a constant of type 'bool', got 'void'
:13:27: error: type/value mismatch at argument 1 in template parameter
list for 'template > struct Outer::Inner< >'
13 | static constexpr bool value = v;
| ^
:13:27: note: expected a constant of type 'bool', got 'void'
:13:27: error: type/value mismatch at argument 1 in template parameter
list for 'value'
:13:27: note: expected a constant of type 'bool', got 'void'
:17:41: error: 'value' is not a member of 'Outer::Alias'
{aka 'Outer::Inner'}
17 | static_assert(Outer::Alias::value); // error
| ^
Compiler returned: 1
/*** END OUTPUT ***/
The part "expected a constant of type 'bool', got 'void'" looks inexplicable;
"Inner< >" is also difficult to decipher. The issue is discovered
with build 9.0.0 20180813 (experimental), but appears to exist in earlier
versions as well.
For comparison, Clang compiles this code successfully.
[Bug c++/86958] New: ICE in finish_member_declaration when an alias template is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86958
Bug ID: 86958
Summary: ICE in finish_member_declaration when an alias
template is used
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct Outer {
template
struct Inner;
template
using Alias = Inner;
};
template<>
template
struct Outer::Inner {
static constexpr bool value = v;
};
static_assert(Outer::Inner::value == sizeof(bool)); // OK
static_assert(Outer::Alias::value == sizeof(bool); // error
/*** END SOURCE ***/
The first static_assert compiles OK, but the second results in an ICE:
/** BEGIN OUTPUT **/
: In instantiation of 'struct Outer::Inner':
:17:39: required from here
:13:27: internal compiler error: in finish_member_declaration, at
cp/semantics.c:3085
13 | static constexpr auto value = sizeof(T);
| ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
/*** END OUTPUT ***/
This issue was found with build 9.0.0 20180813 (experimental), but appears to
exist in earlier versions as well.
For comparison, Clang compiles this code successfully.
[Bug c++/86958] ICE in finish_member_declaration when an alias template is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86958 --- Comment #1 from Vladimir Reshetnikov --- Sorry, there is a missing closing parenthesis in my code. The last line should look like this: static_assert(Outer::Alias::value == sizeof(bool)); // error
[Bug c++/86959] New: Use of a variadic alias template unexpectedly breaks compilation
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86959
Bug ID: 86959
Summary: Use of a variadic alias template unexpectedly breaks
compilation
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/*** BEGIN SOURCE ***/
template
struct Outer {
template
struct Inner;
template
using Alias = Inner;
};
template<>
template
struct Outer::Inner {
static constexpr auto value = sizeof...(T);
};
static_assert(Outer::Inner::value == 1); // OK
static_assert(Outer::Alias::value == 1); // error
/ END SOURCE /
The first static_assert compiles OK, but the second results in unexpected
errors:
/*** BEGIN OUTPUT ***/
: In instantiation of 'struct Outer::Inner':
:17:39: required from here
:12:27: error: template argument 1 is invalid
12 | struct Outer::Inner {
| ^
:12:27: error: template argument 1 is invalid
:13:27: error: template argument 1 is invalid
13 | static constexpr auto value = sizeof...(T);
| ^
:13:27: error: template argument 1 is invalid
:17:41: error: 'value' is not a member of 'Outer::Alias'
{aka 'Outer::Inner'}
17 | static_assert(Outer::Alias::value == 1); // error
| ^
Compiler returned: 1
/ END OUTPUT /
The issue was discovered with build 9.0.0 20180813 (experimental), but appears
to exist in earlier versions as well.
For comparison, Clang compiles this code successfully.
Might be related to Bug 86956 and Bug 86958.
[Bug c++/86918] internal compiler error: unexpected expression 'v' of kind template_parm_index
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86918
--- Comment #4 from Vladimir Reshetnikov ---
I could not find a wording in the Standard that disallows this kind of
specialization (although certainly I might have overlooked it). A similar code
where the template parameter list is changed in a specialization compiles
successfully with GCC:
template
struct Outer {
template
struct Inner;
};
template<>
template
struct Outer::Inner {
static constexpr auto value = sizeof...(x);
};
static_assert(Outer::Inner<>::value == 0); // OK
[Bug c++/86960] New: [Regression] internal compiler error: in coerce_template_parms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86960
Bug ID: 86960
Summary: [Regression] internal compiler error: in
coerce_template_parms
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct Outer {
template
struct Inner;
};
template<>
template
struct Outer::Inner {
static constexpr bool value = x;
};
static_assert(Outer::Inner::value); /* internal compiler error: in
coerce_template_parms, at cp/pt.c:8533 */
/*** END SOURCE ***/
Fails in GCC 8.1 and 8.2, compiles successfully with 7.3.
Might be related to Bug 86918, Bug 86920, Bug 86956, Bug 86958.
[Bug c++/86958] ICE in finish_member_declaration when an alias template is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86958 --- Comment #4 from Vladimir Reshetnikov --- Apparently, I somehow pasted a wrong code into this bug report. If you wish, you can close this one, and I will file proper one(s).
[Bug c++/86961] New: ICE in finish_member_declaration when an alias template is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86961
Bug ID: 86961
Summary: ICE in finish_member_declaration when an alias
template is used
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/** BEGIN SOURCE **/
template
struct Outer {
template
struct Inner;
template
using Alias = Inner;
};
template<>
template
struct Outer::Inner {
static constexpr auto value = sizeof(T);
};
static_assert(Outer::Inner::value == sizeof(bool)); // OK
static_assert(Outer::Alias::value == sizeof(bool)); // error
/*** END SOURCE ***/
The first static_assert compiles OK, but the second results in an ICE:
/** BEGIN OUTPUT **/
: In instantiation of 'struct Outer::Inner':
:17:39: required from here
:13:27: internal compiler error: in finish_member_declaration, at
cp/semantics.c:3085
13 | static constexpr auto value = sizeof(T);
| ^
Compiler returned: 1
/*** END OUTPUT ***/
This issue was found with build 9.0.0 20180813 (experimental), but appears to
exist in earlier versions as well.
For comparison, Clang compiles this code successfully.
[Bug c++/86958] ICE in finish_member_declaration when an alias template is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86958 Vladimir Reshetnikov changed: What|Removed |Added Status|RESOLVED|CLOSED --- Comment #6 from Vladimir Reshetnikov --- I filed a corrected version as Bug 86961.
[Bug c++/86915] Segmentation fault for an array of auto in template parameter
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86915 Vladimir Reshetnikov changed: What|Removed |Added Status|RESOLVED|VERIFIED --- Comment #4 from Vladimir Reshetnikov --- Verified.
[Bug c++/86728] [7/8/9 Regression] unexpected error: conversion from ', ...)>' to non-scalar type 'std::function' requested
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86728 Vladimir Reshetnikov changed: What|Removed |Added Status|RESOLVED|VERIFIED --- Comment #7 from Vladimir Reshetnikov --- Verified in 9.0.0 20180813 (experimental).
[Bug c++/84839] [6/7 Regression] ICE (Segmentation fault) when `decltype` is used with parameter pack
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84839 Vladimir Reshetnikov changed: What|Removed |Added Status|RESOLVED|VERIFIED --- Comment #5 from Vladimir Reshetnikov --- Verified.
[Bug c++/84798] [6/7 Regression] ICE (Segmentation fault) if `auto` appears in a template argument
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84798 Vladimir Reshetnikov changed: What|Removed |Added Status|RESOLVED|VERIFIED --- Comment #11 from Vladimir Reshetnikov --- Verified.
[Bug c++/84840] [6/7/8 Regression] ICE (in poplevel_class) for `auto` in alias declaration
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84840 Vladimir Reshetnikov changed: What|Removed |Added Status|RESOLVED|VERIFIED --- Comment #3 from Vladimir Reshetnikov --- Verified.
[Bug c++/86966] New: ICE (Segmentation fault) for an explicit specialization of a member class template
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86966
Bug ID: 86966
Summary: ICE (Segmentation fault) for an explicit
specialization of a member class template
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/* SOURCE */
template
struct S {
template
struct X { };
};
template<>
template<>
struct S<>::X { };
S<>::X<> x;
/*** END SOURCE ***/
/* OUTPUT */
:11:8: internal compiler error: Segmentation fault
11 | S<>::X<> x;
|^
Compiler returned: 1
/*** END OUTPUT ***/
[Bug c++/86966] ICE (Segmentation fault) for an explicit specialization of a member class template
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86966
--- Comment #2 from Vladimir Reshetnikov ---
I believe the code is valid. We explicitly specialize the member class template
X of S for S<> (i.e. the parameter pack T is empty). T is expanded into a list
of zero non-type template parameters of S<>::X.
Here is a similar code where we specialize for S, i.e. provide one
template argument bool for the pack T:
template
struct S {
template
struct X { };
};
template<>
template
struct S::X { };
Here T is expanded into a list of one non-type template parameter of type bool.
This code compiles successfully.
[Bug c++/86966] ICE (Segmentation fault) for an explicit specialization of a member class template
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86966 --- Comment #3 from Vladimir Reshetnikov --- Might be related to Bug 86960 and Bug 86918.
[Bug c++/86966] ICE (Segmentation fault) for an explicit specialization of a member class template
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86966 --- Comment #4 from Vladimir Reshetnikov --- Also, might be related to Bug 84796.
[Bug c++/86960] [Regression] internal compiler error: in coerce_template_parms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86960 --- Comment #2 from Vladimir Reshetnikov --- Also, might be related to Bug 84796 and Bug 86961.
[Bug c++/86961] ICE in finish_member_declaration when an alias template is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86961 --- Comment #1 from Vladimir Reshetnikov --- Might be related to Bug 86956 and Bug 86959.
[Bug c++/86969] New: [Regression] ICE (in tsubst_copy) for a generic recursive lambda
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86969
Bug ID: 86969
Summary: [Regression] ICE (in tsubst_copy) for a generic
recursive lambda
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/* BEGIN SOURCE */
auto compose = [](auto... fs) {
if constexpr (sizeof...(fs) == 0) {
return [](auto x) { return x; };
} else {
auto fn = [](auto self, auto f, auto... fs) {
if constexpr (sizeof...(fs) == 0) return f;
else return [=](auto x) {
return f(self(self, fs...)(x));
};
};
return fn(fn, fs...);
}
};
static_assert(compose(
[](auto x) { return x * 3; },
[](auto x) { return x + 1; },
[](auto x) { return x / 2; }
)(6) == 12);
/** END SOURCE **/
EXPECTED: no errors.
ACTUAL:
: In instantiation of ' [with auto:1 =
{, , }]:: [with auto:3 = [with auto:1 =
{, , }]::; auto:4 = ; auto:5 = {,
}]':
:11:18: required from ' [with auto:1 =
{, , }]'
:19:5: required from here
:8:30: internal compiler error: in tsubst_copy, at cp/pt.c:15348
8 | return f(self(self, fs...)(x));
| ^
Compiles successfully with 7.3, fails with 8.1 and newer. Compiles successfully
with Clang. Looks similar to Bug 86926, but ICE location is different.
[Bug c++/86986] New: Unexpected errors for template parameter pack in a template template parameter
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86986
Bug ID: 86986
Summary: Unexpected errors for template parameter pack in a
template template parameter
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/* SOURCE */
template
struct X {
template class...>
struct Y { };
};
using type = X::Y<>;
/*** END SOURCE ***/
/* OUTPUT */
: In instantiation of 'struct X':
:7:20: required from here
:4:12: error: '' is not a valid type for a
template non-type parameter
4 | struct Y { };
|^
:4:12: error: '' is not a valid type for a
template non-type parameter
:7:22: error: 'Y' in 'struct X' does not name a template type
7 | using type = X::Y<>;
| ^
Compiler returned: 1
/*** END OUTPUT ***/
Clang compiles this code successfully
[Bug c++/87001] New: False error "expansion pattern 'x' contains no argument packs"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87001
Bug ID: 87001
Summary: False error "expansion pattern 'x' contains no
argument packs"
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/*** BEGIN SOURCE ***/
template
struct X {
template class U>
struct Y {
template
using type = U;
};
};
/ END SOURCE /
Or, without using the `typeof` extension, it can be written:
/*** BEGIN SOURCE ***/
template
struct X {
template class U>
struct Y {
template
using type = U;
};
};
/ END SOURCE /
There is an unexpected error:
:6:28: error: expansion pattern 'x' contains no parameter packs
6 | using type = U;
|^
Compiler returned: 1
For comparison, it compiles fine with Clang.
[Bug c++/87012] New: [Regression] ICE in verify_unstripped_args_1
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87012
Bug ID: 87012
Summary: [Regression] ICE in verify_unstripped_args_1
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/* BEGIN SOURCE */
template
using ref = T&;
int x;
template class T, T>
struct X { };
struct Y : X { };
/** END SOURCE **/
: In instantiation of 'struct X':
:9:12: required from here
:7:10: internal compiler error: in verify_unstripped_args_1, at
cp/pt.c:1155
7 | struct X { };
| ^
Compiler returned: 1
Compiles fine with GCC 8.2 and Clang.
[Bug c++/84796] New: ICE in a template parameter pack expansion
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84796
Bug ID: 84796
Summary: ICE in a template parameter pack expansion
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
The following C++ code causes an ICE in GCC 8.0.1 20180308 (tested with
https://godbolt.org/):
/* SOURCE */
template
struct S {
template
static void f() { }
};
int main(){
S::f<0>();
}
/*** END SOURCE ***/
/* OUTPUT */
: In function 'int main()':
:8:18: internal compiler error: tree check: accessed elt 1 of tree_vec
with 0 elts in tsubst_pack_expansion, at cp/pt.c:11743
S::f<0>();
^
mmap: Invalid argument
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
/*** END OUTPUT ***/
Looks like a regression: no ICE occurs with GCC 7.3, but the code is rejected
with an error (I believe, incorrectly):
/* OUTPUT */
: In function 'int main()':
:8:18: error: no matching function for call to 'S::f<0>()'
S::f<0>();
^
:4:17: note: candidate: template static void S::f() [with T
...n = {n ...}; T = {int}]
static void f() { }
^
:4:17: note: template argument deduction/substitution failed:
Compiler returned: 1
/*** END OUTPUT ***/
[Bug c++/84798] New: ICE (Segmentation fault) if `auto` appears in a template argument
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84798
Bug ID: 84798
Summary: ICE (Segmentation fault) if `auto` appears in a
template argument
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
The following C++ code causes an ICE in GCC 8.0.1 20180308 (tested with
https://godbolt.org/):
/** SOURCE **/
template
struct S {
static constexpr T value = 0;
};
constexpr auto x = S::value;
/ END SOURCE /
/** OUTPUT **/
:6:38: internal compiler error: Segmentation fault
constexpr auto x = S::value;
^
mmap: Invalid argument
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
/ END OUTPUT /
The same problem appears to exist in all versions since GCC 6.1.
[Bug c++/84839] New: ICE (Segmentation fault) when `decltype` is used with parameter pack
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84839
Bug ID: 84839
Summary: ICE (Segmentation fault) when `decltype` is used with
parameter pack
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
The following C++ code causes an ICE in GCC 8.0.1 20180312 (tested with
https://godbolt.org/):
/* SOURCE */
template
struct S {
using fptr = void(*)(T... x, decltype(x)... y);
};
using F = S::fptr;
/*** END SOURCE ***/
/* OUTPUT */
g++: internal compiler error: Segmentation fault signal terminated program
cc1plus
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 4
/*** END OUTPUT ***/
[Bug c++/84840] New: ICE (in poplevel_class) for `auto` in alias declaration
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84840
Bug ID: 84840
Summary: ICE (in poplevel_class) for `auto` in alias
declaration
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
The following C++ code causes an ICE in GCC 8.0.1 20180312 (tested with
https://godbolt.org/):
/* SOURCE */
struct S {
using type = void(auto);
};
/*** END SOURCE ***/
/* OUTPUT */
:3:1: internal compiler error: in poplevel_class, at
cp/name-lookup.c:4423
};
^
mmap: Invalid argument
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
/*** END OUTPUT ***/
[Bug c++/84857] New: A valid call to a template function in a variadic template struct is rejected
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84857
Bug ID: 84857
Summary: A valid call to a template function in a variadic
template struct is rejected
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
The following C++ code is rejected by GCC 8.0.1 20180313 (tested with
https://godbolt.org/):
/* SOURCE */
template
struct S {
template
static int f() {
return 0;
}
};
int t = S::f<0, 0>();
/*** END SOURCE ***/
/* OUTPUT */
:9:30: error: no matching function for call to 'S::f<0, 0>()'
int t = S::f<0, 0>();
^
:4:16: note: candidate: 'template static int S::f() [with T
...xs = {xs ...}; T = {int, int}]'
static int f() {
^
:4:16: note: template argument deduction/substitution failed:
:9:30: error: wrong number of template arguments (2, should be 1)
int t = S::f<0, 0>();
^
Compiler returned: 1
/*** END OUTPUT ***/
I believe this code is correct and should be accepted.
[Bug c++/84893] New: Rejects a valid code with variadic function template taking a function pointer
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84893
Bug ID: 84893
Summary: Rejects a valid code with variadic function template
taking a function pointer
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
The following C++ code is rejected by GCC 8.0.1 20180313 (tested with
https://godbolt.org/):
/* SOURCE */
template
void f(void(*)(T..., int)) { }
void g(bool, int) { }
int main() {
f(g);
}
/*** END SOURCE ***/
/* OUTPUT */
: In function 'int main()':
:7:14: error: no matching function for call to 'f(void (&)(bool,
int))'
f(g);
^
:2:6: note: candidate: 'template void f(void (*)(T ...,
int))'
void f(void(*)(T..., int)) { }
^
:2:6: note: template argument deduction/substitution failed:
:7:14: note: mismatched types 'int' and 'bool'
f(g);
^
Compiler returned: 1
/*** END OUTPUT ***/
I believe the code is valid and should be compiled successfully.
