https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121880
Bug ID: 121880
Summary: incorrect "deallocation of storage that was not
previously allocated" error message
Product: gcc
Version: 15.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: geza.herman at gmail dot com
Target Milestone: ---
I have a program which I think should compile, but it doesn't:
---- 8< -----
#include <memory>
struct Base {
void (*free_ptr)(Base *);
consteval Base();
consteval void free();
};
struct A: Base {
};
consteval void free_impl(Base *self_base) {
std::allocator<A>().deallocate(static_cast<A *>(self_base), 1);
}
consteval Base::Base() : free_ptr(free_impl) {
}
consteval void Base::free() {
free_ptr(this);
}
consteval void foo() {
A *a = std::allocator<A>().allocate(1);
a = new(a) A;
a->free();
// a->free_ptr(a);
}
int main() {
foo();
}
---- 8< -----
The program allocates and deallocates in a consteval function. GCC complains:
t.cpp: In function ‘int main()’:
t.cpp:32:8: error: call to consteval function ‘foo()’ is not a constant
expression
32 | foo();
| ~~~^~
In file included from /usr/include/c++/15/memory:67,
from t.cpp:1:
t.cpp:32:8: in ‘constexpr’ expansion of ‘foo()’
t.cpp:27:12: in ‘constexpr’ expansion of ‘a->A::Base.Base::free()’
t.cpp:21:13: in ‘constexpr’ expansion of
‘((Base*)this)->Base::free_ptr(((Base*)this))’
t.cpp:14:35: in ‘constexpr’ expansion of
‘std::allocator<A>().std::allocator<A>::deallocate(((A*)self_base), 1)’
/usr/include/c++/15/bits/allocator.h:212:30: error: deallocation of storage
that was not previously allocated
212 | ::operator delete(__p);
Interestingly, if instead of "a->free();", I use "a->free_ptr(a);", GCC
compiles the program.
This happens on GCC 16.0 as well.
