https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101791
Bug ID: 101791
Summary: missing warning on a mismatch between scalar and array
forms of new and delete
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
The -Wmismatched-new-delete warning introduced in GCC 11 is meant to diagnose
calls to operator delete with pointers obtained from a mismatched form or
overload of operator new. A poster child for such a mismatch is the scalar
form of a delete expression with an argument obtained from array new. GCC 11
diagnoses such mismatches when they involve member operators new and delete (as
in g() below) but it fails to do the same for the default non-member operators
(as in h()).
$ cat t.C && gcc -S -Wall t.Ctypedef __SIZE_TYPE__ size_t;
struct A
{
void* operator new (size_t);
void operator delete (void*);
void* operator new[] (size_t);
void operator delete[] (void*);
};
void f (void*);
void g ()
{
A *p = new A[7];
f (p);
delete p; // -Wmismatched-new-delete (good)
}
void h ()
{
int *p = new int[7];
f (p);
delete p; // missing warning
}
t.C: In function ‘void g()’:
t.C:18:10: warning: ‘static void A::operator delete(void*)’ called on pointer
returned from a mismatched allocation function [-Wmismatched-new-delete]
18 | delete p; // -Wmismatched-new-delete (good)
| ^
t.C:16:17: note: returned from ‘static void* A::operator new [](size_t)’
16 | A *p = new A[7];
| ^
