https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107495
Bug ID: 107495
Summary: GCC does not consider the right contextual implicit
conversions
Product: gcc
Version: 12.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dangelog at gmail dot com
Target Milestone: ---
Testcase:
struct Test {
operator int *() const;
operator void *() const;
};
int main() {
Test t;
delete t;
}
GCC rejects this:
<source>: In function 'int main()':
<source>:32:12: error: ambiguous default type conversion from 'Test'
32 | delete t;
| ^
<source>:32:12: note: candidate conversions include 'Test::operator void*()
const' and 'Test::operator int*() const'
<source>:32:12: error: type 'struct Test' argument given to 'delete', expected
pointer
But this is wrong. https://eel.is/c++draft/expr.delete#1.sentence-5 says "If of
class type, the operand is contextually implicitly converted to a pointer to
object type" and the attached note explicitly says "This implies that an object
cannot be deleted using a pointer of type void* because void is not an object
type".
The definition of contextual conversion says
https://eel.is/c++draft/conv#general-5 :
"C is searched for non-explicit conversion functions whose return type is cv T
or reference to cv T such that T is allowed by the context. There shall be
exactly one such T."
There is exactly one such T (conversion to pointer of object type), so GCC is
rejecting valid code.
