https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85004
Bug ID: 85004
Summary: ambiguous diagnostic: passing ‘const S’ as ‘this’
argument discards qualifiers
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
When invoking a non-const member function from a const one, GCC issues an error
message like those below. The error message is ambiguous: it doesn't make is
clear which this it refers to. In the first case, underling the first "this"
would help. In the second case rephrasing the error to say something like
"passing ‘const S’ as the implicit ‘this’ argument discards qualifiers" would
help avoid the confusion.
$ cat u.C && gcc -S -Wall u.C
struct S {
void f (const S*);
void g () const
{
this->f (this); // which 'this?'
f (this); // ditto
}
};
u.C: In member function ‘void S::g() const’:
u.C:6:18: error: passing ‘const S’ as ‘this’ argument discards qualifiers
[-fpermissive]
this->f (this); // which 'this?'
^
u.C:2:8: note: in call to ‘void S::f(const S*)’
void f (const S*);
^
u.C:8:12: error: passing ‘const S’ as ‘this’ argument discards qualifiers
[-fpermissive]
f (this); // ditto
^
u.C:2:8: note: in call to ‘void S::f(const S*)’
void f (const S*);
^
