[Bug c/7654] warn if an enum is being assigned a non enum value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=7654
Eric Gallager changed:
What|Removed |Added
CC||egallager at gcc dot gnu.org
--- Comment #12 from Eric Gallager ---
(In reply to Martin Sebor from comment #11)
> I'll confirm this ancient request.
>
> Bug 78736 asks for something similar, and I'm working on enhancing the
> solution there even further (to diagnose assigning constants that don't have
> a corresponding enumerator in the destination type). I'll add that on the
> following slightly modified test case Clang issues the warnings below:
>
> $ cat t.C && clang -S -Wall -Wextra -Weverything -xc t.C
> void f (int i)
> {
> enum e1 { e1a, e1b };
> enum e1 e1v;
> enum e2 { e2a, e2b };
> enum e2 e2v;
>
> e1v = 1; // no warning
> e1v = 3; // warning
> e1v = e1a; // ok
> e2v = e1v; // warning
> i = e1v; // ok I guess
> e2v = i; // warning
> }
> t.C:9:9: warning: integer constant not in range of enumerated type 'enum e1'
> [-Wassign-enum]
> e1v = 3; // warning
> ^
> t.C:11:9: warning: implicit conversion from enumeration type 'enum e1' to
> different enumeration type 'enum e2' [-Wenum-conversion]
> e2v = e1v; // warning
> ~ ^~~
> t.C:13:9: warning: implicit conversion changes signedness: 'int' to 'enum e2'
> [-Wsign-conversion]
> e2v = i; // warning
> ~ ^
> t.C:1:6: warning: no previous prototype for function 'f'
> [-Wmissing-prototypes]
> void f (int i)
> ^
> 4 warnings
gcc now prints:
$ /usr/local/bin/gcc -c -S -Wall -Wextra -Wconversion -Wsign-conversion
-Wmissing-prototypes -pedantic -xc 7654.c
7654.c:1:6: warning: no previous prototype for 'f' [-Wmissing-prototypes]
1 | void f (int i)
| ^
7654.c: In function 'f':
7654.c:11:6: warning: implicit conversion from 'enum e1' to 'enum e2'
[-Wenum-conversion]
11 | e2v = e1v; // warning
| ^
7654.c:6:10: warning: variable 'e2v' set but not used
[-Wunused-but-set-variable]
6 | enum e2 e2v;
| ^~~
$
so, gcc has -Wenum-conversion now, but it is still missing warnings from
-Wassign-enum and -Wsign-conversion on this testcase.
[Bug c/7654] warn if an enum is being assigned a non enum value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=7654
Martin Sebor changed:
What|Removed |Added
Status|SUSPENDED |NEW
CC||msebor at gcc dot gnu.org
See Also||https://gcc.gnu.org/bugzill
||a/show_bug.cgi?id=78736
--- Comment #11 from Martin Sebor ---
I'll confirm this ancient request.
Bug 78736 asks for something similar, and I'm working on enhancing the solution
there even further (to diagnose assigning constants that don't have a
corresponding enumerator in the destination type). I'll add that on the
following slightly modified test case Clang issues the warnings below:
$ cat t.C && clang -S -Wall -Wextra -Weverything -xc t.C
void f (int i)
{
enum e1 { e1a, e1b };
enum e1 e1v;
enum e2 { e2a, e2b };
enum e2 e2v;
e1v = 1; // no warning
e1v = 3; // warning
e1v = e1a; // ok
e2v = e1v; // warning
i = e1v; // ok I guess
e2v = i; // warning
}
t.C:9:9: warning: integer constant not in range of enumerated type 'enum e1'
[-Wassign-enum]
e1v = 3; // warning
^
t.C:11:9: warning: implicit conversion from enumeration type 'enum e1' to
different enumeration type 'enum e2' [-Wenum-conversion]
e2v = e1v; // warning
~ ^~~
t.C:13:9: warning: implicit conversion changes signedness: 'int' to 'enum e2'
[-Wsign-conversion]
e2v = i; // warning
~ ^
t.C:1:6: warning: no previous prototype for function 'f' [-Wmissing-prototypes]
void f (int i)
^
4 warnings
[Bug c/7654] warn if an enum is being assigned a non enum value
--- Comment #10 from manu at gcc dot gnu dot org 2008-08-24 21:31 --- I think we should mark as SUSPENDED those enhancement requests where there is no consensus that we actually want the feature, even if a patch were available. It would be a waste of time to implement this just to have it rejected. -- manu at gcc dot gnu dot org changed: What|Removed |Added Status|NEW |SUSPENDED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=7654
[Bug c/7654] warn if an enum is being assigned a non enum value
--- Comment #9 from manu at gcc dot gnu dot org 2008-02-15 10:36 --- It is not clear whether we want such a warning or not (and in 6 years, just 2 people have suggested it not too loudly). But if we do: * -Wstrict-enums seems a better name. It should be consistent and not handle only assignments but also argument passing. * An explicit cast should suppress the warning. * The warning should not be enabled by -Wall and probably neither by -Wextra because enums are *correctly* used as integers by C programmers. It is also unclear whether we want to warn for any integer/enum assigned to a different enum type or just for integers/enums outside the range of a particular enum type. -- manu at gcc dot gnu dot org changed: What|Removed |Added Summary|-Wenum-assignment : Warn if |warn if an enum is being |an enum is being assigned a |assigned a non enum value |non enum value | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=7654
