https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88520
Bug ID: 88520
Summary: improve warning when `struct` is required
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: tromey at gcc dot gnu.org
Target Milestone: ---
Consider this source:
int Foo;
struct Foo
{
int a;
};
extern int f(Foo x);
gcc (I'm using 8.2.1 from Fedora 28) says:
q.cc:8:14: warning: ‘f’ initialized and declared ‘extern’
extern int f(Foo x);
^~~
q.cc:8:17: error: expected ‘)’ before ‘x’
extern int f(Foo x);
~ ^~
)
clang is somewhat nicer here, showing where the definition appeared.
This is handy info for figuring out what went wrong:
q.cc:8:14: error: must use 'struct' tag to refer to type 'Foo' in this scope
extern int f(Foo x);
^
struct
q.cc:1:5: note: struct 'Foo' is hidden by a non-type declaration of 'Foo' here
int Foo;
^
This came up on the gdb list, where a user couldn't figure out why
gcc was erroring.
