https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99526
Bug ID: 99526
Summary: Casts should retain typedef information
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: equinox-gccbugs at diac24 dot net
Target Milestone: ---
Currently, any cast in C will produce the "resolved" type regardless of whether
the cast is written using a typedef. E.g.:
typedef int i;
typedef const int cint;
typedef const i ci;
char v;
typeof((i)v) => int;
typeof((cint)v) => int;
typeof((ci)v) => int;
typeof((const i)v) => int;
The IMHO ideal situation would be:
typedef int i;
typedef const int cint;
typedef const i ci;
char v;
typeof((i)v) => i;
typeof((cint)v) => int;
typeof((ci)v) => i;
typeof((const i)v) => i;
Note that since casts produce rvalues, qualifiers need to be stripped, and thus
"ci" and "cint" shouldn't be used since the typedef itself contains a
qualifier.
My rationale for this is twofold:
- systems (on POSIX: pid_t, uid_t, gid_t, ...) have some types that are of
"unspecified" size, and it is helpful to be able to warn when these are
intermixed. Especially in printf() due to varargs calling: there is no format
specifier that is correct for these types.
- plugins may want to attach additional semantics to some typedefs, and this
breaks if the plugin can't get at the typedef.
