package main
func main() {
var x interface {} = 42;
switch x := x.(type) {
case int:
case foo:
}
}
before:
x.go:7: non-type case in type switch
x.go:7: inappropriate case for a type switch
now:
x.go:7: foo: undefined
R=ken
OCL=31221
CL=31221
this is not a user-visible change.
before, all interface values were
struct Itype {
Sigt *type;
Sigi *inter;
void *method[n];
}
struct Iface {
void *addr;
Itype *itype;
}
the itype is basically a vtable, but it's unnecessary
if the static type is interface{ }.
for interface values with static type empty, the
new representation is
struct Eface {
void *addr;
Sigt *type;
}
this complicates the code somewhat, but
it reduces the number of Itypes that
have to be computed and cached,
it opens up opportunities to avoid function
calls in a few common cases,
and it will make it possible to lay out
interface{} values at compile time,
which i think i'll need for the new reflection.
R=ken
OCL=28701
CL=29121