1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
use middle::ty::{self, Ty};
use middle::ty_relate::{self, Relate, TypeRelation, RelateResult};
use util::ppaux::Repr;
pub struct Match<'a, 'tcx: 'a> {
tcx: &'a ty::ctxt<'tcx>
}
impl<'a, 'tcx> Match<'a, 'tcx> {
pub fn new(tcx: &'a ty::ctxt<'tcx>) -> Match<'a, 'tcx> {
Match { tcx: tcx }
}
}
impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Match<'a, 'tcx> {
fn tag(&self) -> &'static str { "Match" }
fn tcx(&self) -> &'a ty::ctxt<'tcx> { self.tcx }
fn a_is_expected(&self) -> bool { true }
fn relate_with_variance<T:Relate<'a,'tcx>>(&mut self,
_: ty::Variance,
a: &T,
b: &T)
-> RelateResult<'tcx, T>
{
self.relate(a, b)
}
fn regions(&mut self, a: ty::Region, b: ty::Region) -> RelateResult<'tcx, ty::Region> {
debug!("{}.regions({}, {})",
self.tag(),
a.repr(self.tcx()),
b.repr(self.tcx()));
Ok(a)
}
fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
debug!("{}.tys({}, {})", self.tag(),
a.repr(self.tcx()), b.repr(self.tcx()));
if a == b { return Ok(a); }
match (&a.sty, &b.sty) {
(_, &ty::ty_infer(ty::FreshTy(_))) |
(_, &ty::ty_infer(ty::FreshIntTy(_))) => {
Ok(a)
}
(&ty::ty_infer(_), _) |
(_, &ty::ty_infer(_)) => {
Err(ty::terr_sorts(ty_relate::expected_found(self, &a, &b)))
}
(&ty::ty_err, _) | (_, &ty::ty_err) => {
Ok(self.tcx().types.err)
}
_ => {
ty_relate::super_relate_tys(self, a, b)
}
}
}
fn binders<T>(&mut self, a: &ty::Binder<T>, b: &ty::Binder<T>)
-> RelateResult<'tcx, ty::Binder<T>>
where T: Relate<'a,'tcx>
{
Ok(ty::Binder(try!(self.relate(a.skip_binder(), b.skip_binder()))))
}
}