blob: f28b0f499f082fe9ba3920c2121c80c5eb14bf72 (
plain)
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
|
use crate::ty::{self, AdtSizedConstraint, Ty, TyCtxt, TyS};
pub(super) trait Value<'tcx>: Sized {
fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self;
}
impl<'tcx, T> Value<'tcx> for T {
default fn from_cycle_error(tcx: TyCtxt<'tcx>) -> T {
tcx.sess.abort_if_errors();
bug!("Value::from_cycle_error called without errors");
}
}
impl<'tcx> Value<'tcx> for &'_ TyS<'_> {
fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
// SAFETY: This is never called when `Self` is not `Ty<'tcx>`.
// FIXME: Represent the above fact in the trait system somehow.
unsafe { std::mem::transmute::<Ty<'tcx>, Ty<'_>>(tcx.ty_error()) }
}
}
impl<'tcx> Value<'tcx> for ty::SymbolName<'_> {
fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
// SAFETY: This is never called when `Self` is not `SymbolName<'tcx>`.
// FIXME: Represent the above fact in the trait system somehow.
unsafe {
std::mem::transmute::<ty::SymbolName<'tcx>, ty::SymbolName<'_>>(ty::SymbolName::new(
tcx, "<error>",
))
}
}
}
impl<'tcx> Value<'tcx> for AdtSizedConstraint<'_> {
fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
// SAFETY: This is never called when `Self` is not `AdtSizedConstraint<'tcx>`.
// FIXME: Represent the above fact in the trait system somehow.
unsafe {
std::mem::transmute::<AdtSizedConstraint<'tcx>, AdtSizedConstraint<'_>>(
AdtSizedConstraint(tcx.intern_type_list(&[tcx.ty_error()])),
)
}
}
}
|
