bjoernager/rust
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Replace tuple of infer vars for upvar_tys with single infer var

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This commit allows us to decide the number of captures required after
completing capture ananysis, which is required as part of implementing
RFC-2229.

Co-authored-by: Aman Arora <me@aman-arora.com>
Co-authored-by: Jenny Wills <wills.jenniferg@gmail.com>
This commit is contained in:
Roxane 2020-07-19 17:26:51 -04:00 • committed by Aman Arora
parent 25d2d09da7
commit dc183702da
23 changed files with 178 additions and 95 deletions
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34
compiler/rustc_trait_selection/src/traits/select/mod.rs
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@ -1631,7 +1631,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
ty::Closure(_, substs) => {
// (*) binder moved here
Where(ty::Binder::bind(substs.as_closure().upvar_tys().collect()))
let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = ty.kind() {
// Not yet resolved.
Ambiguous
} else {
Where(ty::Binder::bind(substs.as_closure().upvar_tys().collect()))
}
}
ty::Adt(..) | ty::Projection(..) | ty::Param(..) | ty::Opaque(..) => {
@ -1700,11 +1706,31 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
tys.iter().map(|k| k.expect_ty()).collect()
}
ty::Closure(_, ref substs) => substs.as_closure().upvar_tys().collect(),
ty::Closure(_, ref substs) => {
let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = ty.kind() {
// The inference variable will be replaced by a tuple once capture analysis
// completes. If the tuple meets a bound, so do all the elements within it.
vec![ty]
} else {
substs.as_closure().upvar_tys().collect()
}
}
ty::Generator(_, ref substs, _) => {
let witness = substs.as_generator().witness();
substs.as_generator().upvar_tys().chain(iter::once(witness)).collect()
let upvar_tys_resolved =
self.infcx.shallow_resolve(substs.as_generator().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = upvar_tys_resolved.kind() {
// The inference variable will be replaced by a tuple once capture analysis
// completes, if the tuple meets a bound, so do all the elements within it.
let witness_resolved =
self.infcx.shallow_resolve(substs.as_generator().witness());
vec![upvar_tys_resolved, witness_resolved]
} else {
let witness = substs.as_generator().witness();
substs.as_generator().upvar_tys().chain(iter::once(witness)).collect()
}
}
ty::GeneratorWitness(types) => {