bjoernager/rust
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Do not call object_lifetime_default on lifetime params.

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This commit is contained in:
Camille GILLOT 2022-08-30 22:47:58 +02:00
parent ae0030beb0
commit e7164267a2
6 changed files with 115 additions and 78 deletions
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38
compiler/rustc_resolve/src/late/lifetimes.rs
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@ -1148,21 +1148,18 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
}
}
fn object_lifetime_default<'tcx>(
tcx: TyCtxt<'tcx>,
param_def_id: DefId,
) -> Option<ObjectLifetimeDefault> {
fn object_lifetime_default<'tcx>(tcx: TyCtxt<'tcx>, param_def_id: DefId) -> ObjectLifetimeDefault {
debug_assert_eq!(tcx.def_kind(param_def_id), DefKind::TyParam);
let param_def_id = param_def_id.expect_local();
let parent_def_id = tcx.local_parent(param_def_id);
let generics = tcx.hir().get_generics(parent_def_id)?;
let generics = tcx.hir().get_generics(parent_def_id).unwrap();
let param_hir_id = tcx.local_def_id_to_hir_id(param_def_id);
let param = generics.params.iter().find(|p| p.hir_id == param_hir_id)?;
let param = generics.params.iter().find(|p| p.hir_id == param_hir_id).unwrap();
// Scan the bounds and where-clauses on parameters to extract bounds
// of the form `T:'a` so as to determine the `ObjectLifetimeDefault`
// for each type parameter.
match param.kind {
GenericParamKind::Lifetime { .. } => None,
GenericParamKind::Type { .. } => {
let mut set = Set1::Empty;
@ -1181,21 +1178,17 @@ fn object_lifetime_default<'tcx>(
}
}
Some(match set {
match set {
Set1::Empty => ObjectLifetimeDefault::Empty,
Set1::One(hir::LifetimeName::Static) => ObjectLifetimeDefault::Static,
Set1::One(hir::LifetimeName::Param(param_def_id, _)) => {
ObjectLifetimeDefault::Param(param_def_id.to_def_id())
}
_ => ObjectLifetimeDefault::Ambiguous,
})
}
}
GenericParamKind::Const { .. } => {
// Generic consts don't impose any constraints.
//
// We still store a dummy value here to allow generic parameters
// in an arbitrary order.
Some(ObjectLifetimeDefault::Empty)
_ => {
bug!("object_lifetime_default_raw must only be called on a type parameter")
}
}
}
@ -1512,7 +1505,20 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
generics
.params
.iter()
.filter_map(|param| self.tcx.object_lifetime_default(param.def_id))
.filter_map(|param| {
match self.tcx.def_kind(param.def_id) {
// Generic consts don't impose any constraints.
//
// We still store a dummy value here to allow generic parameters
// in an arbitrary order.
DefKind::ConstParam => Some(ObjectLifetimeDefault::Empty),
DefKind::TyParam => Some(self.tcx.object_lifetime_default(param.def_id)),
// We may also get a `Trait` or `TraitAlias` because of how generics `Self` parameter
// works. Ignore it because it can't have a meaningful lifetime default.
DefKind::LifetimeParam | DefKind::Trait | DefKind::TraitAlias => None,
dk => bug!("unexpected def_kind {:?}", dk),
}
})
.map(set_to_region)
.collect()
});