bjoernager/rust
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Implement negative bounds

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This commit is contained in:
Michael Goulet 2023-04-25 05:15:50 +00:00
parent 98c33e47a4
commit 6e01e910cb
33 changed files with 363 additions and 188 deletions
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17
compiler/rustc_ast_lowering/src/lib.rs
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@ -1368,13 +1368,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
this.arena.alloc_from_iter(bounds.iter().filter_map(|bound| match bound {
GenericBound::Trait(
ty,
TraitBoundModifier::None | TraitBoundModifier::MaybeConst,
TraitBoundModifier::None
| TraitBoundModifier::MaybeConst
| TraitBoundModifier::Negative,
) => Some(this.lower_poly_trait_ref(ty, itctx)),
// `~const ?Bound` will cause an error during AST validation
// anyways, so treat it like `?Bound` as compilation proceeds.
GenericBound::Trait(
_,
TraitBoundModifier::Maybe | TraitBoundModifier::MaybeConstMaybe,
TraitBoundModifier::Maybe
| TraitBoundModifier::MaybeConstMaybe
| TraitBoundModifier::MaybeConstNegative,
) => None,
GenericBound::Outlives(lifetime) => {
if lifetime_bound.is_none() {
@ -2421,11 +2425,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
TraitBoundModifier::None => hir::TraitBoundModifier::None,
TraitBoundModifier::MaybeConst => hir::TraitBoundModifier::MaybeConst,
TraitBoundModifier::Negative => {
if self.tcx.features().negative_bounds {
hir::TraitBoundModifier::Negative
} else {
hir::TraitBoundModifier::None
}
}
// `MaybeConstMaybe` will cause an error during AST validation, but we need to pick a
// placeholder for compilation to proceed.
TraitBoundModifier::MaybeConstMaybe | TraitBoundModifier::Maybe => {
hir::TraitBoundModifier::Maybe
}
TraitBoundModifier::MaybeConstNegative => hir::TraitBoundModifier::MaybeConst,
}
}