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Don't require specifying unrelated assoc types when trait alias is in dyn type

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This commit is contained in:
Michael Goulet 2024-03-07 01:32:01 +00:00
parent 7d3702e472
commit 850cc34da2
4 changed files with 55 additions and 50 deletions
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80
compiler/rustc_hir_analysis/src/astconv/object_safety.rs
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@ -45,10 +45,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
dummy_self,
&mut bounds,
false,
// FIXME: This should be `true`, but we don't really handle
// associated type bounds or type aliases in objects in a way
// that makes this meaningful, I think.
OnlySelfBounds(false),
// True so we don't populate `bounds` with associated type bounds, even
// though they're disallowed from object types.
OnlySelfBounds(true),
) {
potential_assoc_types.extend(cur_potential_assoc_types);
}
@ -83,9 +82,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
let expanded_traits =
traits::expand_trait_aliases(tcx, trait_bounds.iter().map(|&(a, b)| (a, b)));
let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) = expanded_traits
.filter(|i| i.trait_ref().self_ty().skip_binder() == dummy_self)
.partition(|i| tcx.trait_is_auto(i.trait_ref().def_id()));
let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) =
expanded_traits.partition(|i| tcx.trait_is_auto(i.trait_ref().def_id()));
if regular_traits.len() > 1 {
let first_trait = &regular_traits[0];
let additional_trait = &regular_traits[1];
@ -158,7 +156,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
for (base_trait_ref, span) in regular_traits_refs_spans {
let base_pred: ty::Predicate<'tcx> = base_trait_ref.to_predicate(tcx);
for pred in traits::elaborate(tcx, [base_pred]) {
for pred in traits::elaborate(tcx, [base_pred]).filter_only_self() {
debug!("conv_object_ty_poly_trait_ref: observing object predicate `{:?}`", pred);
let bound_predicate = pred.kind();
@ -312,45 +310,39 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
})
});
let existential_projections = projection_bounds
.iter()
// We filter out traits that don't have `Self` as their self type above,
// we need to do the same for projections.
.filter(|(bound, _)| bound.skip_binder().self_ty() == dummy_self)
.map(|(bound, _)| {
bound.map_bound(|mut b| {
assert_eq!(b.projection_ty.self_ty(), dummy_self);
let existential_projections = projection_bounds.iter().map(|(bound, _)| {
bound.map_bound(|mut b| {
assert_eq!(b.projection_ty.self_ty(), dummy_self);
// Like for trait refs, verify that `dummy_self` did not leak inside default type
// parameters.
let references_self = b.projection_ty.args.iter().skip(1).any(|arg| {
if arg.walk().any(|arg| arg == dummy_self.into()) {
return true;
}
false
});
if references_self {
let guar = tcx.dcx().span_delayed_bug(
span,
"trait object projection bounds reference `Self`",
);
let args: Vec<_> = b
.projection_ty
.args
.iter()
.map(|arg| {
if arg.walk().any(|arg| arg == dummy_self.into()) {
return Ty::new_error(tcx, guar).into();
}
arg
})
.collect();
b.projection_ty.args = tcx.mk_args(&args);
// Like for trait refs, verify that `dummy_self` did not leak inside default type
// parameters.
let references_self = b.projection_ty.args.iter().skip(1).any(|arg| {
if arg.walk().any(|arg| arg == dummy_self.into()) {
return true;
}
false
});
if references_self {
let guar = tcx
.dcx()
.span_delayed_bug(span, "trait object projection bounds reference `Self`");
let args: Vec<_> = b
.projection_ty
.args
.iter()
.map(|arg| {
if arg.walk().any(|arg| arg == dummy_self.into()) {
return Ty::new_error(tcx, guar).into();
}
arg
})
.collect();
b.projection_ty.args = tcx.mk_args(&args);
}
ty::ExistentialProjection::erase_self_ty(tcx, b)
})
});
ty::ExistentialProjection::erase_self_ty(tcx, b)
})
});
let regular_trait_predicates = existential_trait_refs
.map(|trait_ref| trait_ref.map_bound(ty::ExistentialPredicate::Trait));