bjoernager/rust
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wf-check RPITs

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This commit is contained in:
lcnr 2024-02-27 15:00:22 +01:00
parent 91cae1dcdc
commit 93bc7a428c
10 changed files with 184 additions and 34 deletions
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39
compiler/rustc_hir_analysis/src/check/check.rs
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@ -403,16 +403,6 @@ fn check_opaque_meets_bounds<'tcx>(
return Err(guar);
}
match origin {
// Checked when type checking the function containing them.
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => {
// HACK: this should also fall through to the hidden type check below, but the original
// implementation had a bug where equivalent lifetimes are not identical. This caused us
// to reject existing stable code that is otherwise completely fine. The real fix is to
// compare the hidden types via our type equivalence/relation infra instead of doing an
// identity check.
let _ = infcx.take_opaque_types();
return Ok(());
}
// Nested opaque types occur only in associated types:
// ` type Opaque<T> = impl Trait<&'static T, AssocTy = impl Nested>; `
// They can only be referenced as `<Opaque<T> as Trait<&'static T>>::AssocTy`.
@ -421,20 +411,33 @@ fn check_opaque_meets_bounds<'tcx>(
hir::OpaqueTyOrigin::TyAlias { .. }
if tcx.def_kind(tcx.parent(def_id.to_def_id())) == DefKind::OpaqueTy => {}
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias { .. } => {
let wf_tys = ocx.assumed_wf_types_and_report_errors(param_env, def_id)?;
hir::OpaqueTyOrigin::TyAlias { .. }
| hir::OpaqueTyOrigin::FnReturn(..)
| hir::OpaqueTyOrigin::AsyncFn(..) => {
let wf_tys = ocx.assumed_wf_types_and_report_errors(param_env, defining_use_anchor)?;
let implied_bounds = infcx.implied_bounds_tys(param_env, def_id, &wf_tys);
let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
ocx.resolve_regions_and_report_errors(defining_use_anchor, &outlives_env)?;
}
}
// Check that any hidden types found during wf checking match the hidden types that `type_of` sees.
for (mut key, mut ty) in infcx.take_opaque_types() {
ty.hidden_type.ty = infcx.resolve_vars_if_possible(ty.hidden_type.ty);
key = infcx.resolve_vars_if_possible(key);
sanity_check_found_hidden_type(tcx, key, ty.hidden_type)?;
if let hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) = origin {
// HACK: this should also fall through to the hidden type check below, but the original
// implementation had a bug where equivalent lifetimes are not identical. This caused us
// to reject existing stable code that is otherwise completely fine. The real fix is to
// compare the hidden types via our type equivalence/relation infra instead of doing an
// identity check.
let _ = infcx.take_opaque_types();
Ok(())
} else {
// Check that any hidden types found during wf checking match the hidden types that `type_of` sees.
for (mut key, mut ty) in infcx.take_opaque_types() {
ty.hidden_type.ty = infcx.resolve_vars_if_possible(ty.hidden_type.ty);
key = infcx.resolve_vars_if_possible(key);
sanity_check_found_hidden_type(tcx, key, ty.hidden_type)?;
}
Ok(())
}
Ok(())
}
fn sanity_check_found_hidden_type<'tcx>(