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Check all opaque types, even return position impl trait.

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While not necessary right now, this is the safe choice and will
be necessary for lazy TAIT.
This commit is contained in:
Oli Scherer 2021-12-01 16:34:40 +00:00
parent 5d07a6ceb4
commit 15f7e818ec
1 changed files with 18 additions and 14 deletions
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32
compiler/rustc_typeck/src/check/check.rs
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@ -626,7 +626,7 @@ pub(super) fn check_opaque_for_cycles<'tcx>(
///
/// Without this check the above code is incorrectly accepted: we would ICE if
/// some tried, for example, to clone an `Option<X<&mut ()>>`.
#[instrument(skip(tcx))]
#[instrument(level = "debug", skip(tcx))]
fn check_opaque_meets_bounds<'tcx>(
tcx: TyCtxt<'tcx>,
def_id: LocalDefId,
@ -634,17 +634,14 @@ fn check_opaque_meets_bounds<'tcx>(
span: Span,
origin: &hir::OpaqueTyOrigin,
) {
match origin {
// Checked when type checking the function containing them.
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => return,
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias => {}
}
let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
let param_env = tcx.param_env(def_id);
let defining_use_anchor = match *origin {
hir::OpaqueTyOrigin::FnReturn(did) | hir::OpaqueTyOrigin::AsyncFn(did) => did,
hir::OpaqueTyOrigin::TyAlias => def_id,
};
let param_env = tcx.param_env(defining_use_anchor);
tcx.infer_ctxt().with_opaque_type_inference(def_id).enter(move |infcx| {
tcx.infer_ctxt().with_opaque_type_inference(defining_use_anchor).enter(move |infcx| {
let inh = Inherited::new(infcx, def_id);
let infcx = &inh.infcx;
let opaque_ty = tcx.mk_opaque(def_id.to_def_id(), substs);
@ -678,10 +675,17 @@ fn check_opaque_meets_bounds<'tcx>(
infcx.report_fulfillment_errors(&errors, None, false);
}
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
let fcx = FnCtxt::new(&inh, param_env, hir_id);
fcx.regionck_item(hir_id, span, FxHashSet::default());
match origin {
// Checked when type checking the function containing them.
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => return,
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias => {
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
let fcx = FnCtxt::new(&inh, param_env, hir_id);
fcx.regionck_item(hir_id, span, FxHashSet::default());
}
}
});
}