bjoernager/rust
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Improve error message for opaque captures

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This commit is contained in:
Michael Goulet 2024-03-07 15:44:07 +00:00
parent 74acabe9b0
commit ffd30e0a69
25 changed files with 150 additions and 116 deletions
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68
compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
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@ -8,7 +8,6 @@
use rustc_ast::visit::walk_list;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_errors::{codes::*, struct_span_code_err};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::LocalDefId;
@ -673,34 +672,47 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
// and ban them. Type variables instantiated inside binders aren't
// well-supported at the moment, so this doesn't work.
// In the future, this should be fixed and this error should be removed.
let def = self.map.defs.get(&lifetime.hir_id).cloned();
let Some(ResolvedArg::LateBound(_, _, def_id)) = def else { continue };
let Some(def_id) = def_id.as_local() else { continue };
let hir_id = self.tcx.local_def_id_to_hir_id(def_id);
// Ensure that the parent of the def is an item, not HRTB
let parent_id = self.tcx.parent_hir_id(hir_id);
if !parent_id.is_owner() {
struct_span_code_err!(
self.tcx.dcx(),
lifetime.ident.span,
E0657,
"`impl Trait` can only capture lifetimes bound at the fn or impl level"
)
.emit();
self.uninsert_lifetime_on_error(lifetime, def.unwrap());
}
if let hir::Node::Item(hir::Item {
kind: hir::ItemKind::OpaqueTy { .. }, ..
}) = self.tcx.hir_node(parent_id)
let def = self.map.defs.get(&lifetime.hir_id).copied();
let Some(ResolvedArg::LateBound(_, _, lifetime_def_id)) = def else { continue };
let Some(lifetime_def_id) = lifetime_def_id.as_local() else { continue };
let lifetime_hir_id = self.tcx.local_def_id_to_hir_id(lifetime_def_id);
let bad_place = match self.tcx.hir_node(self.tcx.parent_hir_id(lifetime_hir_id))
{
self.tcx.dcx().struct_span_err(
lifetime.ident.span,
"higher kinded lifetime bounds on nested opaque types are not supported yet",
)
.with_span_note(self.tcx.def_span(def_id), "lifetime declared here")
.emit();
self.uninsert_lifetime_on_error(lifetime, def.unwrap());
}
// Opaques do not declare their own lifetimes, so if a lifetime comes from an opaque
// it must be a reified late-bound lifetime from a trait goal.
hir::Node::Item(hir::Item {
kind: hir::ItemKind::OpaqueTy { .. }, ..
}) => "higher-ranked lifetime from outer `impl Trait`",
// Other items are fine.
hir::Node::Item(_) | hir::Node::TraitItem(_) | hir::Node::ImplItem(_) => {
continue;
}
hir::Node::Ty(hir::Ty { kind: hir::TyKind::BareFn(_), .. }) => {
"higher-ranked lifetime from function pointer"
}
hir::Node::Ty(hir::Ty { kind: hir::TyKind::TraitObject(..), .. }) => {
"higher-ranked lifetime from `dyn` type"
}
_ => "higher-ranked lifetime",
};
let (span, label) = if lifetime.ident.span == self.tcx.def_span(lifetime_def_id)
{
let opaque_span = self.tcx.def_span(item_id.owner_id);
(opaque_span, Some(opaque_span))
} else {
(lifetime.ident.span, None)
};
// Ensure that the parent of the def is an item, not HRTB
self.tcx.dcx().emit_err(errors::OpaqueCapturesHigherRankedLifetime {
span,
label,
decl_span: self.tcx.def_span(lifetime_def_id),
bad_place,
});
self.uninsert_lifetime_on_error(lifetime, def.unwrap());
}
}
_ => intravisit::walk_ty(self, ty),