Check that the types in RPITITs are WF

This commit is contained in:
Michael Goulet 2022-09-11 06:58:11 +00:00
parent 98f3001eec
commit fd2766e7fd
3 changed files with 93 additions and 0 deletions

View file

@ -1,4 +1,5 @@
use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter};
use hir::def::DefKind;
use rustc_ast as ast;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
@ -1530,6 +1531,49 @@ fn check_fn_or_method<'tcx>(
);
check_where_clauses(wfcx, span, def_id);
check_return_position_impl_trait_in_trait_bounds(
tcx,
wfcx,
def_id,
sig.output(),
hir_decl.output.span(),
);
}
/// Basically `check_associated_type_bounds`, but separated for now and should be
/// deduplicated when RPITITs get lowered into real associated items.
fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
tcx: TyCtxt<'tcx>,
wfcx: &WfCheckingCtxt<'_, 'tcx>,
fn_def_id: LocalDefId,
fn_output: Ty<'tcx>,
span: Span,
) {
if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id())
&& assoc_item.container == ty::AssocItemContainer::TraitContainer
{
for arg in fn_output.walk() {
if let ty::GenericArgKind::Type(ty) = arg.unpack()
&& let ty::Projection(proj) = ty.kind()
&& tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
&& tcx.impl_trait_in_trait_parent(proj.item_def_id) == fn_def_id.to_def_id()
{
let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id);
let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| {
let normalized_bound = wfcx.normalize(span, None, bound);
traits::wf::predicate_obligations(
wfcx.infcx,
wfcx.param_env,
wfcx.body_id,
normalized_bound,
bound_span,
)
});
wfcx.register_obligations(wf_obligations);
}
}
}
}
const HELP_FOR_SELF_TYPE: &str = "consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, \