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Add E0790 as more specific variant of E0283

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This commit is contained in:
aticu 2022-06-12 17:46:57 +02:00
parent 96c2df810b
commit 1cbacc0c8a
21 changed files with 354 additions and 92 deletions
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92
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
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@ -2104,6 +2104,98 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
);
}
}
if let (Some(body_id), Some(ty::subst::GenericArgKind::Type(_))) =
(body_id, subst.map(|subst| subst.unpack()))
{
struct FindExprBySpan<'hir> {
span: Span,
result: Option<&'hir hir::Expr<'hir>>,
}
impl<'v> hir::intravisit::Visitor<'v> for FindExprBySpan<'v> {
fn visit_expr(&mut self, ex: &'v hir::Expr<'v>) {
if self.span == ex.span {
self.result = Some(ex);
} else {
hir::intravisit::walk_expr(self, ex);
}
}
}
let mut expr_finder = FindExprBySpan { span, result: None };
expr_finder.visit_expr(&self.tcx.hir().body(body_id).value);
if let Some(hir::Expr {
kind: hir::ExprKind::Path(hir::QPath::Resolved(None, path)), .. }
) = expr_finder.result
&& let [
..,
trait_path_segment @ hir::PathSegment {
res: Some(rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id)),
..
},
hir::PathSegment {
ident: assoc_item_name,
res: Some(rustc_hir::def::Res::Def(_, item_id)),
..
}
] = path.segments
&& data.trait_ref.def_id == *trait_id
&& self.tcx.trait_of_item(item_id) == Some(*trait_id)
&& !self.is_tainted_by_errors()
{
let (verb, noun) = match self.tcx.associated_item(item_id).kind {
ty::AssocKind::Const => ("refer to the", "constant"),
ty::AssocKind::Fn => ("call", "function"),
ty::AssocKind::Type => ("refer to the", "type"), // this is already covered by E0223, but this single match arm doesn't hurt here
};
// Replace the more general E0283 with a more specific error
err.cancel();
err = self.tcx.sess.struct_span_err_with_code(
span,
&format!(
"cannot {verb} associated {noun} on trait without specifying the corresponding `impl` type",
),
rustc_errors::error_code!(E0790),
);
if let Some(local_def_id) = data.trait_ref.def_id.as_local()
&& let Some(hir::Node::Item(hir::Item { ident: trait_name, kind: hir::ItemKind::Trait(_, _, _, _, trait_item_refs), .. })) = self.tcx.hir().find_by_def_id(local_def_id)
&& let Some(method_ref) = trait_item_refs.iter().find(|item_ref| item_ref.ident == *assoc_item_name) {
err.span_label(method_ref.span, format!("`{}::{}` defined here", trait_name, assoc_item_name));
}
err.span_label(span, format!("cannot {verb} associated {noun} of trait"));
let trait_impls = self.tcx.trait_impls_of(data.trait_ref.def_id);
if trait_impls.blanket_impls().is_empty()
&& let Some((impl_ty, _)) = trait_impls.non_blanket_impls().iter().next()
&& let Some(impl_def_id) = impl_ty.def() {
let message = if trait_impls.non_blanket_impls().len() == 1 {
"use the fully-qualified path to the only available implementation".to_string()
} else {
format!(
"use a fully-qualified path to a specific available implementation ({} found)",
trait_impls.non_blanket_impls().len()
)
};
err.multipart_suggestion(
message,
vec![
(trait_path_segment.ident.span.shrink_to_lo(), format!("<{} as ", self.tcx.def_path(impl_def_id).to_string_no_crate_verbose())),
(trait_path_segment.ident.span.shrink_to_hi(), format!(">"))
],
Applicability::MaybeIncorrect
);
}
}
};
err
}