use rustc_middle::ty::abstract_const::NotConstEvaluatable;
use rustc_middle::ty::error::ExpectedFound;
use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
-use rustc_middle::ty::print::{FmtPrinter, Print};
+use rustc_middle::ty::print::{with_forced_trimmed_paths, FmtPrinter, Print};
use rustc_middle::ty::{
self, SubtypePredicate, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeFoldable,
TypeVisitable,
&& self.fallback_has_occurred
{
let predicate = trait_predicate.map_bound(|trait_pred| {
- trait_pred.with_self_type(self.tcx, self.tcx.mk_unit())
+ trait_pred.with_self_ty(self.tcx, self.tcx.mk_unit())
});
let unit_obligation = obligation.with(tcx, predicate);
if self.predicate_may_hold(&unit_obligation) {
fn annotate_source_of_ambiguity(
&self,
err: &mut Diagnostic,
- impls: &[DefId],
+ impls: &[ambiguity::Ambiguity],
predicate: ty::Predicate<'tcx>,
);
infer::LateBoundRegionConversionTime::HigherRankedType,
bound_predicate.rebind(data),
);
- let normalized_ty = ocx.normalize(
- &obligation.cause,
- obligation.param_env,
- self.tcx.mk_projection(data.projection_ty.def_id, data.projection_ty.substs),
- );
+ let unnormalized_term = match data.term.unpack() {
+ ty::TermKind::Ty(_) => self
+ .tcx
+ .mk_projection(data.projection_ty.def_id, data.projection_ty.substs)
+ .into(),
+ ty::TermKind::Const(ct) => self
+ .tcx
+ .mk_const(
+ ty::UnevaluatedConst {
+ def: ty::WithOptConstParam::unknown(data.projection_ty.def_id),
+ substs: data.projection_ty.substs,
+ },
+ ct.ty(),
+ )
+ .into(),
+ };
+ let normalized_term =
+ ocx.normalize(&obligation.cause, obligation.param_env, unnormalized_term);
debug!(?obligation.cause, ?obligation.param_env);
- debug!(?normalized_ty, data.ty = ?data.term);
+ debug!(?normalized_term, data.ty = ?data.term);
- let is_normalized_ty_expected = !matches!(
+ let is_normalized_term_expected = !matches!(
obligation.cause.code().peel_derives(),
ObligationCauseCode::ItemObligation(_)
| ObligationCauseCode::BindingObligation(_, _)
| ObligationCauseCode::ObjectCastObligation(..)
| ObligationCauseCode::OpaqueType
);
- let expected_ty = data.term.ty().unwrap_or_else(|| self.tcx.ty_error());
// constrain inference variables a bit more to nested obligations from normalize so
// we can have more helpful errors.
if let Err(new_err) = ocx.eq_exp(
&obligation.cause,
obligation.param_env,
- is_normalized_ty_expected,
- normalized_ty,
- expected_ty,
+ is_normalized_term_expected,
+ normalized_term,
+ data.term,
) {
- (Some((data, is_normalized_ty_expected, normalized_ty, expected_ty)), new_err)
+ (Some((data, is_normalized_term_expected, normalized_term, data.term)), new_err)
} else {
(None, error.err)
}
};
let msg = values
- .and_then(|(predicate, _, normalized_ty, expected_ty)| {
- self.maybe_detailed_projection_msg(
- predicate,
- normalized_ty.into(),
- expected_ty.into(),
- )
+ .and_then(|(predicate, _, normalized_term, expected_term)| {
+ self.maybe_detailed_projection_msg(predicate, normalized_term, expected_term)
})
.unwrap_or_else(|| format!("type mismatch resolving `{}`", predicate));
let mut diag = struct_span_err!(self.tcx.sess, obligation.cause.span, E0271, "{msg}");
let trait_def_id = pred.projection_ty.trait_def_id(self.tcx);
let self_ty = pred.projection_ty.self_ty();
- if Some(pred.projection_ty.def_id) == self.tcx.lang_items().fn_once_output() {
- Some(format!(
- "expected `{self_ty}` to be a {fn_kind} that returns `{expected_ty}`, but it returns `{normalized_ty}`",
- fn_kind = self_ty.prefix_string(self.tcx)
- ))
- } else if Some(trait_def_id) == self.tcx.lang_items().future_trait() {
- Some(format!(
- "expected `{self_ty}` to be a future that resolves to `{expected_ty}`, but it resolves to `{normalized_ty}`"
- ))
- } else if Some(trait_def_id) == self.tcx.get_diagnostic_item(sym::Iterator) {
- Some(format!(
- "expected `{self_ty}` to be an iterator that yields `{expected_ty}`, but it yields `{normalized_ty}`"
- ))
- } else {
- None
+ with_forced_trimmed_paths! {
+ if Some(pred.projection_ty.def_id) == self.tcx.lang_items().fn_once_output() {
+ Some(format!(
+ "expected `{self_ty}` to be a {fn_kind} that returns `{expected_ty}`, but it \
+ returns `{normalized_ty}`",
+ fn_kind = self_ty.prefix_string(self.tcx)
+ ))
+ } else if Some(trait_def_id) == self.tcx.lang_items().future_trait() {
+ Some(format!(
+ "expected `{self_ty}` to be a future that resolves to `{expected_ty}`, but it \
+ resolves to `{normalized_ty}`"
+ ))
+ } else if Some(trait_def_id) == self.tcx.get_diagnostic_item(sym::Iterator) {
+ Some(format!(
+ "expected `{self_ty}` to be an iterator that yields `{expected_ty}`, but it \
+ yields `{normalized_ty}`"
+ ))
+ } else {
+ None
+ }
}
}
param_env: ty::ParamEnv<'tcx>,
trait_ref_and_ty: ty::Binder<'tcx, (ty::TraitPredicate<'tcx>, Ty<'tcx>)>,
) -> PredicateObligation<'tcx> {
- let trait_pred = trait_ref_and_ty
- .map_bound(|(tr, new_self_ty)| tr.with_self_type(self.tcx, new_self_ty));
+ let trait_pred =
+ trait_ref_and_ty.map_bound(|(tr, new_self_ty)| tr.with_self_ty(self.tcx, new_self_ty));
Obligation::new(self.tcx, ObligationCause::dummy(), param_env, trait_pred)
}
let mut selcx = SelectionContext::new(&self);
match selcx.select_from_obligation(&obligation) {
Ok(None) => {
- let impls = ambiguity::recompute_applicable_impls(self.infcx, &obligation);
+ let ambiguities =
+ ambiguity::recompute_applicable_impls(self.infcx, &obligation);
let has_non_region_infer =
trait_ref.skip_binder().substs.types().any(|t| !t.is_ty_infer());
// It doesn't make sense to talk about applicable impls if there are more
// than a handful of them.
- if impls.len() > 1 && impls.len() < 10 && has_non_region_infer {
- self.annotate_source_of_ambiguity(&mut err, &impls, predicate);
+ if ambiguities.len() > 1 && ambiguities.len() < 10 && has_non_region_infer {
+ if self.tainted_by_errors().is_some() && subst.is_none() {
+ // If `subst.is_none()`, then this is probably two param-env
+ // candidates or impl candidates that are equal modulo lifetimes.
+ // Therefore, if we've already emitted an error, just skip this
+ // one, since it's not particularly actionable.
+ err.cancel();
+ return;
+ }
+ self.annotate_source_of_ambiguity(&mut err, &ambiguities, predicate);
} else {
if self.tainted_by_errors().is_some() {
err.cancel();
fn annotate_source_of_ambiguity(
&self,
err: &mut Diagnostic,
- impls: &[DefId],
+ ambiguities: &[ambiguity::Ambiguity],
predicate: ty::Predicate<'tcx>,
) {
let mut spans = vec![];
let mut crates = vec![];
let mut post = vec![];
- for def_id in impls {
- match self.tcx.span_of_impl(*def_id) {
- Ok(span) => spans.push(span),
- Err(name) => {
- crates.push(name);
- if let Some(header) = to_pretty_impl_header(self.tcx, *def_id) {
- post.push(header);
+ let mut has_param_env = false;
+ for ambiguity in ambiguities {
+ match ambiguity {
+ ambiguity::Ambiguity::DefId(impl_def_id) => {
+ match self.tcx.span_of_impl(*impl_def_id) {
+ Ok(span) => spans.push(span),
+ Err(name) => {
+ crates.push(name);
+ if let Some(header) = to_pretty_impl_header(self.tcx, *impl_def_id) {
+ post.push(header);
+ }
+ }
}
}
+ ambiguity::Ambiguity::ParamEnv(span) => {
+ has_param_env = true;
+ spans.push(*span);
+ }
}
}
let mut crate_names: Vec<_> = crates.iter().map(|n| format!("`{}`", n)).collect();
return;
}
- let msg = format!("multiple `impl`s satisfying `{}` found", predicate);
+ let msg = format!(
+ "multiple `impl`s{} satisfying `{}` found",
+ if has_param_env { " or `where` clauses" } else { "" },
+ predicate
+ );
let post = if post.len() > 1 || (post.len() == 1 && post[0].contains('\n')) {
format!(":\n{}", post.iter().map(|p| format!("- {}", p)).collect::<Vec<_>>().join("\n"),)
} else if post.len() == 1 {
projects / rust.git / blobdiff