diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index 945cdfbb0e9..75559d4f8b8 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -542,17 +542,9 @@ pub enum SelectionError<'tcx> {
ErrorReporting,
/// Multiple applicable `impl`s where found. The `DefId`s correspond to
/// all the `impl`s' Items.
- Ambiguous(Vec<AmbiguousSelection>),
+ Ambiguous(Vec<DefId>),
}
-#[derive(Copy, Clone, Debug)]
-pub enum AmbiguousSelection {
- Impl(DefId),
- ParamEnv(Span),
-}
-
-TrivialTypeTraversalAndLiftImpls! { AmbiguousSelection, }
-
/// When performing resolution, it is typically the case that there
/// can be one of three outcomes:
///
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index c1af1a05972..8a679ca005f 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -23,7 +23,7 @@ use rustc_hir::GenericParam;
use rustc_hir::Item;
use rustc_hir::Node;
use rustc_infer::infer::error_reporting::same_type_modulo_infer;
-use rustc_infer::traits::{AmbiguousSelection, TraitEngine};
+use rustc_infer::traits::TraitEngine;
use rustc_middle::traits::select::OverflowError;
use rustc_middle::ty::abstract_const::NotConstEvaluatable;
use rustc_middle::ty::error::ExpectedFound;
@@ -1403,7 +1403,7 @@ trait InferCtxtPrivExt<'hir, 'tcx> {
fn annotate_source_of_ambiguity(
&self,
err: &mut Diagnostic,
- impls: &[AmbiguousSelection],
+ impls: &[DefId],
predicate: ty::Predicate<'tcx>,
);
@@ -2036,14 +2036,6 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
);
match selcx.select_from_obligation(&obligation) {
Err(SelectionError::Ambiguous(impls)) if impls.len() > 1 => {
- if self.is_tainted_by_errors() && 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, &impls, predicate);
}
_ => {
@@ -2224,35 +2216,24 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
fn annotate_source_of_ambiguity(
&self,
err: &mut Diagnostic,
- impls: &[AmbiguousSelection],
+ impls: &[DefId],
predicate: ty::Predicate<'tcx>,
) {
let mut spans = vec![];
let mut crates = vec![];
let mut post = vec![];
- let mut or_where_clause = false;
- for ambig in impls {
- match ambig {
- AmbiguousSelection::Impl(def_id) => 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);
- }
+ 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);
}
- },
- AmbiguousSelection::ParamEnv(span) => {
- or_where_clause = true;
- spans.push(*span);
}
}
}
- let msg = format!(
- "multiple `impl`s{} satisfying `{}` found",
- if or_where_clause { " or `where` clauses" } else { "" },
- predicate
- );
+ let msg = format!("multiple `impl`s satisfying `{}` found", predicate);
let mut crate_names: Vec<_> = crates.iter().map(|n| format!("`{}`", n)).collect();
crate_names.sort();
crate_names.dedup();
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index 96d83deeeb7..6e8581128dd 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -6,11 +6,9 @@
//!
//! [rustc dev guide]:https://rustc-dev-guide.rust-lang.org/traits/resolution.html#candidate-assembly
use hir::LangItem;
-use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
-use rustc_infer::traits::util::elaborate_predicates_with_span;
-use rustc_infer::traits::{AmbiguousSelection, TraitEngine};
+use rustc_infer::traits::TraitEngine;
use rustc_infer::traits::{Obligation, SelectionError, TraitObligation};
use rustc_lint_defs::builtin::DEREF_INTO_DYN_SUPERTRAIT;
use rustc_middle::ty::print::with_no_trimmed_paths;
@@ -201,48 +199,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// and report ambiguity.
if i > 1 {
debug!("multiple matches, ambig");
-
- // Collect a list of (probable) spans that point to a param-env candidate
- let tcx = self.infcx.tcx;
- let owner = stack.obligation.cause.body_id.owner.to_def_id();
- let predicates = tcx.predicates_of(owner).instantiate_identity(tcx);
- let param_env_spans: FxHashMap<_, _> = elaborate_predicates_with_span(
- tcx,
- std::iter::zip(predicates.predicates, predicates.spans),
- )
- .filter_map(|obligation| {
- let kind = obligation.predicate.kind();
- if let ty::PredicateKind::Trait(trait_pred) = kind.skip_binder() {
- if trait_pred.trait_ref
- == ty::TraitRef::identity(tcx, trait_pred.def_id())
- .skip_binder()
- {
- // HACK: Remap the `Self: Trait` predicate that every trait has to a more useful span
- Some((
- kind.rebind(trait_pred),
- tcx.def_span(trait_pred.def_id()),
- ))
- } else {
- Some((kind.rebind(trait_pred), obligation.cause.span))
- }
- } else {
- None
- }
- })
- .collect();
-
return Err(Ambiguous(
candidates
.into_iter()
.filter_map(|c| match c.candidate {
- SelectionCandidate::ImplCandidate(def_id) => {
- Some(AmbiguousSelection::Impl(def_id))
- }
- SelectionCandidate::ParamCandidate(predicate) => {
- Some(AmbiguousSelection::ParamEnv(
- *param_env_spans.get(&predicate)?,
- ))
- }
+ SelectionCandidate::ImplCandidate(def_id) => Some(def_id),
_ => None,
})
.collect(),
diff --git a/src/test/ui/issues/issue-21974.stderr b/src/test/ui/issues/issue-21974.stderr
index 2d60b18b1f2..4e010a13653 100644
--- a/src/test/ui/issues/issue-21974.stderr
+++ b/src/test/ui/issues/issue-21974.stderr
@@ -4,13 +4,7 @@ error[E0283]: type annotations needed: cannot satisfy `&'a T: Foo`
LL | where &'a T : Foo,
| ^^^
|
-note: multiple `impl`s or `where` clauses satisfying `&'a T: Foo` found
- --> $DIR/issue-21974.rs:11:19
- |
-LL | where &'a T : Foo,
- | ^^^
-LL | &'b T : Foo
- | ^^^
+ = note: cannot satisfy `&'a T: Foo`
error: aborting due to previous error
diff --git a/src/test/ui/issues/issue-24424.stderr b/src/test/ui/issues/issue-24424.stderr
index 50d7f988e19..8f3b2ac7319 100644
--- a/src/test/ui/issues/issue-24424.stderr
+++ b/src/test/ui/issues/issue-24424.stderr
@@ -4,11 +4,7 @@ error[E0283]: type annotations needed: cannot satisfy `T0: Trait0<'l0>`
LL | impl <'l0, 'l1, T0> Trait1<'l0, T0> for bool where T0 : Trait0<'l0>, T0 : Trait0<'l1> {}
| ^^^^^^^^^^^
|
-note: multiple `impl`s or `where` clauses satisfying `T0: Trait0<'l0>` found
- --> $DIR/issue-24424.rs:4:57
- |
-LL | impl <'l0, 'l1, T0> Trait1<'l0, T0> for bool where T0 : Trait0<'l0>, T0 : Trait0<'l1> {}
- | ^^^^^^^^^^^ ^^^^^^^^^^^
+ = note: cannot satisfy `T0: Trait0<'l0>`
error: aborting due to previous error
diff --git a/src/test/ui/lifetimes/issue-34979.stderr b/src/test/ui/lifetimes/issue-34979.stderr
index a78b3eaf625..5832c4d173c 100644
--- a/src/test/ui/lifetimes/issue-34979.stderr
+++ b/src/test/ui/lifetimes/issue-34979.stderr
@@ -4,13 +4,7 @@ error[E0283]: type annotations needed: cannot satisfy `&'a (): Foo`
LL | &'a (): Foo,
| ^^^
|
-note: multiple `impl`s or `where` clauses satisfying `&'a (): Foo` found
- --> $DIR/issue-34979.rs:6:13
- |
-LL | &'a (): Foo,
- | ^^^
-LL | &'static (): Foo;
- | ^^^
+ = note: cannot satisfy `&'a (): Foo`
error: aborting due to previous error
diff --git a/src/test/ui/traits/issue-85735.stderr b/src/test/ui/traits/issue-85735.stderr
index 9e80497ca6e..fa280135beb 100644
--- a/src/test/ui/traits/issue-85735.stderr
+++ b/src/test/ui/traits/issue-85735.stderr
@@ -4,14 +4,7 @@ error[E0283]: type annotations needed: cannot satisfy `T: FnMut<(&'a (),)>`
LL | T: FnMut(&'a ()),
| ^^^^^^^^^^^^^
|
-note: multiple `impl`s or `where` clauses satisfying `T: FnMut<(&'a (),)>` found
- --> $DIR/issue-85735.rs:7:8
- |
-LL | T: FnMut(&'a ()),
- | ^^^^^^^^^^^^^
-LL |
-LL | T: FnMut(&'b ()),
- | ^^^^^^^^^^^^^
+ = note: cannot satisfy `T: FnMut<(&'a (),)>`
error: aborting due to previous error
diff --git a/src/test/ui/type/type-check/issue-40294.stderr b/src/test/ui/type/type-check/issue-40294.stderr
index d15fd23418b..75feb5698eb 100644
--- a/src/test/ui/type/type-check/issue-40294.stderr
+++ b/src/test/ui/type/type-check/issue-40294.stderr
@@ -4,13 +4,7 @@ error[E0283]: type annotations needed: cannot satisfy `&'a T: Foo`
LL | where &'a T : Foo,
| ^^^
|
-note: multiple `impl`s or `where` clauses satisfying `&'a T: Foo` found
- --> $DIR/issue-40294.rs:6:19
- |
-LL | where &'a T : Foo,
- | ^^^
-LL | &'b T : Foo
- | ^^^
+ = note: cannot satisfy `&'a T: Foo`
error: aborting due to previous error