diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index d876f28040da1..6d5202bbbd3e8 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -524,6 +524,7 @@ pub enum StashKey {
MaybeFruTypo,
CallAssocMethod,
TraitMissingMethod,
+ AssociatedTypeSuggestion,
OpaqueHiddenTypeMismatch,
MaybeForgetReturn,
/// Query cycle detected, stashing in favor of a better error.
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 6bd221ff05874..3ea4df1d2a436 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -18,6 +18,7 @@ use rustc_ast::*;
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
use rustc_errors::{
codes::*, struct_span_code_err, Applicability, DiagnosticArgValue, ErrCode, IntoDiagnosticArg,
+ StashKey,
};
use rustc_hir::def::Namespace::{self, *};
use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, NonMacroAttrKind, PartialRes, PerNS};
@@ -3890,6 +3891,23 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
finalize,
) {
Ok(Some(partial_res)) if let Some(res) = partial_res.full_res() => {
+ // if we also have an associated type that matches the ident, stash a suggestion
+ if let Some(items) = self.diagnostic_metadata.current_trait_assoc_items
+ && let [Segment { ident, .. }] = path
+ && items.iter().any(|item| {
+ item.ident == *ident && matches!(item.kind, AssocItemKind::Type(_))
+ })
+ {
+ let mut diag = self.r.tcx.dcx().struct_allow("");
+ diag.span_suggestion_verbose(
+ path_span.shrink_to_lo(),
+ "there is an associated type with the same name",
+ "Self::",
+ Applicability::MaybeIncorrect,
+ );
+ diag.stash(path_span, StashKey::AssociatedTypeSuggestion);
+ }
+
if source.is_expected(res) || res == Res::Err {
partial_res
} else {
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
index 2c8d3fc9de241..e4ae244038454 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
@@ -2922,6 +2922,15 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
&mut Default::default(),
);
self.suggest_unsized_bound_if_applicable(err, obligation);
+ if let Some(span) = err.span.primary_span()
+ && let Some(mut diag) =
+ self.tcx.dcx().steal_diagnostic(span, StashKey::AssociatedTypeSuggestion)
+ && let Ok(ref mut s1) = err.suggestions
+ && let Ok(ref mut s2) = diag.suggestions
+ {
+ s1.append(s2);
+ diag.cancel()
+ }
}
}
diff --git a/tests/ui/suggestions/issue-116434-2015.rs b/tests/ui/suggestions/issue-116434-2015.rs
index 614fc27b77187..a53e2a044e93f 100644
--- a/tests/ui/suggestions/issue-116434-2015.rs
+++ b/tests/ui/suggestions/issue-116434-2015.rs
@@ -3,9 +3,12 @@ trait Foo {
fn foo() -> Clone;
//~^ WARNING trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARNING this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+ //~| HELP if this is an object-safe trait, use `dyn`
//~| WARNING trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARNING this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+ //~| HELP if this is an object-safe trait, use `dyn`
//~| ERROR the trait `Clone` cannot be made into an object [E0038]
+ //~| HELP there is an associated type with the same name
}
trait DbHandle: Sized {}
@@ -15,9 +18,12 @@ trait DbInterface {
fn handle() -> DbHandle;
//~^ WARNING trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARNING this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+ //~| HELP if this is an object-safe trait, use `dyn`
//~| WARNING trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARNING this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+ //~| HELP if this is an object-safe trait, use `dyn`
//~| ERROR the trait `DbHandle` cannot be made into an object [E0038]
+ //~| HELP there is an associated type with the same name
}
fn main() {}
diff --git a/tests/ui/suggestions/issue-116434-2015.stderr b/tests/ui/suggestions/issue-116434-2015.stderr
index 2d87029b6eb11..73a1cfa9c1d54 100644
--- a/tests/ui/suggestions/issue-116434-2015.stderr
+++ b/tests/ui/suggestions/issue-116434-2015.stderr
@@ -13,7 +13,7 @@ LL | fn foo() -> dyn Clone;
| +++
warning: trait objects without an explicit `dyn` are deprecated
- --> $DIR/issue-116434-2015.rs:15:20
+ --> $DIR/issue-116434-2015.rs:18:20
|
LL | fn handle() -> DbHandle;
| ^^^^^^^^
@@ -47,9 +47,13 @@ LL | fn foo() -> Clone;
|
= note: the trait cannot be made into an object because it requires `Self: Sized`
= note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+help: there is an associated type with the same name
+ |
+LL | fn foo() -> Self::Clone;
+ | ++++++
warning: trait objects without an explicit `dyn` are deprecated
- --> $DIR/issue-116434-2015.rs:15:20
+ --> $DIR/issue-116434-2015.rs:18:20
|
LL | fn handle() -> DbHandle;
| ^^^^^^^^
@@ -63,18 +67,22 @@ LL | fn handle() -> dyn DbHandle;
| +++
error[E0038]: the trait `DbHandle` cannot be made into an object
- --> $DIR/issue-116434-2015.rs:15:20
+ --> $DIR/issue-116434-2015.rs:18:20
|
LL | fn handle() -> DbHandle;
| ^^^^^^^^ `DbHandle` cannot be made into an object
|
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
- --> $DIR/issue-116434-2015.rs:11:17
+ --> $DIR/issue-116434-2015.rs:14:17
|
LL | trait DbHandle: Sized {}
| -------- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
+help: there is an associated type with the same name
+ |
+LL | fn handle() -> Self::DbHandle;
+ | ++++++
error: aborting due to 2 previous errors; 4 warnings emitted
diff --git a/tests/ui/suggestions/issue-116434-2021.rs b/tests/ui/suggestions/issue-116434-2021.rs
index 74c30e0cc1fbe..e7159bc2f3cd9 100644
--- a/tests/ui/suggestions/issue-116434-2021.rs
+++ b/tests/ui/suggestions/issue-116434-2021.rs
@@ -4,6 +4,7 @@ trait Foo {
type Clone;
fn foo() -> Clone;
//~^ ERROR the trait `Clone` cannot be made into an object [E0038]
+ //~| HELP there is an associated type with the same name
}
trait DbHandle: Sized {}
@@ -12,6 +13,7 @@ trait DbInterface {
type DbHandle;
fn handle() -> DbHandle;
//~^ ERROR the trait `DbHandle` cannot be made into an object [E0038]
+ //~| HELP there is an associated type with the same name
}
fn main() {}
diff --git a/tests/ui/suggestions/issue-116434-2021.stderr b/tests/ui/suggestions/issue-116434-2021.stderr
index 43ad82d484a66..a10d6ef6da4d9 100644
--- a/tests/ui/suggestions/issue-116434-2021.stderr
+++ b/tests/ui/suggestions/issue-116434-2021.stderr
@@ -6,20 +6,28 @@ LL | fn foo() -> Clone;
|
= note: the trait cannot be made into an object because it requires `Self: Sized`
= note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+help: there is an associated type with the same name
+ |
+LL | fn foo() -> Self::Clone;
+ | ++++++
error[E0038]: the trait `DbHandle` cannot be made into an object
- --> $DIR/issue-116434-2021.rs:13:20
+ --> $DIR/issue-116434-2021.rs:14:20
|
LL | fn handle() -> DbHandle;
| ^^^^^^^^ `DbHandle` cannot be made into an object
|
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
- --> $DIR/issue-116434-2021.rs:9:17
+ --> $DIR/issue-116434-2021.rs:10:17
|
LL | trait DbHandle: Sized {}
| -------- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
+help: there is an associated type with the same name
+ |
+LL | fn handle() -> Self::DbHandle;
+ | ++++++
error: aborting due to 2 previous errors