mirror of https://github.com/rust-lang/rust.git
f41ad1bc9c
Tweak suggestions for bare trait used as a type
```
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/not-on-bare-trait-2021.rs:11:11
|
LL | fn bar(x: Foo) -> Foo {
| ^^^
|
help: use a generic type parameter, constrained by the trait `Foo`
|
LL | fn bar<T: Foo>(x: T) -> Foo {
| ++++++++ ~
help: you can also use `impl Foo`, but users won't be able to specify the type paramer when calling the `fn`, having to rely exclusively on type inference
|
LL | fn bar(x: impl Foo) -> Foo {
| ++++
help: alternatively, use a trait object to accept any type that implements `Foo`, accessing its methods at runtime using dynamic dispatch
|
LL | fn bar(x: &dyn Foo) -> Foo {
| ++++
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/not-on-bare-trait-2021.rs:11:19
|
LL | fn bar(x: Foo) -> Foo {
| ^^^
|
help: use `impl Foo` to return an opaque type, as long as you return a single underlying type
|
LL | fn bar(x: Foo) -> impl Foo {
| ++++
help: alternatively, you can return an owned trait object
|
LL | fn bar(x: Foo) -> Box<dyn Foo> {
| +++++++ +
```
Fix #119525:
```
error[E0038]: the trait `Ord` cannot be made into an object
--> $DIR/bare-trait-dont-suggest-dyn.rs:3:33
|
LL | fn ord_prefer_dot(s: String) -> Ord {
| ^^^ `Ord` 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>
--> $SRC_DIR/core/src/cmp.rs:LL:COL
|
= note: the trait cannot be made into an object because it uses `Self` as a type parameter
::: $SRC_DIR/core/src/cmp.rs:LL:COL
|
= note: the trait cannot be made into an object because it uses `Self` as a type parameter
help: consider using an opaque type instead
|
LL | fn ord_prefer_dot(s: String) -> impl Ord {
| ++++
```
|
||
|---|---|---|
| .. | ||
| auxiliary | ||
| check-cfg | ||
| coverage | ||
| doctest | ||
| error-in-impl-trait | ||
| generate-link-to-definition | ||
| intra-doc | ||
| issues | ||
| lints | ||
| scrape-examples | ||
| suggestions | ||
| ambiguous-inherent-assoc-ty.rs | ||
| apit-46976.rs | ||
| bounded-hr-lifetime.rs | ||
| bounded-hr-lifetime.stderr | ||
| check-doc-alias-attr-location.rs | ||
| check-doc-alias-attr-location.stderr | ||
| check-doc-alias-attr.rs | ||
| check-doc-alias-attr.stderr | ||
| circular-intra-doc-link-48414.rs | ||
| commandline-argfile-badutf8.args | ||
| commandline-argfile-badutf8.rs | ||
| commandline-argfile-badutf8.stderr | ||
| commandline-argfile-missing.rs | ||
| commandline-argfile-missing.stderr | ||
| commandline-argfile.args | ||
| commandline-argfile.rs | ||
| const-evalutation-ice.rs | ||
| const-evalutation-ice.stderr | ||
| const_arg_in_type_position.rs | ||
| const_arg_in_type_position.stderr | ||
| crate-reference-in-block-module.rs | ||
| crate-reference-in-block-module.stderr | ||
| custom_code_classes_in_docs-warning.rs | ||
| custom_code_classes_in_docs-warning.stderr | ||
| custom_code_classes_in_docs-warning3.rs | ||
| custom_code_classes_in_docs-warning3.stderr | ||
| deprecated-attrs.rs | ||
| deprecated-attrs.stderr | ||
| deref-generic.rs | ||
| diagnostic-width.rs | ||
| diagnostic-width.stderr | ||
| doc-alias-assoc-const.rs | ||
| doc-alias-assoc-const.stderr | ||
| doc-alias-crate-level.rs | ||
| doc-alias-crate-level.stderr | ||
| doc-alias-same-name.rs | ||
| doc-alias-same-name.stderr | ||
| doc-cfg.rs | ||
| doc-cfg.stderr | ||
| doc-include-suggestion.rs | ||
| doc-include-suggestion.stderr | ||
| feature-gate-custom_code_classes_in_docs.rs | ||
| feature-gate-custom_code_classes_in_docs.stderr | ||
| feature-gate-doc_cfg_hide.rs | ||
| feature-gate-doc_cfg_hide.stderr | ||
| hidden-trait-method-34423.rs | ||
| ice-assoc-const-for-primitive-31808.rs | ||
| ice-bug-report-url.rs | ||
| ice-bug-report-url.stderr | ||
| ignore-block-help.rs | ||
| ignore-block-help.stderr | ||
| impl-fn-nesting.rs | ||
| impl-fn-nesting.stderr | ||
| infinite-recursive-type.rs | ||
| infinite-recursive-type.stderr | ||
| inherent-assoc-consts-36031.rs | ||
| invalid-cfg.rs | ||
| invalid-cfg.stderr | ||
| invalid-keyword.rs | ||
| invalid-keyword.stderr | ||
| invalid-syntax.rs | ||
| invalid-syntax.stderr | ||
| invalid-theme-name.rs | ||
| invalid-theme-name.stderr | ||
| invalid_associated_const.rs | ||
| invalid_associated_const.stderr | ||
| invalid_const_in_lifetime_position.rs | ||
| invalid_const_in_lifetime_position.stderr | ||
| invalid_infered_static_and_const.rs | ||
| invalid_infered_static_and_const.stderr | ||
| issue-102467.rs | ||
| issue-102467.stderr | ||
| issue-110629-private-type-cycle-dyn.rs | ||
| issue-110629-private-type-cycle-dyn.stderr | ||
| issue-110629-private-type-cycle.rs | ||
| macro-docs.rs | ||
| macro-docs.stderr | ||
| macro-docs.stdout | ||
| mismatched_arg_count.rs | ||
| mismatched_arg_count.stderr | ||
| nested-extern-crate-46271.rs | ||
| nested-macro-rules-47639.rs | ||
| normalize-cycle.rs | ||
| normalize-overflow.rs | ||
| not-wf-ambiguous-normalization.rs | ||
| not-wf-ambiguous-normalization.stderr | ||
| output-format-html-stable.rs | ||
| proc_macro_bug.rs | ||
| proc_macro_bug.stderr | ||
| range-pattern.rs | ||
| recursive-deref-ice.rs | ||
| rustc-check-passes.rs | ||
| rustc-check-passes.stderr | ||
| search-index-generics-recursion-bug-issue-59502.rs | ||
| super-glob-40936.rs | ||
| track-diagnostics.rs | ||
| track-diagnostics.stderr | ||
| tuple-variadic-check.rs | ||
| tuple-variadic-check.stderr | ||
| unable-fulfill-trait.rs | ||
| unable-fulfill-trait.stderr | ||
| unescaped_backticks.rs | ||
| unescaped_backticks.stderr | ||
| unused-extern-crate.rs | ||
| use_both_out_dir_and_output_options.rs | ||
| use_both_out_dir_and_output_options.stderr | ||
| wasm-safe.rs | ||