Extend `unnecessary_to_owned` to handle `Borrow` trait in map types
Fixes https://github.com/rust-lang/rust-clippy/issues/8088.
Alternative to #12315.
r? `@y21`
changelog: Extend `unnecessary_to_owned` to handle `Borrow` trait in map types
----
UPDATE: add async block into test.
FIX: no_effect
Fixed asynchronous function parameter names with underscores so that warnings are not displayed when underscores are added to parameter names
ADD: test case
There are lots of functions that modify a diagnostic. This can be via a
`&mut Diagnostic` or a `&mut DiagnosticBuilder`, because the latter type
wraps the former and impls `DerefMut`.
This commit converts all the `&mut Diagnostic` occurrences to `&mut
DiagnosticBuilder`. This is a step towards greatly simplifying
`Diagnostic`. Some of the relevant function are made generic, because
they deal with both errors and warnings. No function bodies are changed,
because all the modifier methods are available on both `Diagnostic` and
`DiagnosticBuilder`.
This mostly works well, and eliminates a couple of delayed bugs.
One annoying thing is that we should really also add an
`ErrorGuaranteed` to `proc_macro::bridge::LitKind::Err`. But that's
difficult because `proc_macro` doesn't have access to `ErrorGuaranteed`,
so we have to fake it.
Ignore imported items in `min_ident_chars`
Suppress the `min_ident_chars` warning for items whose name we cannot control. Do not warn for `use a::b`, but warn for `use a::b as c`, since `c` is a local identifier.
Fixes#12232
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`min_ident_chars`]: Do not warn on non-local identifiers
[`incompatible_msrv`]: allow expressions that come from desugaring
Fixes#12273
changelog: [`incompatible_msrv`]: don't lint on the `IntoFuture::into_future` call desugared by `.await`
Suppress the `min_ident_chars` warning for items whose name we cannot
control. Do not warn for `use a::b`, but warn for `use a::b as c`, since
`c` is a local identifier.
Fixes#12232
