Hint correct extern constant syntax
Error message for `extern "C" { const …}` is terse, and the right syntax is hard to guess given unfortunate difference between meaning of `static` in C and Rust.
I've added a hint for the right syntax.
Also reorder and space the list to make it clearer for futures updates
and to come closer to the original list.
Thanks @est31 for the instructions.
Fixes#43629.
r? @est31
This PR kicks off the implementation of the [default binding modes RFC][1] by
introducing the `pat_binding_modes` typeck table mentioned in the [mentoring
instructions][2].
`pat_binding_modes` is populated in `librustc_typeck/check/_match.rs` and
used wherever the HIR would be scraped prior to this PR. Unfortunately, one
blemish, namely a two callers to `contains_explicit_ref_binding`, remains.
This will likely have to be removed when the second part of [1], the
`pat_adjustments` table, is tackled. Appropriate comments have been added.
See #42640.
[1]: https://github.com/rust-lang/rfcs/pull/2005
[2]: https://github.com/rust-lang/rust/issues/42640#issuecomment-313535089
Add Span to ast::WhereClause
This PR adds `Span` field to `ast::WhereClause`. The motivation here is to make rustfmt's life easier when recovering comments before and after where clause.
r? @nrc
This is then later used by `proc_macro` to generate a new
`proc_macro::TokenTree` which preserves span information. Unfortunately this
isn't a bullet-proof approach as it doesn't handle the case when there's still
other attributes on the item, especially inner attributes.
Despite this the intention here is to solve the primary use case for procedural
attributes, attached to functions as outer attributes, likely bare. In this
situation we should be able to now yield a lossless stream of tokens to preserve
span information.
This commit adds a new field to the `Item` AST node in libsyntax to optionally
contain the original token stream that the item itself was parsed from. This is
currently `None` everywhere but is intended for use later with procedural
macros.
Point at `:` when using it instead of `;`
When triggering type ascription in such a way that we can infer a
statement end was intended, add a suggestion for the change. Always
point out the reason for the expectation of a type is due to type
ascription.
Fix#42057, #41928.
Now there's a way to add suggestions that hide the suggested code when
presented inline, to avoid weird wording when short code snippets are
added at the end.
When triggering type ascription in such a way that we can infer a
statement end was intended, add a suggestion for the change. Always
point out the reason for the expectation of a type is due to type
ascription.
