refactor match guard
This is the first step to implement RFC 2294: if-let-guard. Tracking issue: https://github.com/rust-lang/rust/issues/51114
The second step should be introducing another variant `IfLet` in the Guard enum. I separated them into 2 PRs for the convenience of reviewers.
r? @petrochenkov
Remove super old comment on function that parses items
This comment was added more than 5 years ago in ab03c1e422. As far as anyone reading this comment today needs to know, the function has never parsed items from inside an extern crate.
This comment was added more than 5 years ago in ab03c1e422. As far as
anyone reading this comment today needs to know, the function has never
parsed items from inside an extern crate.
Addressed #51602Fixed#51602
r? @estebank
here I have addressed the case where `in` was not expected right after `if` block. Speaking of `type ascription` I am not sure if this the best approach which I have implemented. Plus I think one more test case can be added to test `type-ascription` case, though I don't have any at this point of time. I will ping you again if all existing testcases pass.
The error and check for this already existed, but the parser didn't try to parse trait method arguments as patterns, so the error was never emitted. This surfaces the error, so we get better errors than simple parse errors.
Ever plagued by #43081 the compiler can return surprising spans in situations
related to procedural macros. This is exhibited by #47983 where whenever a
procedural macro is invoked in a nested item context it would fail to have
correct span information.
While #43230 provided a "hack" to cache the token stream used for each item in
the compiler it's not a full-blown solution. This commit continues to extend
this "hack" a bit more to work for nested items.
Previously in the parser the `parse_item` method would collect the tokens for an
item into a cache on the item itself. It turned out, however, that nested items
were parsed through the `parse_item_` method, so they didn't receive similar
treatment. To remedy this situation the hook for collecting tokens was moved
into `parse_item_` instead of `parse_item`.
Afterwards the token collection scheme was updated to support nested collection
of tokens. This is implemented by tracking `TokenStream` tokens instead of
`TokenTree` to allow for collecting items into streams at intermediate layers
and having them interleaved in the upper layers.
All in all, this...
Closes#47983
clarify why we're suggesting removing semicolon after braced items
Previously (issue #46186, pull-request #46258), a suggestion was added
to remove the semicolon after we fail to parse an item, but issue #51603
complains that it's still insufficiently obvious why. Let's add a note.
Resolves#51603.
Visibility spans were added to the AST in #47799 (d6bdf296) as a
`Spanned<_>`—which means that we need to choose a span even in the case
of inherited visibility (what you get when there's no `pub` &c. keyword
at all). That initial implementation's choice is pretty
counterintuitive, which could matter if we want to use it as a site to
suggest inserting a visibility modifier, &c.
(The phrase "Schelling span" in the comment is meant in analogy to the
game-theoretic concept of a "Schelling point", a value that is chosen
simply because it's what one can expect to agree upon with other agents
in the absence of explicit coördination.)
Previously (issue #46186, pull-request #46258), a suggestion was added
to remove the semicolon after we fail to parse an item, but issue #51603
complains that it's still insufficiently obvious why. Let's add a note.
Resolves#51603.
