syntax: add parser recovery for intersection- / and-patterns p1 @ p2
#65410
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@davidtwco Threw in two additional commits to address @varkor's review. Please take a look. :) |
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@bors r=davidtwco,varkor |
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📌 Commit 16266a5 has been approved by |
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…=davidtwco,varkor syntax: add parser recovery for intersection- / and-patterns `p1 @ p2` Fixes rust-lang#65400. The recovery comes in two flavors: 1. We know that `p2` is a binding so we can invert as `p2 @ p1`: ```rust error: pattern on wrong side of `@` --> $DIR/intersection-patterns.rs:13:9 | LL | Some(x) @ y => {} | -------^^^- | | | | | binding on the right, should be to the left | pattern on the left, should be to the right | help: switch the order: `y @ Some(x)` ``` 2. Otherwise we emit a generic diagnostic for the lack of support for intersection patterns: ```rust error: left-hand side of `@` must be a binding --> $DIR/intersection-patterns.rs:23:9 | LL | Some(x) @ Some(y) => {} | -------^^^------- | | | | | also a pattern | interpreted as a pattern, not a binding | = note: bindings are `x`, `mut x`, `ref x`, and `ref mut x` ``` For more on and-patterns, see e.g. https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/pattern-matching#and-pattern. r? @davidtwco cc @varkor @lzutao
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Rollup of 10 pull requests Successful merges: - #65170 (rustc_metadata: Privatize private code and remove dead code) - #65260 (Optimize `LexicalResolve::expansion`.) - #65261 (Remove `Option` from `TokenStream`) - #65332 (std::fmt: reorder docs) - #65340 (Several changes to the codegen backend organization) - #65365 (Include const generic arguments in metadata) - #65398 (Bring attention to suggestions when the only difference is capitalization) - #65410 (syntax: add parser recovery for intersection- / and-patterns `p1 @ p2`) - #65415 (Remove an outdated test output file) - #65416 (Minor sync changes) Failed merges: r? @ghost
Centril
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Oct 19, 2019
| // The user inverted the order, so help them fix that. | ||
| let mut applicability = Applicability::MachineApplicable; | ||
| lhs.walk(&mut |p| match p.kind { | ||
| // `check_match` is unhappy if the subpattern has a binding anywhere. |
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Fixes #65400.
The recovery comes in two flavors:
p2is a binding so we can invert asp2 @ p1:For more on and-patterns, see e.g. https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/pattern-matching#and-pattern.
r? @davidtwco
cc @varkor @lzutao