Properly enforce the "patterns aren't allowed in foreign functions" rule #35015
Conversation
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Started crater run. |
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PR looks good, but I'd like to see the results of the crater run so as to decide if this should be a warning or what. |
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Hm, if we make the plain |
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Crater run failed for some reason. =( |
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Trying to restart this crater run. |
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Argh, sorry, that took a while. Here was the result: https://gist.github.com/nikomatsakis/47dea4e98ffa9d3f350838602cc2a080
Of those 6 regressions, only So, per rust-lang/rfcs#1589, So I'd be happy to land this change without a lint warning, but we are still missing a few things:
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…heck Apply the same check to function pointer types
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@nikomatsakis |
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@petrochenkov great! @bors r+ |
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📌 Commit 5c88efc has been approved by |
Properly enforce the "patterns aren't allowed in foreign functions" rule Cases like `arg @ PATTERN` or `mut arg` were missing. Apply the same rule to function pointer types. Closes #35203 [breaking-change], no breakage in sane code is expected though r? @nikomatsakis This is somewhat related to rust-lang/rfcs#1685 (cc @matklad). The goal is to eventually support full pattern syntax where it makes sense (function body may present) and to support *only* the following forms - `TYPE`, `ident: TYPE`, `_: TYPE` - where patterns don't make sense (function body doesn't present), i.e. in foreign functions and function pointer types.
Prohibit patterns in trait methods without bodies
They are not properly type checked
```rust
trait Tr {
fn f(&a: u8); // <- This compiles
}
```
, mostly rejected by the parser already and generally don't make much sense.
This PR is kind of a missing part of rust-lang#35015.
Needs crater run.
cc rust-lang#35078 (comment) rust-lang#35015 rust-lang/rfcs#1685 rust-lang#35203
r? @eddyb
Prohibit patterns in trait methods without bodies
They are not properly type checked
```rust
trait Tr {
fn f(&a: u8); // <- This compiles
}
```
, mostly rejected by the parser already and generally don't make much sense.
This PR is kind of a missing part of #35015.
Given the [statistics from crater](#37378 (comment)), the effect of this PR is mostly equivalent to improving `unused_mut` lint.
cc #35078 (comment) #35015 rust-lang/rfcs#1685 #35203
r? @eddyb
Cases like
arg @ PATTERNormut argwere missing.Apply the same rule to function pointer types.
Closes #35203
[breaking-change], no breakage in sane code is expected though
r? @nikomatsakis
This is somewhat related to rust-lang/rfcs#1685 (cc @matklad).
The goal is to eventually support full pattern syntax where it makes sense (function body may present) and to support only the following forms -
TYPE,ident: TYPE,_: TYPE- where patterns don't make sense (function body doesn't present), i.e. in foreign functions and function pointer types.