Prohibit patterns in trait methods without bodies #37378

petrochenkov · 2016-10-24T18:36:26Z

They are not properly type checked

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, the effect of this PR is mostly equivalent to improving unused_mut lint.

cc #35078 (comment) #35015 rust-lang/rfcs#1685 #35203
r? @eddyb

eddyb · 2016-10-24T19:09:46Z

Started crater run.

eddyb · 2016-10-24T21:29:06Z

Crater run looks pretty bad (177 root regressions).

petrochenkov · 2016-10-24T22:07:20Z

Something is wrong with root/non-root partitioning in crater.
Two very popular crates - rustc-serialize and num-traits have this problem, most of others seem to break because of these dependencies.
I turned the error into a deny-by-default lint, @eddyb can you run crater once more to determine the real number of root regressions? (Unless you think it's waste of resources.)

Anyway, it looks like we can't make this an error in the nearest future, but I still hope to proceed with a warn-by-default lint.

eddyb · 2016-10-24T22:09:29Z

@petrochenkov Maybe they don't show themselves? They might be broken or missing?

EDIT: started a second run, only on the "after" half.

traits: Remove pattern in trait's method signature This use of `mut` was nonsensical for now, but is proposed to be disallowed by rustc in the future (as a bugfix). See rust-lang/rust/pull/37378 for context.

eddyb · 2016-10-25T01:21:27Z

Second crater report shows only 22 root regressions.

petrochenkov · 2016-10-25T19:46:18Z

mut arg - 19 crates (if only unused_mut worked in this context...).
&arg - 3 crates.

I've updated the PR with warning-by-default and tracking issue number.
Also #35203 needs to be reopened (I have no rights to do it).

eddyb · 2016-10-25T22:01:12Z

@bors r+

bors · 2016-10-25T22:01:14Z

📌 Commit 82d4200 has been approved by eddyb

@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 rust-lang#35015. Needs crater run. cc rust-lang#35078 (comment) rust-lang#35015 rust-lang/rfcs#1685 rust-lang#35203 r? @eddyb

Manishearth · 2016-10-26T11:20:32Z

Fails tidy, d230a7e

TimNN · 2016-10-26T11:20:39Z

The used error code (E0570) has been merged by a different PR (#36421) since this PR was opened (thus this PR currently fails travis when merged).

Manishearth · 2016-10-26T11:24:28Z

src/librustc_passes/diagnostics.rs

@@ -228,4 +228,5 @@ pub impl Foo for Bar {
 register_diagnostics! {
    E0472, // asm! is unsupported on this target
    E0561, // patterns aren't allowed in function pointer types
+    E0570, // patterns aren't allowed in methods without bodies


This seems to be unused?

retep998 · 2016-10-26T15:21:43Z

I believe this caused #37416 to fail

https://buildbot.rust-lang.org/builders/auto-win-msvc-64-cargotest/builds/2155

error: patterns aren't allowed in methods without bodies
   --> tests\cargotest\support/mod.rs:604:34
    |
604 |     fn tap<F: FnOnce(&mut Self)>(mut self, callback: F) -> Self;
    |                                  ^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #35203 <https://github.com/rust-lang/rust/issues/35203>
note: lint level defined here
   --> tests\cargotest\lib.rs:1:9
    |
1   | #![deny(warnings)]
    |         ^^^^^^^^

error: aborting due to previous error

Fix rust-lang/rust#35203 warning/error rust-lang/rust#35203 made patterns in functions without body into a warn by default lint (which is being `deny`ed here). cc rust-lang/rust#37378, rust-lang/rust#37416

petrochenkov · 2016-10-26T18:37:27Z

@bors r=eddyb

bors · 2016-10-26T18:37:39Z

📌 Commit 811a2b9 has been approved by eddyb

bors · 2016-10-29T03:21:19Z

⌛ Testing commit 811a2b9 with merge e61c918...

bors · 2016-10-29T04:31:25Z

💔 Test failed - auto-win-msvc-64-cargotest

TimNN · 2016-10-29T05:30:03Z

This probably needs to update the sha at https://github.com/rust-lang/rust/blob/master/src/tools/cargotest/main.rs#L27 to at least rust-lang/cargo@806e3c3

petrochenkov · 2016-10-29T10:20:19Z

@bors r=eddyb

bors · 2016-10-29T10:20:20Z

📌 Commit 4ca11ce has been approved by eddyb

bors · 2016-10-29T12:41:06Z

⌛ Testing commit 4ca11ce with merge 75a87c5...

@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

bors · 2016-10-29T15:54:28Z

WaDelma · 2016-11-14T06:08:14Z

@petrochenkov
Hey that crater run that said 22 root regressions didn't fail to build my crate even though it quite few anonymous parameters in traits (poisson::algorithm::Creator and poisson::algorithm::Algorithm). Was the lint broken or is there something I am missing?

Edit. Ah the first one was broken already from rustc-serialize and num-traits and didn't reveal that the crate would fail to build even without them...

(And this is why I would really like central place to check crater runs...)

petrochenkov · 2016-11-14T09:28:34Z

@WaDelma
This lint reports patterns in parameters of trait methods without body

fn f(&arg: Type);
fn g(mut arg: Type);

, anonymous parameters

fn h(Type);

are not reported (yet, waiting for rust-lang/rfcs#1685).

WaDelma · 2016-11-14T10:06:34Z

Ah okay. That was the part I was missing. :D

rust-highfive assigned eddyb Oct 24, 2016

petrochenkov force-pushed the nopat branch from f4cc508 to e41f9c9 Compare October 24, 2016 22:03

bluss mentioned this pull request Oct 24, 2016

traits: Remove pattern in trait's method signature rust-num/num#238

Merged

petrochenkov mentioned this pull request Oct 25, 2016

Tracking issue for future-incompatibility lint patterns_in_fns_without_body #35203

Open

6 tasks

petrochenkov force-pushed the nopat branch from e41f9c9 to 82d4200 Compare October 25, 2016 19:44

Manishearth mentioned this pull request Oct 26, 2016

Rollup of 11 pull requests #37416

Closed

Manishearth added a commit to Manishearth/rust that referenced this pull request Oct 26, 2016

Remove duplicate error code (fixup rust-lang#37378)

d230a7e

Manishearth reviewed Oct 26, 2016

View reviewed changes

TimNN mentioned this pull request Oct 26, 2016

Fix rust-lang/rust#35203 warning/error rust-lang/cargo#3231

Merged

Prohibit patterns in trait methods without bodies

811a2b9

petrochenkov force-pushed the nopat branch from 82d4200 to 811a2b9 Compare October 26, 2016 18:36

Update cargo sha for cargotest

4ca11ce

bors merged commit 4ca11ce into rust-lang:master Oct 29, 2016

bors mentioned this pull request Oct 29, 2016

detect extra region requirements in impls #37167

Merged

bluss mentioned this pull request Nov 1, 2016

Bounds parsing refactoring #37511

Closed

petrochenkov deleted the nopat branch March 16, 2017 19:40

varkor mentioned this pull request Aug 4, 2018

Allow destructuring parameters in trait function declarations #53046

Open

saleemrashid mentioned this pull request Nov 19, 2018

Error on compilation for verifying MPC on macOS zcash/mpc#11

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Prohibit patterns in trait methods without bodies #37378

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Prohibit patterns in trait methods without bodies #37378

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