replace `convert::Infallible` with `!` by canndrew · Pull Request #49038 · rust-lang/rust

canndrew · 2018-03-15T04:37:26Z

No description provided.

rust-highfive · 2018-03-15T04:37:37Z

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scottmcm

Horray! One step closer to stable TryFrom...

scottmcm · 2018-03-15T05:42:17Z

 }

-#[unstable(feature = "try_from", issue = "33417")]
-impl From<Infallible> for TryFromIntError {


Maybe leave this as impl From<!> For TryFromIntError? This is here so that you can use u32: TryFrom<u16> in a method returning Result<_, TryFromIntError>, which I think is still wanted. (Not for those types literally, but for when they're c_whatever aliases.)

I removed it thinking that we'd have impl<T> From<!> for T, but since we won't have that until we have specialization with intersection impls I guess I'd better add it back.

scottmcm · 2018-03-15T05:46:18Z

-/// signals to both the compiler and the user that the error case is impossible.
-#[unstable(feature = "try_from", issue = "33417")]
-#[derive(Clone,Copy,Debug,Eq,Hash,Ord,PartialEq,PartialOrd)]
-pubenumInfallible{}


Looking through that list of derives, are we missing Copy and Clone for !? They're not in the rustdoc, at least: https://doc.rust-lang.org/nightly/std/primitive.never.html#implementations
(Not a blocker for this PR, of course.)

They're implemented. No idea why they're not showing up in rustdoc.

Ah, looks like this is a nearing-three-year-old bug with primitives: #25893

canndrew · 2018-03-15T06:01:45Z

It looks like the travis failure here had nothing to do with this PR.

@alexcrichton

Replace uninhabited error enums in std with never Luckily I only found two, and one of them isn't in beta yet, so can disappear completely 😎 Are there any others I forgot? (There are lots in things like liblibc and libstd/sys, but AFAIK those don't matter, nor do things like `btree::node::LeafOrInternal` or `str::pattern::RejectAndMatch`.) The unstable `convert::Infallible` is being handled by #49038⚠️ This change may be a 1.26-or-never one. cc #48950 (comment) r? @alexcrichton

SimonSapin · 2018-03-16T14:41:25Z

tidy error: /checkout/src/libcore/num/mod.rs:3598: trailing whitespace

canndrew · 2018-03-16T15:39:02Z

Oops, thanks for pointing that out.

SimonSapin · 2018-03-17T14:37:31Z

[01:27:14] ---- [rustdoc] rustdoc/synthetic_auto/no-redundancy.rs stdout ----
[01:27:14] [01:27:14] error: htmldocck failed!
[01:27:14] status: exit code: 1
[01:27:14] command: "/usr/bin/python2.7" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/synthetic_auto/no-redundancy.stage2-x86_64-unknown-linux-gnu" "/checkout/src/test/rustdoc/synthetic_auto/no-redundancy.rs"
[01:27:14] stdout:
[01:27:14] ------------------------------------------
[01:27:14] [01:27:14] ------------------------------------------
[01:27:14] stderr:
[01:27:14] ------------------------------------------
[01:27:14] 22: @has check failed
[01:27:14] thread 'main' panicked at 'Some tests failed', tools/compiletest/src/main.rs:478:22
[01:27:14] `XPATH PATTERN` did not match
[01:27:14] // @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]/*/code' "impl<T> Send for Outer<T> where T: Copy + Send"
[01:27:14] [01:27:14] Encountered 1 errors
[01:27:14] [01:27:14] ------------------------------------------
[01:27:14] [01:27:14] thread '[rustdoc] rustdoc/synthetic_auto/no-redundancy.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:2903:9
[01:27:14] [01:27:14] [01:27:14] failures:
[01:27:14] [rustdoc] rustdoc/synthetic_auto/no-redundancy.rs

This looks like the same as #48265 (comment), you may need to swap the order of bounds in the expected rustdoc output in the comment in src/test/rustdoc/synthetic_auto/no-redundancy.rs.

Something like ./x.py test src/test/rustdoc --test-args no-redundancy should run just this test.

SimonSapin · 2018-03-17T23:04:08Z

I’ve filed #49123 for that rustdoc test failure.

SimonSapin · 2018-03-21T23:43:21Z

#49058 disabled that failing test.

@bors: r+

bors · 2018-03-21T23:43:22Z

📌 Commit 15bab45 has been approved by SimonSapin

…ver, r=SimonSapin replace `convert::Infallible` with `!`

Rollup of 23 pull requests - Successful merges: #48374, #48596, #48759, #48939, #49029, #49069, #49093, #49109, #49117, #49140, #49158, #49188, #49189, #49209, #49211, #49216, #49225, #49231, #49234, #49242, #49244, #49105, #49038 - Failed merges:

F001 · 2018-03-29T01:40:24Z

There are several empty enum types in std. For example:

implFromStrforString{typeErr = ParseError;}

My question is, are they going to be replaced by ! type ?
The type pub enum ParseError {} has been stabilized. Is it a breaking change if we replace it by ! ?

SimonSapin · 2018-03-29T05:49:58Z

This is being discussed at #49039

replace convert::Infallible with !
4647156

rust-highfive assigned sfackler Mar 15, 2018

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 15, 2018

This was referenced Mar 15, 2018
Stabilise feature(never_type). Introduce feature(exhaustive_patterns) #47630
Merged
Tracking issue for TryFrom/TryInto traits #33417
Closed

scottmcm reviewed Mar 15, 2018
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scottmcm mentioned this pull request Mar 15, 2018
Replace uninhabited error enums in std with never #49039
Closed

Add From<!> for TryFromIntError
15bab45

canndrew force-pushed the replace-infallible-with-never branch from edb2fdb to 15bab45Compare March 16, 2018 15:38

SimonSapin mentioned this pull request Mar 18, 2018
Rustdoc: where bounds order in synthetic impls is not deterministic #49123
Closed

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 21, 2018

kennytm added a commit to kennytm/rust that referenced this pull request Mar 22, 2018
Rollup merge ofrust-lang#49038- canndrew:replace-infallible-with-ne…
2c6f911
…ver, r=SimonSapin replace `convert::Infallible` with `!`

kennytm mentioned this pull request Mar 22, 2018
Rollup of 23 pull requests #49264
Merged

alexcrichton merged commit 15bab45 into rust-lang:masterMar 22, 2018

vlad20012 mentioned this pull request Mar 29, 2018
ANN: add type mismatch quick fix using TryFrom intellij-rust/intellij-rust#2403
Merged

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