rustc_resolve: inject `uniform_paths` canaries regardless of the feature-gate, on Rust 2018. #54011

eddyb · 2018-09-06T22:04:34Z

This PR is an attempt at future-proofing "anchored paths" by emitting the same ambiguity errors that #![feature(uniform_paths)] would, with slightly changed phrasing (see added UI tests).

Also, on top of #54005, this PR allows this as well:

use crate_name;
use crate_name::foo;

In that any ambiguity between an extern crate and an import of that same crate is ignored.

r? @petrochenkov cc @aturon @Centril @joshtriplett

Centril · 2018-09-06T22:20:37Z

This looks excellent :)

petrochenkov · 2018-09-06T23:01:26Z

r=me after some decision on #53988 is made, or with #53988 removed

bors · 2018-09-07T15:19:16Z

☔ The latest upstream changes (presumably #54021) made this pull request unmergeable. Please resolve the merge conflicts.

petrochenkov · 2018-09-08T19:43:04Z

@bors r+

bors · 2018-09-08T19:43:05Z

📌 Commit 449516f has been approved by petrochenkov

@petrochenkov

…rochenkov rustc_resolve: inject `uniform_paths` canary always on Rust 2018. **NOTE**: this PR is based on rust-lang#53988, only the second commit is new. This PR is an attempt at future-proofing "anchored paths" by emitting the same ambiguity errors that `#![feature(uniform_paths)]` would, with slightly changed phrasing (see added UI tests). r? @petrochenkov cc @aturon @Centril @joshtriplett

eddyb · 2018-09-09T11:04:08Z

@bors r=petrochenkov

bors · 2018-09-09T11:04:09Z

📌 Commit 49dd5c180bdee6e6c0b2fd0ab43b20e08859a6d4 has been approved by petrochenkov

kennytm · 2018-09-09T15:34:06Z

@bors p=4

bors · 2018-09-09T20:01:36Z

⌛ Testing commit 49dd5c180bdee6e6c0b2fd0ab43b20e08859a6d4 with merge e14424d052ef6d3e4cc926c010791b240e2cfcd4...

bors · 2018-09-09T21:00:50Z

💔 Test failed - status-appveyor

bors · 2018-09-09T23:31:10Z

☔ The latest upstream changes (presumably #53778) made this pull request unmergeable. Please resolve the merge conflicts.

eddyb · 2018-09-10T05:02:46Z

That pattern doesn't work, only use crate_name; by itself does.
What I did was based on @petrochenkov's explanation that use self::x; never resolves to itself, i.e. the "cyclical" possibility is ignored.

Do we want to further expand the relaxation to ignore any ambiguity between the crate and any explicit import of the crate in question, in general?

joshtriplett · 2018-09-10T05:35:41Z

@eddyb

That pattern doesn't work, only use crate_name; by itself does.

Ah, I see; I managed to test this incorrectly. You're right, this pattern doesn't work.

Do we want to further expand the relaxation to ignore any ambiguity between the crate and any explicit import of the crate in question, in general?

If possible, yes.

eddyb · 2018-09-10T06:14:36Z

Assuming we want that relaxation,

@bors r=petrochenkov

bors · 2018-09-10T06:14:36Z

📌 Commit 962580076ae48fd528c3ce4ed2ccdfb63fe63698 has been approved by petrochenkov

bors · 2018-09-10T06:30:43Z

⌛ Testing commit 962580076ae48fd528c3ce4ed2ccdfb63fe63698 with merge 6fe2df1d16b21451b6e0e0a5c9620ee4982c5c14...

bors · 2018-09-10T07:48:41Z

💔 Test failed - status-appveyor

eddyb · 2018-09-10T08:23:05Z

RLS has a legitimate error in it:

error: `cargo` import is ambiguous
  --> tools\rls\src\build\mod.rs:15:5
   |
15 | use cargo::util::important_paths;
   |     ^^^^^ can refer to external crate `::cargo`
...
35 | mod cargo;
   | ---------- may refer to `self::cargo` in the future
   |
   = help: write `::cargo` or `self::cargo` explicitly instead
   = note: in the future, `#![feature(uniform_paths)]` may become the default
error: aborting due to previous error
[RUSTC-TIMING] rls test:false 5.373
error: Could not compile `rls`.

What should we do here?
EDIT: we're fixing it, it seems.

…ure-gate, on Rust 2018.

…t of the same crate.

eddyb · 2018-09-10T08:50:24Z

@bors r=petrochenkov

bors · 2018-09-10T08:50:25Z

📌 Commit d5da94a has been approved by petrochenkov

bors · 2018-09-10T10:28:59Z

⌛ Testing commit d5da94a with merge 5953454...

@petrochenkov

rustc_resolve: inject `uniform_paths` canaries regardless of the feature-gate, on Rust 2018. This PR is an attempt at future-proofing "anchored paths" by emitting the same ambiguity errors that `#![feature(uniform_paths)]` would, with slightly changed phrasing (see added UI tests). Also, on top of #54005, this PR allows this as well: ```rust use crate_name; use crate_name::foo; ``` In that any ambiguity between an extern crate and an import *of that same crate* is ignored. r? @petrochenkov cc @aturon @Centril @joshtriplett

bors · 2018-09-10T12:57:58Z

☀️ Test successful - status-appveyor, status-travis
Approved by: petrochenkov
Pushing 5953454 to master...

@cramertj

rustc_resolve: don't treat uniform_paths canaries as ambiguities unless they resolve to distinct Def's. In particular, this allows this pattern that @cramertj mentioned in #53130 (comment): ```rust use log::{debug, log}; fn main() { use log::{debug, log}; debug!(...); } ``` The canaries for the inner `use log::...;`, *in the macro namespace*, see the `log` macro imported at the module scope, and the (same) `log` macro, imported in the block scope inside `main`. Previously, these two possible (macro namspace) `log` resolutions would be considered ambiguous (from a forwards-compat standpoint, where we might make imports aware of block scopes). With this PR, such a case is allowed *if and only if* all the possible resolutions refer to the same definition (more specifically, because the *same* `log` macro is being imported twice). This condition subsumes previous (weaker) checks like #54005 and the second commit of #54011. Only the last commit is the main change, the other two are cleanups. r? @petrochenkov cc @Centril @joshtriplett

rust-highfive assigned petrochenkov Sep 6, 2018

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eddyb mentioned this pull request Sep 6, 2018

(Modules) Tracking issue for Picking a Module Path System variant #53130

Closed

8 tasks

petrochenkov added S-blocked Status: Blocked on something else such as an RFC or other implementation work. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 6, 2018

eddyb force-pushed the anchored-in-the-future branch from a9a6c62 to 8cd293d Compare September 7, 2018 09:15

eddyb force-pushed the anchored-in-the-future branch from 8cd293d to 449516f Compare September 7, 2018 20:25

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-blocked Status: Blocked on something else such as an RFC or other implementation work. labels Sep 8, 2018

Mark-Simulacrum mentioned this pull request Sep 8, 2018

Rollup of 11 pull requests #54068

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eddyb force-pushed the anchored-in-the-future branch from 449516f to 49dd5c1 Compare September 9, 2018 11:03

This was referenced Sep 9, 2018

resolve: Split macro prelude into built-in and user-defined parts #53936

Merged

resolve: Relax shadowing restrictions on macro-expanded macros #53778

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bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 9, 2018

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eddyb force-pushed the anchored-in-the-future branch from 49dd5c1 to 9625800 Compare September 10, 2018 06:08

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 10, 2018

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 10, 2018

eddyb mentioned this pull request Sep 10, 2018

Future-proof for #![feature(uniform_paths)]. rust-lang/rls#1052

Merged

eddyb added 2 commits September 10, 2018 11:48

rustc_resolve: inject uniform_paths canaries regardless of the feat…

0a33de0

…ure-gate, on Rust 2018.

rustc_resolve: ignore uniform_paths canaries that resolve to an impor…

d5da94a

…t of the same crate.

eddyb changed the title ~~rustc_resolve: inject uniform_paths canary always on Rust 2018.~~ rustc_resolve: inject uniform_paths canaries regardless of the feature-gate, on Rust 2018. Sep 10, 2018

eddyb force-pushed the anchored-in-the-future branch from 9625800 to d5da94a Compare September 10, 2018 08:50

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 Sep 10, 2018

bors merged commit d5da94a into rust-lang:master Sep 10, 2018

eddyb deleted the anchored-in-the-future branch September 10, 2018 13:00

bors mentioned this pull request Sep 10, 2018

Rename all mentions of nil to unit #54095

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eddyb mentioned this pull request Sep 13, 2018

rustc_resolve: don't treat uniform_paths canaries as ambiguities unless they resolve to distinct Def's. #54201

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rustc_resolve: inject `uniform_paths` canaries regardless of the feature-gate, on Rust 2018. #54011

rustc_resolve: inject `uniform_paths` canaries regardless of the feature-gate, on Rust 2018. #54011

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rustc_resolve: inject uniform_paths canaries regardless of the feature-gate, on Rust 2018. #54011

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rustc_resolve: inject `uniform_paths` canaries regardless of the feature-gate, on Rust 2018. #54011

rustc_resolve: inject `uniform_paths` canaries regardless of the feature-gate, on Rust 2018. #54011

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