resolve: clean up the semantics of `self` in an import list #38313

jseyfried · 2016-12-12T03:59:04Z

Change self in an import list use foo::bar::{self, ...}; to import bar only in the type namespace. Today, bar is imported in every namespace in which foo::bar is defined.

This is a [breaking-change], see #38293 (comment) for examples of code that would break.

Fixes #38293.
r? @nrc

jseyfried · 2016-12-12T04:41:45Z

Like this case, a partial warning cycle is doable but a full warning cycle would be fairly invasive.

petrochenkov · 2016-12-12T09:50:30Z

I think import prefixes need to be consistently restricted to modules and enums, rather than to all things in type namespace

type T = u8;
use T::*; // Not OK
use T::{}; // Not OK (#38012)
use T::{self}; // Not OK

AFAIU, use T::{self}; still compiles after this patch

jseyfried · 2016-12-12T10:21:34Z

@petrochenkov
I agree that import prefixes should be restricted to modules and enums, but I'd like to do that in a separate PR that also fixes #38012, unifies error messages with use path::to::Trait::*; (already disallowed in a special case), and forbids traits and enums in pub(path). These extra restrictions on the type namespace are easy to phase in with a warning cycle.

petrochenkov · 2016-12-12T11:04:25Z

@jseyfried

fixes #38012 ... and forbids traits and enums in pub(path)

This is already done in #38154, btw.

EDIT: And I'd like to somehow extend the error infrastructure from #38154 on import paths as well, but didn't started yet.

jseyfried · 2016-12-12T11:18:43Z

Oh nice, forgot about that.

In that case, I'll restrict to modules/enums and unify with use path::to::Trait::*;-checking when I refactor ImportDirective to improve diagnostics for import lists.

nrc

r=me with the comment in the test

nrc · 2016-12-19T00:08:41Z

src/test/compile-fail/issue-38293.rs

+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+


Could you add a comment saying what is being tested please?

ping @jseyfried I think a comment here is the only thing holding up this PR?

@pnkfelix
@nrc and I decided (on irc) to land this with a partial warning cycle, which I still need to implement. I expect to get to it this week.

bors · 2016-12-21T02:54:47Z

☔ The latest upstream changes (presumably #38499) made this pull request unmergeable. Please resolve the merge conflicts.

brson · 2016-12-22T00:43:49Z

I have made some fixes to crater and am attempting to run it on this pr.

brson · 2016-12-22T18:29:01Z

Still working through crater fixes, but I think I'll have a result soon.

brson · 2016-12-22T22:41:01Z

Crater says https://gist.github.com/anonymous/05481ded38d24acb0c322ba735c78054

jseyfried · 2016-12-22T22:49:58Z

@brson Thanks! Looks like all of those regressions are spurious (curl: (18) transfer closed with _ bytes remaining to read).

… a module or enum `foo`.

jseyfried · 2017-01-10T06:16:26Z

@nrc I added a best-effort warning.

Right now, the warning uses the legacy_import lint from #38271 (we can still deny legacy_imports without causing breakage on Crater). Is it worth adding a new lint?

nrc · 2017-01-11T18:42:19Z

re-using legacy_imports seems fine to me

@bors: r+

bors · 2017-01-11T18:42:20Z

📌 Commit d86e487 has been approved by nrc

bors · 2017-01-11T20:12:01Z

⌛ Testing commit d86e487 with merge b27c709...

@nrc

resolve: clean up the semantics of `self` in an import list Change `self` in an import list `use foo::bar::{self, ...};` to import `bar` only in the type namespace. Today, `bar` is imported in every namespace in which `foo::bar` is defined. This is a [breaking-change], see #38293 (comment) for examples of code that would break. Fixes #38293. r? @nrc

bors · 2017-01-11T22:33:38Z

☀️ Test successful - status-appveyor, status-travis
Approved by: nrc
Pushing b27c709 to master...

Version 1.16.0 (2017-03-16) =========================== Language -------- * Lifetimes in statics and consts default to `'static`. [RFC 1623] * [The compiler's `dead_code` lint now accounts for type aliases][38051]. * [Uninhabitable enums (those without any variants) no longer permit wildcard match patterns][38069] * [Clean up semantics of `self` in an import list][38313] * [`Self` may appear in `impl` headers][38920] * [`Self` may appear in struct expressions][39282] Compiler -------- * [`rustc` now supports `--emit=metadata`, which causes rustc to emit a `.rmeta` file containing only crate metadata][38571]. This can be used by tools like the Rust Language Service to perform metadata-only builds. * [Levenshtein based typo suggestions now work in most places, while previously they worked only for fields and sometimes for local variables][38927]. Together with the overhaul of "no resolution"/"unexpected resolution" errors (#[38154]) they result in large and systematic improvement in resolution diagnostics. * [Fix `transmute::<T, U>` where `T` requires a bigger alignment than `U`][38670] * [rustc: use -Xlinker when specifying an rpath with ',' in it][38798] * [`rustc` no longer attempts to provide "consider using an explicit lifetime" suggestions][37057]. They were inaccurate. Stabilized APIs --------------- * [`VecDeque::truncate`] * [`VecDeque::resize`] * [`String::insert_str`] * [`Duration::checked_add`] * [`Duration::checked_sub`] * [`Duration::checked_div`] * [`Duration::checked_mul`] * [`str::replacen`] * [`str::repeat`] * [`SocketAddr::is_ipv4`] * [`SocketAddr::is_ipv6`] * [`IpAddr::is_ipv4`] * [`IpAddr::is_ipv6`] * [`Vec::dedup_by`] * [`Vec::dedup_by_key`] * [`Result::unwrap_or_default`] * [`<*const T>::wrapping_offset`] * [`<*mut T>::wrapping_offset`] * `CommandExt::creation_flags` * [`File::set_permissions`] * [`String::split_off`] Libraries --------- * [`[T]::binary_search` and `[T]::binary_search_by_key` now take their argument by `Borrow` parameter][37761] * [All public types in std implement `Debug`][38006] * [`IpAddr` implements `From<Ipv4Addr>` and `From<Ipv6Addr>`][38327] * [`Ipv6Addr` implements `From<[u16; 8]>`][38131] * [Ctrl-Z returns from `Stdin.read()` when reading from the console on Windows][38274] * [std: Fix partial writes in `LineWriter`][38062] * [std: Clamp max read/write sizes on Unix][38062] * [Use more specific panic message for `&str` slicing errors][38066] * [`TcpListener::set_only_v6` is deprecated][38304]. This functionality cannot be achieved in std currently. * [`writeln!`, like `println!`, now accepts a form with no string or formatting arguments, to just print a newline][38469] * [Implement `iter::Sum` and `iter::Product` for `Result`][38580] * [Reduce the size of static data in `std_unicode::tables`][38781] * [`char::EscapeDebug`, `EscapeDefault`, `EscapeUnicode`, `CaseMappingIter`, `ToLowercase`, `ToUppercase`, implement `Display`][38909] * [`Duration` implements `Sum`][38712] * [`String` implements `ToSocketAddrs`][39048] Cargo ----- * [The `cargo check` command does a type check of a project without building it][cargo/3296] * [crates.io will display CI badges from Travis and AppVeyor, if specified in Cargo.toml][cargo/3546] * [crates.io will display categories listed in Cargo.toml][cargo/3301] * [Compilation profiles accept integer values for `debug`, in addition to `true` and `false`. These are passed to `rustc` as the value to `-C debuginfo`][cargo/3534] * [Implement `cargo --version --verbose`][cargo/3604] * [All builds now output 'dep-info' build dependencies compatible with make and ninja][cargo/3557] * [Build all workspace members with `build --all`][cargo/3511] * [Document all workspace members with `doc --all`][cargo/3515] * [Path deps outside workspace are not members][cargo/3443] Misc ---- * [`rustdoc` has a `--sysroot` argument that, like `rustc`, specifies the path to the Rust implementation][38589] * [The `armv7-linux-androideabi` target no longer enables NEON extensions, per Google's ABI guide][38413] * [The stock standard library can be compiled for Redox OS][38401] * [Rust has initial SPARC support][38726]. Tier 3. No builds available. * [Rust has experimental support for Nvidia PTX][38559]. Tier 3. No builds available. * [Fix backtraces on i686-pc-windows-gnu by disabling FPO][39379] Compatibility Notes ------------------- * [Uninhabitable enums (those without any variants) no longer permit wildcard match patterns][38069] * In this release, references to uninhabited types can not be pattern-matched. This was accidentally allowed in 1.15. * [The compiler's `dead_code` lint now accounts for type aliases][38051]. * [Ctrl-Z returns from `Stdin.read()` when reading from the console on Windows][38274] * [Clean up semantics of `self` in an import list][38313] [37057]: rust-lang/rust#37057 [37761]: rust-lang/rust#37761 [38006]: rust-lang/rust#38006 [38051]: rust-lang/rust#38051 [38062]: rust-lang/rust#38062 [38062]: rust-lang/rust#38622 [38066]: rust-lang/rust#38066 [38069]: rust-lang/rust#38069 [38131]: rust-lang/rust#38131 [38154]: rust-lang/rust#38154 [38274]: rust-lang/rust#38274 [38304]: rust-lang/rust#38304 [38313]: rust-lang/rust#38313 [38314]: rust-lang/rust#38314 [38327]: rust-lang/rust#38327 [38401]: rust-lang/rust#38401 [38413]: rust-lang/rust#38413 [38469]: rust-lang/rust#38469 [38559]: rust-lang/rust#38559 [38571]: rust-lang/rust#38571 [38580]: rust-lang/rust#38580 [38589]: rust-lang/rust#38589 [38670]: rust-lang/rust#38670 [38712]: rust-lang/rust#38712 [38726]: rust-lang/rust#38726 [38781]: rust-lang/rust#38781 [38798]: rust-lang/rust#38798 [38909]: rust-lang/rust#38909 [38920]: rust-lang/rust#38920 [38927]: rust-lang/rust#38927 [39048]: rust-lang/rust#39048 [39282]: rust-lang/rust#39282 [39379]: rust-lang/rust#39379 [`<*const T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset [`<*mut T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset [`Duration::checked_add`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_add [`Duration::checked_div`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_div [`Duration::checked_mul`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_mul [`Duration::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_sub [`File::set_permissions`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.set_permissions [`IpAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv4 [`IpAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv6 [`Result::unwrap_or_default`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_or_default [`SocketAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv4 [`SocketAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv6 [`String::insert_str`]: https://doc.rust-lang.org/std/string/struct.String.html#method.insert_str [`String::split_off`]: https://doc.rust-lang.org/std/string/struct.String.html#method.split_off [`Vec::dedup_by_key`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by_key [`Vec::dedup_by`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by [`VecDeque::resize`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.resize [`VecDeque::truncate`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.truncate [`str::repeat`]: https://doc.rust-lang.org/std/primitive.str.html#method.repeat [`str::replacen`]: https://doc.rust-lang.org/std/primitive.str.html#method.replacen [cargo/3296]: rust-lang/cargo#3296 [cargo/3301]: rust-lang/cargo#3301 [cargo/3443]: rust-lang/cargo#3443 [cargo/3511]: rust-lang/cargo#3511 [cargo/3515]: rust-lang/cargo#3515 [cargo/3534]: rust-lang/cargo#3534 [cargo/3546]: rust-lang/cargo#3546 [cargo/3557]: rust-lang/cargo#3557 [cargo/3604]: rust-lang/cargo#3604 [RFC 1623]: https://github.com/rust-lang/rfcs/blob/master/text/1623-static.md

rust-highfive assigned nrc Dec 12, 2016

jseyfried force-pushed the self_imports branch from 491a99e to ed5d0f5 Compare December 12, 2016 04:45

jseyfried mentioned this pull request Dec 12, 2016

Non-modules allowed in module positions in use. #38293

Closed

jseyfried mentioned this pull request Dec 12, 2016

Empty import lists are too permissive #38012

Closed

jseyfried force-pushed the self_imports branch from ed5d0f5 to 24b9ca5 Compare December 15, 2016 06:03

nrc approved these changes Dec 19, 2016

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jseyfried added the S-waiting-on-crater Status: Waiting on a crater run to be completed. label Dec 20, 2016

jseyfried removed the S-waiting-on-crater Status: Waiting on a crater run to be completed. label Dec 23, 2016

pnkfelix added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jan 3, 2017

jseyfried force-pushed the self_imports branch from 24b9ca5 to 1c449b4 Compare January 10, 2017 05:51

jseyfried added 2 commits January 10, 2017 05:54

Change self in an import list use foo::{self, ...} to only import…

235a7a7

… a module or enum `foo`.

Start warning cycle.

d86e487

jseyfried force-pushed the self_imports branch from 1c449b4 to d86e487 Compare January 10, 2017 05:54

nrc closed this Jan 11, 2017

nrc reopened this Jan 11, 2017

bors merged commit d86e487 into rust-lang:master Jan 11, 2017

jseyfried deleted the self_imports branch January 17, 2017 22:59

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resolve: clean up the semantics of `self` in an import list #38313

resolve: clean up the semantics of `self` in an import list #38313

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resolve: clean up the semantics of self in an import list #38313

resolve: clean up the semantics of self in an import list #38313

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resolve: clean up the semantics of `self` in an import list #38313

resolve: clean up the semantics of `self` in an import list #38313

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