NLL: User type annotations refactor, associated constant patterns and ref bindings. #55937

davidtwco · 2018-11-13T21:59:27Z

Fixes #55511 and Fixes #55401. Contributes to #54943.

This PR performs a large refactoring on user type annotations, checks user type annotations for associated constants in patterns and that user type annotations for ref bindings are respected.

r? @nikomatsakis

src/librustc/mir/mod.rs

src/librustc/mir/visit.rs

src/librustc_mir/borrow_check/nll/type_check/mod.rs

nikomatsakis

Looks great! Left one nit.

r=me once tests passed and comment is added

src/librustc_mir/borrow_check/nll/type_check/mod.rs

davidtwco · 2018-11-22T23:12:25Z

Pushed the first version of this that does what it says on the tin. Will need a fresh review as a lot has changed.

davidtwco · 2018-11-24T12:01:42Z

Added a fix for #55511 to this PR. Still seeing an ICE on three tests for the original fix, worked out that is due to this addition:

https://github.com/rust-lang/rust/blob/bde1f0d98bd1927baf5f53bd5c0d54d1382f1c45/src/librustc_traits/type_op.rs#L151-L154

But without that addition, the test change in src/test/ui/regions/regions-free-region-ordering-caller1.rs doesn't happen. Still working on it.

davidtwco · 2018-11-25T14:27:02Z

Added a fix for #55401 too. Yet to look into the failures for the original PR issue.

Xanewok · 2019-01-02T15:50:24Z

I'm not sure I understand the fallout here.

   Compiling rls v1.31.6 (/home/xanewok/repos/rust/src/tools/rls)
error[E0621]: explicit lifetime required in the type of `msg`======> ] 245/246: rls(bin)
   --> src/tools/rls/src/server/mod.rs:185:21
    |
173 |       fn dispatch_message(&mut self, msg: &RawMessage) -> Result<(), jsonrpc::Error> {
    |                                           ----------- help: add explicit lifetime `'static` to the type of `msg`: `&'static server::message::RawMessage`
...
185 |                       <$n_action as LSPNotification>::METHOD => {
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetime `'static` required
...
259 | /         match_action!(
260 | |             msg.method;
261 | |             notifications:
262 | |                 notifications::Initialized,
...   |
287 | |                 requests::CodeLensRequest;
288 | |         );
    | |__________- in this macro invocation
error: aborting due to previous error

With $method being expanded to msg.method (which itself is of type String), we match on $method.as_str() and handle associated constants of type &'static str.

Indeed, matched value msg.method.as_str() will be of shorter lifetime (let's say &'a str) than the arms (associated constants of &'static str type) but I don't understand why that's an error. Shouldn't it be the other way around, that the match arms should live at least as long as the matched value? Am I missing something?

This exchanges a compilation error for a warning-but-future-error but at least it compiles now and I'm not exactly sure how to fix it without cloning those `METHOD` constants on every match (which is less than ideal, to say the least).

nikomatsakis · 2019-01-02T19:48:44Z

I filed #57280, as this seems like a bug (and a regression).

Work around rust-lang/rust#55937

Breakage was due to rust-lang#55937, which seemed to introduce a regression (tracked over at rust-lang#57280).

Changes: ```` Update Clippy Move TestFailures when collecting failures Update languageserver-types to 0.51.1 update clippy hash and rustc_tools_util and use rustc_tools_util from crates.io Work around rust-lang#55937 Update Clippy... again Update Clippy Update clippy ````

@oli-obk

submodules: update clippy and rls Fixes clippy toolstate Changes: ```` Update to latest compiletest-rs release add testcase for #3462 deps: bump rustc_tools_util version from 0.1.0 to 0.1.1 just in case... rustc_tool_utils: fix failure to create proper non-repo version string when used in crates on crates.io, bump version UI test cleanup: Extract ifs_same_cond tests UI test cleanup: Extract for_kv_map lint tests Fix test for #57250 Limit infinite_iter collect() check to known types Some improvements to util documentation Use hashset for name blacklist Reformat random_state tests Use node_id_to_type_opt instead of node_it_to_type in random_state Check pattern equality while checking declaration equality random_state lint Use an FxHashSet for valid idents in documentation lint Fix suggestion for unnecessary_ref lint Update CONTRIBUTING.md for rustfix tests Update .fixed files via update-references.sh Run rustfix on first UI test Use WIP branch for compiletest_rs ```` Also updates RLS and removes the patching of rustc_tool_utils from cargo.toml RLS changes: ```` update clippy hash and rustc_tools_util and use rustc_tools_util from crates.io Work around #55937 Update Clippy... again Update Clippy Update clippy ```` r? @oli-obk

Changes: ```` Update Clippy Move TestFailures when collecting failures Update languageserver-types to 0.51.1 update clippy hash and rustc_tools_util and use rustc_tools_util from crates.io Work around rust-lang#55937 Update Clippy... again Update Clippy Update clippy ````

@oli-obk

submodules: update clippy and rls Fixes clippy toolstate Changes: ```` Update to latest compiletest-rs release add testcase for #3462 deps: bump rustc_tools_util version from 0.1.0 to 0.1.1 just in case... rustc_tool_utils: fix failure to create proper non-repo version string when used in crates on crates.io, bump version UI test cleanup: Extract ifs_same_cond tests UI test cleanup: Extract for_kv_map lint tests Fix test for #57250 Limit infinite_iter collect() check to known types Some improvements to util documentation Use hashset for name blacklist Reformat random_state tests Use node_id_to_type_opt instead of node_it_to_type in random_state Check pattern equality while checking declaration equality random_state lint Use an FxHashSet for valid idents in documentation lint Fix suggestion for unnecessary_ref lint Update CONTRIBUTING.md for rustfix tests Update .fixed files via update-references.sh Run rustfix on first UI test Use WIP branch for compiletest_rs ```` Also updates RLS and removes the patching of rustc_tool_utils from cargo.toml RLS changes: ```` update clippy hash and rustc_tools_util and use rustc_tools_util from crates.io Work around #55937 Update Clippy... again Update Clippy Update clippy ```` r? @oli-obk

This commit fixes a bug introduced by rust-lang#55937 which started checking user type annotations for associated type patterns. Where lowering a associated constant expression would previously return a `PatternKind::Constant`, it now returns a `PatternKind::AscribeUserType` with a `PatternKind::Constant` inside, this commit unwraps that to access the constant pattern inside and behaves as before.

@pnkfelix

Lower constant patterns with ascribed types. Fixes #57960. This PR fixes a bug introduced by #55937 which started checking user type annotations for associated type patterns. Where lowering a associated constant expression would previously return a `PatternKind::Constant`, it now returns a `PatternKind::AscribeUserType` with a `PatternKind::Constant` inside, this PR unwraps that to access the constant pattern inside and behaves as before. r? @pnkfelix

This commit fixes a bug introduced by rust-lang#55937 which started checking user type annotations for associated type patterns. Where lowering a associated constant expression would previously return a `PatternKind::Constant`, it now returns a `PatternKind::AscribeUserType` with a `PatternKind::Constant` inside, this commit unwraps that to access the constant pattern inside and behaves as before.

rust-highfive assigned nikomatsakis Nov 13, 2018

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Nov 13, 2018