Recover `mut $pat` and other improvements #63945

Centril · 2019-08-27T11:12:46Z

Recover on e.g. mut Foo(x, y) and suggest Foo(mut x, mut y). Fixes Custom diagnostic for bad mut in pattern with sub-bindings #63764.
Recover on e.g. let mut mut x;
Recover on e.g. let keyword and let keyword(...).
Cleanups in token.rs with fn is_non_raw_ident_where and friends.

rust-highfive · 2019-08-27T11:12:51Z

r? @eddyb

(rust_highfive has picked a reviewer for you, use r? to override)

Centril · 2019-08-27T11:12:57Z

r? @estebank

src/libsyntax/parse/parser/pat.rs

Centril · 2019-08-27T17:56:09Z

This turned out to add quite a bit of additional logic but I think it's a working implementation.
cc also @petrochenkov

Centril · 2019-08-27T18:00:12Z

src/libsyntax/parse/parser/pat.rs

+        AddMut.visit_pat(&mut pat);
+
+        // Unwrap; If we don't have `mut $ident`, error.
+        let pat = pat.into_inner();


We could avoid this allocation by extracting a new function fn parse_pat_with_range_pat_kind. This would also avoid the need for the NtPat logic above but it would also not recover on let mut $p where $p:pat.

src/test/ui/parser/issue-32501.stderr

estebank · 2019-08-27T18:55:06Z

src/test/ui/parser/keyword-pub-as-identifier.rs

@@ -1,5 +1,5 @@
 // This file was auto-generated using 'src/etc/generate-keyword-tests.py pub'

 fn main() {
-    let pub = "foo"; //~ error: expected pattern, found keyword `pub`
+    let pub = "foo"; //~ error: expected identifier, found keyword `pub`


I think all of these tests could be one file, don't you think? (not to be addressed in this PR necessarily)

Want to file a follow up issue?

src/test/ui/self/self_type_keyword.stderr

src/test/ui/self/self_type_keyword.rs

estebank · 2019-08-27T19:03:21Z

src/libsyntax/parse/parser/pat.rs

+        self.check_path()
+        // Just for recovery (see `can_be_ident`).
+        || self.token.is_ident() && !self.token.is_bool_lit() && !self.token.is_keyword(kw::In)
+    }


Looking at this made me realize that we should have some check for "expected Fn() -> _, found bool and expr is foo\n|| bar" to detect a missing ; on the first pattern and returning a closure was intended 😬

What would be a concrete example of a pitfall here? I'd like to avoid complicating things until someone reports a an issue.

src/libsyntax/parse/parser/pat.rs

estebank

LGTM, but I'd like to handle the _ and Self cases as well to avoid being misleading (don't add or change the suggestion in those two cases). r=me

Centril · 2019-08-27T21:54:47Z

@estebank I made some more changes; can you have another quick look at the code?

estebank · 2019-08-27T21:55:04Z

@bors r+

bors · 2019-08-27T21:55:08Z

📌 Commit 42e895d has been approved by estebank

Recover `mut $pat` and other improvements - Recover on e.g. `mut Foo(x, y)` and suggest `Foo(mut x, mut y)`. Fixes rust-lang#63764. - Recover on e.g. `let mut mut x;` - Recover on e.g. `let keyword` and `let keyword(...)`. - Cleanups in `token.rs` with `fn is_non_raw_ident_where` and friends.

@ghost

Rollup of 11 pull requests Successful merges: - #63811 (Correctly suggest adding bounds to `impl Trait` argument) - #63933 (Resolve some small issues related to #63580) - #63938 (or-pattern: fix typo in error message) - #63945 (Recover `mut $pat` and other improvements) - #63958 (const_prop: only call error_to_const_error if we are actually showing something) - #63961 (Add Option<Span> to `require_lang_item`) - #63963 (remove the reference to __cxa_thread_atexit_impl) - #63965 (Prevent syntax error in LD linker version script) - #63968 (rustc_apfloat: make the crate #![no_std] explicitly.) - #63970 (Notify me (flip1995) when Clippy toolstate changes) - #63980 (add missing `#[repr(C)]` on the Slices union) Failed merges: - #63989 (Add Yaah to clippy toolstain notification list) r? @ghost

Pkgsrc changes: * Remove patch which no longer applies (but what about RPATH?) * Adapt a few patches to changed files upstream. Upstream changes: Version 1.39.0 (2019-11-07) =========================== Language -------- - [You can now create `async` functions and blocks with `async fn`, `async move {}`, and `async {}` respectively, and you can now call `.await` on async expressions.][63209] - [You can now use certain attributes on function, closure, and function pointer parameters.][64010] These attributes include `cfg`, `cfg_attr`, `allow`, `warn`, `deny`, `forbid` as well as inert helper attributes used by procedural macro attributes applied to items. e.g. ```rust fn len( #[cfg(windows)] slice: &[u16], #[cfg(not(windows))] slice: &[u8], ) -> usize { slice.len() } ``` - [You can now take shared references to bind-by-move patterns in the `if` guards of `match` arms.][63118] e.g. ```rust fn main() { let array: Box<[u8; 4]> = Box::new([1, 2, 3, 4]); match array { nums // ---- `nums` is bound by move. if nums.iter().sum::<u8>() == 10 // ^------ `.iter()` implicitly takes a reference to `nums`. => { drop(nums); // ----------- Legal as `nums` was bound by move and so we have ownership. } _ => unreachable!(), } } ``` Compiler -------- - [Added tier 3\* support for the `i686-unknown-uefi` target.][64334] - [Added tier 3 support for the `sparc64-unknown-openbsd` target.][63595] - [rustc will now trim code snippets in diagnostics to fit in your terminal.] [63402] **Note** Cargo currently doesn't use this feature. Refer to [cargo#7315][cargo/7315] to track this feature's progress. - [You can now pass `--show-output` argument to test binaries to print the output of successful tests.][62600] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`Vec::new` and `String::new` are now `const` functions.][64028] - [`LinkedList::new` is now a `const` function.][63684] - [`str::len`, `[T]::len` and `str::as_bytes` are now `const` functions.][63770] - [The `abs`, `wrapping_abs`, and `overflowing_abs` numeric functions are now `const`.][63786] Stabilized APIs --------------- - [`Pin::into_inner`] - [`Instant::checked_duration_since`] - [`Instant::saturating_duration_since`] Cargo ----- - [You can now publish git dependencies if supplied with a `version`.] [cargo/7237] - [The `--all` flag has been renamed to `--workspace`.][cargo/7241] Using `--all` is now deprecated. Misc ---- - [You can now pass `-Clinker` to rustdoc to control the linker used for compiling doctests.][63834] Compatibility Notes ------------------- - [Code that was previously accepted by the old borrow checker, but rejected by the NLL borrow checker is now a hard error in Rust 2018.][63565] This was previously a warning, and will also become a hard error in the Rust 2015 edition in the 1.40.0 release. - [`rustdoc` now requires `rustc` to be installed and in the same directory to run tests.][63827] This should improve performance when running a large amount of doctests. - [The `try!` macro will now issue a deprecation warning.][62672] It is recommended to use the `?` operator instead. - [`asinh(-0.0)` now correctly returns `-0.0`.][63698] Previously this returned `0.0`. [62600]: rust-lang/rust#62600 [62672]: rust-lang/rust#62672 [63118]: rust-lang/rust#63118 [63209]: rust-lang/rust#63209 [63402]: rust-lang/rust#63402 [63565]: rust-lang/rust#63565 [63595]: rust-lang/rust#63595 [63684]: rust-lang/rust#63684 [63698]: rust-lang/rust#63698 [63770]: rust-lang/rust#63770 [63786]: rust-lang/rust#63786 [63827]: rust-lang/rust#63827 [63834]: rust-lang/rust#63834 [63927]: rust-lang/rust#63927 [63933]: rust-lang/rust#63933 [63934]: rust-lang/rust#63934 [63938]: rust-lang/rust#63938 [63940]: rust-lang/rust#63940 [63941]: rust-lang/rust#63941 [63945]: rust-lang/rust#63945 [64010]: rust-lang/rust#64010 [64028]: rust-lang/rust#64028 [64334]: rust-lang/rust#64334 [cargo/7237]: rust-lang/cargo#7237 [cargo/7241]: rust-lang/cargo#7241 [cargo/7315]: rust-lang/cargo#7315 [`Pin::into_inner`]: https://doc.rust-lang.org/std/pin/struct.Pin.html#method.into_inner [`Instant::checked_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_duration_since [`Instant::saturating_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.saturating_duration_since

@matthewjasper

…stebank parse: recover `mut (x @ y)` as `(mut x @ mut y)`. Follow up to rust-lang#68992 (comment) and rust-lang#63945. Specifically, when given `let mut (x @ y)` we recover with `let (mut x @ mut y)` as the suggestion: ```rust error: `mut` must be attached to each individual binding --> $DIR/mut-patterns.rs:12:9 | LL | let mut (x @ y) = 0; | ^^^^^^^^^^^ help: add `mut` to each binding: `(mut x @ mut y)` | = note: `mut` may be followed by `variable` and `variable @ pattern` ``` r? @matthewjasper @estebank

Centril added 3 commits August 27, 2019 10:14

token: refactor with is_non_raw_ident_where.

5cc1559

Simplify with Symbol/Token::is_book_lit.

e49b958

recover on 'mut ' and improve recovery for keywords.

f908aa9

rust-highfive assigned eddyb Aug 27, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Aug 27, 2019

rust-highfive assigned estebank and unassigned eddyb Aug 27, 2019

Centril commented Aug 27, 2019

View reviewed changes

src/libsyntax/parse/parser/pat.rs Show resolved Hide resolved

Centril changed the title ~~Recover mut $pat and other improvements~~ [WIP] Recover mut $pat and other improvements Aug 27, 2019

Ensure 'let mut ;' where ':pat' is banned.

dbbe336

Centril changed the title ~~[WIP] Recover mut $pat and other improvements~~ Recover mut $pat and other improvements Aug 27, 2019

Centril commented Aug 27, 2019

View reviewed changes

estebank reviewed Aug 27, 2019

View reviewed changes

src/test/ui/parser/issue-32501.stderr Outdated Show resolved Hide resolved

estebank reviewed Aug 27, 2019

View reviewed changes

src/test/ui/self/self_type_keyword.stderr Outdated Show resolved Hide resolved

estebank reviewed Aug 27, 2019

View reviewed changes

src/test/ui/self/self_type_keyword.rs Show resolved Hide resolved

estebank reviewed Aug 27, 2019

View reviewed changes

src/libsyntax/parse/parser/pat.rs Show resolved Hide resolved

estebank approved these changes Aug 27, 2019

View reviewed changes

Improve 'mut ' diagnostic.

42e895d

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 Aug 27, 2019

Centril mentioned this pull request Aug 29, 2019

Rollup of 11 pull requests #63990

Merged

bors merged commit 42e895d into rust-lang:master Aug 29, 2019

Centril deleted the recover-mut-pat branch August 29, 2019 08:48

Centril mentioned this pull request Sep 28, 2019

RFC: mut (x, y, ..) and mut [x, y, ..] pattern shorthand rust-lang/rfcs#2401

Closed

Centril mentioned this pull request Feb 17, 2020

parse: recover mut (x @ y) as (mut x @ mut y). #69236

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Recover `mut $pat` and other improvements #63945

Recover `mut $pat` and other improvements #63945

Centril commented Aug 27, 2019 •

edited

Loading

rust-highfive commented Aug 27, 2019

Centril commented Aug 27, 2019

Centril commented Aug 27, 2019

Centril Aug 27, 2019

estebank Aug 27, 2019

Centril Aug 27, 2019

estebank Aug 27, 2019

Centril Aug 27, 2019

estebank left a comment •

edited

Loading

Centril commented Aug 27, 2019

estebank commented Aug 27, 2019

bors commented Aug 27, 2019

Recover mut $pat and other improvements #63945

Recover mut $pat and other improvements #63945

Conversation

Centril commented Aug 27, 2019 • edited Loading

rust-highfive commented Aug 27, 2019

Centril commented Aug 27, 2019

Centril commented Aug 27, 2019

Centril Aug 27, 2019

Choose a reason for hiding this comment

estebank Aug 27, 2019

Choose a reason for hiding this comment

Centril Aug 27, 2019

Choose a reason for hiding this comment

estebank Aug 27, 2019

Choose a reason for hiding this comment

Centril Aug 27, 2019

Choose a reason for hiding this comment

estebank left a comment • edited Loading

Choose a reason for hiding this comment

Centril commented Aug 27, 2019

estebank commented Aug 27, 2019

bors commented Aug 27, 2019

Recover `mut $pat` and other improvements #63945

Recover `mut $pat` and other improvements #63945

Centril commented Aug 27, 2019 •

edited

Loading

estebank left a comment •

edited

Loading