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Matthias Krüger 709baaef13
Rollup merge of #126893 - dtolnay:prec, r=compiler-errors 
Eliminate the distinction between PREC_POSTFIX and PREC_PAREN precedence level

I have been tangling with precedence as part of porting some pretty-printer improvements from syn back to rustc (related to parenthesization of closures, returns, and breaks by the AST pretty-printer).

As far as I have been able to tell, there is no difference between the 2 different precedence levels that rustc identifies as `PREC_POSTFIX` (field access, square bracket index, question mark, method call) and `PREC_PAREN` (loops, if, paths, literals).

There are a bunch of places that look at either `prec < PREC_POSTFIX` or `prec >= PREC_POSTFIX`. But there is nothing that needs to distinguish PREC_POSTFIX and PREC_PAREN from one another.

d49994b060/compiler/rustc_ast/src/util/parser.rs (L236-L237)

d49994b060/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs (L2829)

d49994b060/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs (L1290)

In the interest of eliminating a distinction without a difference, this PR collapses these 2 levels down to 1.

There is exactly 1 case where an expression with PREC_POSTFIX precedence needs to be parenthesized in a location that an expression with PREC_PAREN would not, and that's when the receiver of ExprKind::MethodCall is ExprKind::Field. `x.f()` means a different thing than `(x.f)()`. But this does not justify having separate precedence levels because this special case in the grammar is not governed by precedence. Field access does not have "lower precedence than" method call syntax &mdash; you can tell because if it did, then `x.f[0].f()` wouldn't be able to have its unparenthesized field access in the receiver of a method call. Because this Field/MethodCall special case is not governed by precedence, it already requires special handling and is not affected by eliminating the PREC_POSTFIX precedence level.

d49994b060/compiler/rustc_ast_pretty/src/pprust/state/expr.rs (L217-L221)
2024-06-25 18:03:00 +02:00
.github make bors ignore comments in PR template 2024-06-14 21:52:25 +00:00
.reuse std: move Once implementations to sys 2024-03-12 15:41:06 +01:00
compiler Rollup merge of #126893 - dtolnay:prec, r=compiler-errors 2024-06-25 18:03:00 +02:00
library Auto merge of #126852 - scottmcm:more-checked-math-tweaks, r=Amanieu 2024-06-25 02:50:37 +00:00
LICENSES Add missing CC-BY-SA-4.0. 2023-11-27 11:03:53 +00:00
src Rollup merge of #126893 - dtolnay:prec, r=compiler-errors 2024-06-25 18:03:00 +02:00
tests Rollup merge of #126884 - estebank:issue-125634, r=Nadrieril 2024-06-25 18:03:00 +02:00
.editorconfig Only use max_line_length = 100 for *.rs 2023-07-10 15:18:36 -07:00
.git-blame-ignore-revs Ignore compiletest test directive migration commits 2024-02-22 18:55:02 +00:00
.gitattributes Rename config.toml.example to config.example.toml 2023-03-11 14:10:00 -08:00
.gitignore Add /rustc-ice*/ to .gitignore` 2024-06-17 23:00:33 -05:00
.gitmodules refactor: add rustc-perf submodule to src/tools 2024-05-20 14:56:49 +00:00
.mailmap .mailmap: Associate both my work and my private email with me 2024-06-15 09:27:39 +02:00
Cargo.lock Rollup merge of #126845 - rust-lang:cargo_update, r=Mark-Simulacrum 2024-06-24 06:27:15 +02:00
Cargo.toml chore: bump version 2024-06-21 18:20:47 -05:00
CODE_OF_CONDUCT.md Remove the code of conduct; instead link https://www.rust-lang.org/conduct.html 2019-10-05 22:55:19 +02:00
config.example.toml Remove src/tools/rust-demangler 2024-06-19 20:41:34 +10:00
configure Ensure ./configure works when configure.py path contains spaces 2024-02-16 18:57:22 +00:00
CONTRIBUTING.md fix: Update CONTRIBUTING.md recommend -> recommended 2023-11-16 23:57:09 +05:30
COPYRIGHT Update COPYRIGHT file 2022-10-30 10:23:14 -04:00
INSTALL.md chore: fix some comments 2024-03-27 22:32:53 +08:00
LICENSE-APACHE Remove appendix from LICENCE-APACHE 2019-12-30 14:25:53 +00:00
LICENSE-MIT LICENSE-MIT: Remove inaccurate (misattributed) copyright notice 2017-07-26 16:51:58 -07:00
README.md Use SVG logos in the README.md. 2024-04-03 19:48:20 +02:00
RELEASES.md Rollup merge of #126250 - epage:change, r=Mark-Simulacrum 2024-06-17 04:53:55 +01:00
rust-bors.toml Increase timeout for new bors bot 2024-03-13 08:31:07 +01:00
rustfmt.toml Explain why tests/ui-fulldeps/ is unformatted. 2024-06-04 14:15:45 +10:00
triagebot.toml Rollup merge of #126909 - onur-ozkan:add-kobzol, r=matthiaskrgr 2024-06-24 15:51:05 -04:00
x Make x capable of resolving symlinks 2023-10-14 17:53:33 +03:00
x.ps1 use & instead of start-process in x.ps1 2023-12-09 09:46:16 -05:00
x.py Fix recent python linting errors 2023-08-02 04:40:28 -04:00

README.md

This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.

Why Rust?

  • Performance: Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrate with other languages.

  • Reliability: Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.

  • Productivity: Comprehensive documentation, a compiler committed to providing great diagnostics, and advanced tooling including package manager and build tool (Cargo), auto-formatter (rustfmt), linter (Clippy) and editor support (rust-analyzer).

Quick Start

Read "Installation" from The Book.

Installing from Source

If you really want to install from source (though this is not recommended), see INSTALL.md.

Getting Help

See https://www.rust-lang.org/community for a list of chat platforms and forums.

Contributing

See CONTRIBUTING.md.

License

Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.

See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.

Trademark

The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the "Rust Trademarks").

If you want to use these names or brands, please read the media guide.

Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.