Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Misleading unreachable code warning from return in try blocks #54165

Closed
scottmcm opened this issue Sep 12, 2018 · 0 comments · Fixed by #64581
Closed

Misleading unreachable code warning from return in try blocks #54165

scottmcm opened this issue Sep 12, 2018 · 0 comments · Fixed by #64581
Labels
A-lint Area: Lints (warnings about flaws in source code) such as unused_mut. C-bug Category: This is a bug. F-try_blocks `#![feature(try_blocks)]` requires-nightly This issue requires a nightly compiler in some way. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

Comments

@scottmcm
Copy link
Member

#![feature(try_blocks)]

fn first_some() -> Option<()> {
    let _: Option<_> = try { return Some(foo()?) };
    let _: Option<_> = try { return Some(bar()?) };
    None
}

https://play.rust-lang.org/?gist=363157c898e0d067260e711db131b256&version=nightly&edition=2018

warning: unreachable expression
 --> src/main.rs:4:30
  |
4 |     let _: Option<_> = try { return Some(foo()?) };
  |                              ^^^^^^^^^^^^^^^^^^^
  |
  = note: #[warn(unreachable_code)] on by default

warning: unreachable expression
 --> src/main.rs:5:30
  |
5 |     let _: Option<_> = try { return Some(bar()?) };
  |                              ^^^^^^^^^^^^^^^^^^^

The desugar should probably just suppress this warning for the code it generates.

@zackmdavis zackmdavis added the A-lint Area: Lints (warnings about flaws in source code) such as unused_mut. label Sep 13, 2018
@jonas-schievink jonas-schievink added C-bug Category: This is a bug. F-try_blocks `#![feature(try_blocks)]` T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. requires-nightly This issue requires a nightly compiler in some way. labels Aug 6, 2019
Centril added a commit to Centril/rust that referenced this issue Oct 1, 2019
…ode, r=Centril

Fix unreachable_code warnings for try{} block ok-wrapped expressions

Fixes rust-lang#54165 and fixes rust-lang#63324.
@bors bors closed this as completed in 18d0c03 Oct 2, 2019
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
A-lint Area: Lints (warnings about flaws in source code) such as unused_mut. C-bug Category: This is a bug. F-try_blocks `#![feature(try_blocks)]` requires-nightly This issue requires a nightly compiler in some way. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
Projects
None yet
Development

Successfully merging a pull request may close this issue.

3 participants