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

Remove trailing semicolons from several macro definitions #938

Merged
merged 1 commit into from
Nov 2, 2020

Conversation

Aaron1011
Copy link
Member

The x86 code contains several macros that following this pattern:

macro_rules! expr {
    () => { true; }
}

fn bar(_val: bool) {}

fn main() {
    bar(expr!());
}

Here, we have a macro expr! that expands to tokens sequence with
a trailing semicolon.

Currently, the trailing semicolon is ignored when the macro is invoked
in expression position, due to rust-lang/rust#33953
If this behavior is changed, then a large number of macro invocations in
stdarch will stop compiling.

Regardless of whether nor not this change is made, removing the
semicolon more clearly expresses the intent of the code - these macros
are designed to expand to the result of a function call, not ignore its
results (as the ; would suggest).

@rust-highfive
Copy link

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @Amanieu (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

The x86 code contains several macros that following this pattern:

```rust
macro_rules! expr {
    () => { true; }
}

fn bar(_val: bool) {}

fn main() {
    bar(expr!());
}
```

Here, we have a macro `expr!` that expands to tokens sequence with
a trailing semicolon.

Currently, the trailing semicolon is ignored when the macro is invoked
in expression position, due to rust-lang/rust#33953
If this behavior is changed, then a large number of macro invocations in
`stdarch` will stop compiling.

Regardless of whether nor not this change is made, removing the
semicolon more clearly expresses the intent of the code - these macros
are designed to expand to the result of a function call, not ignore its
results (as the `;` would suggest).
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

3 participants