Wrong needless_return suggestion with blocks

[lnicola]

Clippy suggests changing return { e } + 10; to { x } + 10 instead of ({ x }) + 10 or ({ x } + 10), and that doesn't compile.

I'm not sure what it should do, always parenthesise the inner span? rustfmt doesn't fix that, and it would be a bit ugly. Should it recurse into the expression to see if there are any blocks?

[oli-obk]

huh? this feels more like a rustc bug that it doesn't accept { x } + y as a trailing return expression

[lnicola]

Apparently, the block is a statement, not an expression. I wasn't aware of the difference until running into this.

[birkenfeld]

It's good that this is a compile error, consider - instead of +:

fn x() -> i32 {
    { 1 } - 1
}

fn y() -> i32 {
    { 1 }
    -1
}

Does it return 0 or -1?

[steffahn]

So the right thing to suggest here would be to remove the return but add parentheses.

[GnomedDev]

Seems to be fixed, ({ e } + 10) is the emitted suggestion nowadays which does compile.