Better error message when forgetting the right operand in an if condition

[antoyo]

Hello.
The following code gives an error message that could be improved:

fn main() {
    let n = 1;
    if 5 == {
        println!("five");
    }
}

It gives the following error:

src/main.rs:6:1: 6:2 error: expected `{`, found `}`
src/main.rs:6 }
              ^
src/main.rs:6:1: 6:2 help: place this code inside a block

This is because the compiler sees the right operand as a block expression, and is looking for the condition body, something like:

fn main() {
    let n = 1;
    if 5 == {
        println!("five");
        5
    } {
        println!("Five");
    }
}

while we most probably mean to write something like:

fn main() {
    let n = 1;
    if 5 == n {
        println!("five");
    }
}

So, it would be nice to improve this error message.

[nagisa]

This… would be pretty non-trivial to improve. What really bugs me is help being pretty useless, which for I’m going to fill another issue.

[antoyo]

As of today, I still get the same issue:

error: expected `{`, found `}`
 --> src/main.rs:8:1
  |
6 |     if true == {
  |     -- this `if` statement has a condition, but no block
7 |     }
8 | }
  | ^

[estebank]

FWIW, the originally reported output was:

error: expected `{`, found `}`
 --> src/main.rs:8:1
  |
8 | }
  | ^