“help: place this code inside a block” is… pretty confusing

[nagisa]

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

reports

<anon>:6:1: 6:2 error: expected `{`, found `}`
<anon>:6 }
         ^
<anon>:6:1: 6:2 help: place this code inside a block

The help message is pretty confusing. Which code it has in mind? There’s no code which you could place into a block to fix this error either, as far as I can see.

[antoyo]

This help message makes sense with the following code:

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

because it needs curly braces for the body of the condition.

[Aatch]

One possible fix could be to attempt to parse an expression and only show the help message if it succeeded. So since } is not a valid expression, it won't work work. This would catch the case we want to, demonstrated by @antoyo, while hopefully avoiding the useless help message.

[estebank]

This ticket can be closed, given:

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

Diagnostics:

error: expected `{`, found `println`
 --> <anon>:4:9
  |
4 |         println!("five");
  |         ^^^^^^^
  |
help: try placing this code inside a block
  |         { println!("five") }

error: expected `{`, found `}`
  --> <anon>:11:1
   |
11 | }
   | ^

CC @jonathandturner

[sophiajt]

Definitely a bit better.

[antoyo]

Well, it does not seem to fix the issue in the first post.
It is the same error message, isn't it?

[sophiajt]

@antoyo - this one shows the code to put in the block

[antoyo]

What I meant is that the error from the first post:

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

reports

<anon>:6:1: 6:2 error: expected `{`, found `}`
<anon>:6 }
        ^
<anon>:6:1: 6:2 help: place this code inside a block

does not seem to have changed:

error: expected `{`, found `}`
 --> <anon>:11:1
   |
11 | }
   | ^

[sophiajt]

@antoyo - that part of the error is still correct, but there's an additional part now which gives more information:

error: expected `{`, found `println`
 --> <anon>:4:9
  |
4 |         println!("five");
  |         ^^^^^^^
  |
help: try placing this code inside a block
  |         { println!("five") }

[antoyo]

My understanding is that this error message is for the code in the second post:

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

But the code from the first post still gives the same error, right?

[estebank]

@antoyo #30035 is still open, this was a follow up only about the help: place this code inside a block message not being relevant.