"Insert explicit type" suggestion produces invalid code for array

[jplatte]

For arrays, ra produces an invalid suggestion to insert [T;_], where T is a concrete type, but _ is literally an underscore, which is not valid in that position.

Example:

let x = [0.0; 3];

produces a suggestion that when applied results in

let x: [f64;_] = [0.0; 3];

which leads to the error message

error: expected expression, found reserved identifier `_`
   --> src/file.rs:line:col
    |
col |             let x: [f64;_] = [0.0; 3];
    |                 -       ^ expected expression
    |                 |
    |                 while parsing the type for `x`

[lnicola]

Not that I disagree that this is a bug, but wasn't there an RFC to allow underscores for array lengths? It seems like a nice feature.

EDIT: rust-lang/rfcs#2545

[jplatte]

You were a bit faster than I was! ^^

But that RFC hasn't been merged yet, and apparently also hasn't been implemented, considering I get that error message on Nightly.