Compiler import suggestions are not useful

The combination of the large amount of crates loaded by default on the playground and Rust 2018 no longer requiring extern crate has created a usability problem.

Consider the following code:

fn main() {
    let _: Error;
}

This will result in this compile error:

error[E0412]: cannot find type `Error` in this scope
 --> src/main.rs:2:12
  |
2 |     let _: Error;
  |            ^^^^^ not found in this scope
help: possible candidates are found in other modules, you can import them into scope
  |
1 | use cc::Error;
  |
1 | use clap::Error;
  |
1 | use core::fmt::Error;
  |
1 | use csv::Error;
  |
and 53 other candidates

Previously, it would've only shown suggestions from std, which is probably what I wanted. I don't know how this could be reasonably fixed.

Reproduce the Rust 2018 example in the Playground with its default crates and inspect how compiler import suggestions are produced. Determine whether the fix belongs in the Playground setup or suggestion behavior; done means common unresolved names produce useful, focused candidates instead of a long list of unrelated crates.