Suggest import for E0433 Use of undeclared type or module

[alexheretic]

While E0412 already provides suggested imports, E0433 does not. It seems like a similar problem on the face of it. Can we add suggestions for undeclared type or module?

Particularly this helps IDEs working toward rust-lang/rls#742.

For example no suggestion is currently provided for the following.

pub fn main() {
    let set = HashSet::new();
}

error[E0433]: failed to resolve. Use of undeclared type or module `HashSet`
 --> src/main.rs:5:15
  |
5 |     let set = HashSet::new();
  |               ^^^^^^^ Use of undeclared type or module `HashSet`

{
  "children": [],
  "code": {
    "code": "E0433",
    "explanation": "\nAn undeclared type or module was used.\n\nErroneous code example:\n\n```compile_fail,E0433\nlet map = HashMap::new();\n// error: failed to resolve. Use of undeclared type or module `HashMap`\n```\n\nPlease verify you didn't misspell the type/module's name or that you didn't\nforgot to import it:\n\n\n```\nuse std::collections::HashMap; // HashMap has been imported.\nlet map: HashMap<u32, u32> = HashMap::new(); // So it can be used!\n```\n"
  },
  "level": "error",
  "message": "failed to resolve. Use of undeclared type or module `HashSet`",
  "rendered": "error[E0433]: failed to resolve. Use of undeclared type or module `HashSet`\n --> src/main.rs:2:15\n  |\n2 |     let set = HashSet::new();\n  |               ^^^^^^^ Use of undeclared type or module `HashSet`\n\nIf you want more information on this error, try using \"rustc --explain E0433\"\n",
  "spans": [{
    "byte_end": 37,
    "byte_start": 30,
    "column_end": 22,
    "column_start": 15,
    "expansion": null,
    "file_name": "src/main.rs",
    "is_primary": true,
    "label": "Use of undeclared type or module `HashSet`",
    "line_end": 2,
    "line_start": 2,
    "suggested_replacement": null,
    "text": [{
      "highlight_end": 22,
      "highlight_start": 15,
      "text": "    let set = HashSet::new();"
    }]
  }]
}

[TatriX]

Any progress on this? If not, how can I help?

[m-ysk]

@rustbot claim