Suggest use if import, using, or require is used instead

[bindsdev]

I was looking at namely issue #99751 when I thought about this. If work is being put into improving error messages when somebody uses a keyword that defines a function in another language, there should also be improved error messages if someone uses the incorrect directive to bring something into the scope of their module or namespace/

Given the following code: Playground Link

import std::mem;
using std::mem;
require std::mem;

The current output is:

error: expected one of `!` or `::`, found `std`
 --> src/main.rs:1:8
  |
1 | import std::mem;
  |        ^^^ expected one of `!` or `::`

error: could not compile `playground` due to previous error

The error message should preferably suggest the user to use the use directive to bring something into scope of their module.

[gimbling-away]

@rustbot claim

[compiler-errors]

For the record, on nightly, both import and using suggest using use. I'm sure it's not that difficult to add require.

[bindsdev]

For the record, on nightly, both import and using suggest using use. I'm sure it's not that difficult to add require.

ah. I was not aware of this. Less work to do then!

[gimbling-away]

[Ignore this, just notes]

rust/compiler/rustc_parse/src/parser/item.rs

Line 274 in caee496

&& (self.token.is_ident_named(sym::import) || self.token.is_ident_named(sym::using))

rust/compiler/rustc_span/src/symbol.rs

Line 1172 in 6f18f0a

repr_transparent,

[chenyukang]

@gimbles
And also add include?
Rust may go tooooo friendly in diagnostic message 😊.
Do you mind that I make a PR for it? I'm a newbie in hacking Rust compiler.

[gimbling-away]

Sure! The earlier message should clarify where the edits are needed to be made. Ain't nothing as a diagnostic too friendly. =)

[gimbling-away]

@chenyukang Remember to assign yourself using rustbot. 😄

Just a note for the future, usually if someone has already claimed an issue, it's not exactly common for someone else to fix it [aside from if the issue is abandoned by the claimee].

Since you're a newcomer here, I removed my assignment (and because I was working on another). However, you can find loads of easy issues with the E-Easy and/or E-Mentor tag for gaining experience.

A few resources that might be helpful ->
https://github.com/rust-lang/triagebot/wiki
https://github.com/rust-lang/rustc-dev-guide

Have fun hacking on Rust! 🦀 🤎

[chenyukang]

@rustbot claim

[bindsdev]

@gimbles And also add include? Rust may go tooooo friendly in diagnostic message 😊. Do you mind that I make a PR for it? I'm a newbie in hacking Rust compiler.

Totally forgot about include! Good catch!