False positive unused_import warning on std::string::String #71450
Closed
Description
This (very contrived) example emits a warning:
mod foo {
pub struct String;
#[derive(Debug)]
pub struct Number;
}
fn main() {
use std::string::String;
use foo::*;
let n = Number;
let s = String::new();
println!("{:?} {}", n, s);
}Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=4333aa0dec7b94c3d2942e7380894003
warning: the item `String` is imported redundantly
--> src/main.rs:9:9
|
9 | use std::string::String;
| ^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(unused_imports)]` on by default
This is a false positive because removing use std::string::String results in a compilation error:
error[E0599]: no function or associated item named `new` found for struct `foo::String` in the current scope
--> src/main.rs:13:21
|
2 | pub struct String;
| ------------------ function or associated item `new` not found for this
...
13 | let s = String::new();
| ^^^ function or associated item not found in `foo::String`
Meta
$ rustc --version --verbose
rustc 1.42.0 (b8cedc004 2020-03-09)
binary: rustc
commit-hash: b8cedc00407a4c56a3bda1ed605c6fc166655447
commit-date: 2020-03-09
host: x86_64-pc-windows-msvc
release: 1.42.0
LLVM version: 9.0
Same for 1.43.0-beta.6 and 1.44.0-nightly (2020-04-21 45d050cde277b22a7558).
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