`assert_is_empty` suggestion missing type annotations

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#17,676 7 comments 0 reactions 1 assignee View on GitHub

@ABHINAB-CHHETRI is already working on this.

Since Sep 3, 2026.

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Description

C-bug I-suggestion-causes-error
Summary

assert_is_empty suggests [] as a replacement, but the resulting code can fail to compile because the array element type cannot be inferred.

Reproducer

Code:

pub fn issue17676(v: &[&str]) {
    assert!(v.is_empty());
}

Current output:

pub fn issue17676(v: &[&str]) {
    assert_eq!(v, []);
}

error[E0282]: type annotations needed
 --> <source>:2:5
  |
2 |     assert_eq!(v, []);
  |     ^^^^^^^^^^^^^^^^^ cannot infer type

Desired output:

pub fn f(v: &[&str]) {
    assert_eq!(v, [""; 0]);
}

https://rust.godbolt.org/z/eG4MTGK5n

Version
clippy 0.1.100 (5db7f4be8a 2026-09-01)
Dominant language
Rust
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