macro-error for macros from external crates with rust-analyzer 1.94.0 #21224
Description
Similar/related issue? #21216
Context
Both rust-analyzer versions produce the error.
| version | |
|---|---|
| rust-analyzer | 0.3.2702-standalone (d646b23f00 2025-11-30) |
0.4.2708-standalone (2cbf3587d3 2025-12-05) |
|
| rustc | 1.94.0-nightly (ba86c0460 2025-12-06) |
editor: VSCode 1.106.3
relevant settings: Default extension settings.
Problem reproduction
code snippet to reproduce:
// tests/test.rs
use test_case::test_case;
#[test_case(10, 10 ; "test")]
fn it_works(input: i32, expected: i32) {
assert_eq!(input, expected);
}Expected behaviour: rust-analyzer doesn't show any errors.
Actual behaviour: rust-analyzer shows macro-error for the test_case macro:
failed to write request: The length of a sequence must be known
The problem seemed to occur for all macros that come from other crates as using parametrized or rstest instead of test_case didn't work either.
Workaround
Using stable rustc (1.91.1 (ed61e7d7e 2025-11-07)) for rust-analyzer makes the problem disappear:
"rust-analyzer.server.extraEnv": {
"RUSTUP_TOOLCHAIN": "stable"
}