Code
#![feature(adt_const_params, min_generic_const_args)]
const fn bar() -> [u64; 1] {
[42]
}
struct Foo<const P: [u64; 1]>(());
fn main() {
let _ = Foo::<{ bar() }>;
}Current output
error: tuple constructor with invalid base path
--> src/main.rs:10:21
|
10 | let _ = Foo::<{ bar() }>;
| ^^^Desired output
error: complex const arguments must be placed inside of a `const` block
--> src/main.rs:10:19
|
10 | let _ = Foo::<{ bar() }>;
| ^^^^^^^^^Rationale and extra context
#150603 changed the helpful error message complex const arguments must be placed inside of a const block to the less helpful tuple constructor with invalid base path for this code.
Other cases
Rust Version
# First version this issue started occurring on
$ rustc --version --verbose
rustc 1.94.0-nightly (4fa80a5e7 2026-01-05)
binary: rustc
commit-hash: 4fa80a5e733e2202d7ca4c203c2fdfda41cfe7dc
commit-date: 2026-01-05
host: x86_64-unknown-linux-gnu
release: 1.94.0-nightly
LLVM version: 21.1.8
Anything else?
No response
Code
Current output
Desired output
Rationale and extra context
#150603 changed the helpful error message
complex const arguments must be placed inside of aconstblockto the less helpfultuple constructor with invalid base pathfor this code.Other cases
Rust Version
# First version this issue started occurring on $ rustc --version --verbose rustc 1.94.0-nightly (4fa80a5e7 2026-01-05) binary: rustc commit-hash: 4fa80a5e733e2202d7ca4c203c2fdfda41cfe7dc commit-date: 2026-01-05 host: x86_64-unknown-linux-gnu release: 1.94.0-nightly LLVM version: 21.1.8Anything else?
No response