rust/tests/ui/pattern/issue-115599.rs

const CONST_STRING: String = String::new();

fn main() {
    let empty_str = String::from("");
    if let CONST_STRING = empty_str {}
    //~^ ERROR constant of non-structural type `Vec<u8>` in a pattern
}
use `PatKind::error` when an ADT const value has violation 2023-10-15 19:20:06 +08:00			`const CONST_STRING: String = String::new();`

			`fn main() {`
			`let empty_str = String::from("");`
			`if let CONST_STRING = empty_str {}`
Add additional context for non-sructural type constant used in pattern - Point at type that should derive `PartialEq` to be structural. - Point at manual `impl PartialEq`, explaining that it is not sufficient to be structural. ``` error: constant of non-structural type `MyType` in a pattern --> $DIR/const-partial_eq-fallback-ice.rs:14:12 \| LL \| struct MyType; \| ------------- `MyType` must be annotated with `#[derive(PartialEq)]` to be usable in patterns ... LL \| const CONSTANT: &&MyType = &&MyType; \| ------------------------ constant defined here ... LL \| if let CONSTANT = &&MyType { \| ^^^^^^^^ constant of non-structural type \| note: the `PartialEq` trait must be derived, manual `impl`s are not sufficient; see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details --> $DIR/const-partial_eq-fallback-ice.rs:5:1 \| LL \| impl PartialEq<usize> for MyType { \| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ``` 2024-11-20 04:30:35 +00:00			//~^ ERROR constant of non-structural type `Vec<u8>` in a pattern
use `PatKind::error` when an ADT const value has violation 2023-10-15 19:20:06 +08:00			`}`