Rust errors / Patterns and matching
Rust compiler error · checked with rustc 1.99.0
Rust error E0532: expected unit struct, unit variant or constant, found tuple variant `State::Failed`
What it meansPattern arm did not match expected kind.
What rustc prints
error[E0532]: expected unit struct, unit variant or constant, found tuple variant `State::Failed`
--> main.rs:10:9
|
3 | Failed(String),
| -------------- `State::Failed` defined here
...
10 | State::Failed => println!("Failed"),
| ^^^^^^^^^^^^^ help: use the tuple variant pattern syntax instead: `State::Failed(_)`Real output of rustc 1.99.0 compiling the official example below (2021 edition). Your names and line numbers will differ; the first line is the part to match.
E0532Patterns and matching
Activein rustc 1.99.0
5related errors linked below
The compiler team's explanation
Pattern arm did not match expected kind.
Erroneous code example:
enum State {
Succeeded,
Failed(String),
}
fn print_on_failure(state: &State) {
match *state {
// error: expected unit struct, unit variant or constant, found tuple
// variant `State::Failed`
State::Failed => println!("Failed"),
_ => ()
}
}To fix this error, ensure the match arm kind is the same as the expression matched.
Fixed example:
enum State {
Succeeded,
Failed(String),
}
fn print_on_failure(state: &State) {
match *state {
State::Failed(ref msg) => println!("Failed with {}", msg),
_ => ()
}
}From rustc --explain E0532 (1.99.0), part of the Rust project, MIT or Apache-2.0. Official page.
Related errors
- E0004non-exhaustive patterns
- E0528pattern requires at least 3 elements but array has 2
- E0530match bindings cannot shadow tuple variants
- E0533expected unit struct, unit variant or constant, found associated function `Tortoise::turtle`
- E0638This error indicates that the struct, enum or enum variant must be matched non-exhaustively as it has been marked as `non_exhaustive`
Up next
Often hit nextE0004: non-exhaustive patternsA related error from the same family.Read it next →Did this answer your question?