rust/tests/ui/pattern/rest-pat-semantic-disallowed.rs
2023-01-11 09:32:08 +00:00

83 lines
2.4 KiB
Rust

// Here we test that rest patterns, i.e. `..`, are not allowed
// outside of slice (+ ident patterns within those), tuple,
// and tuple struct patterns and that duplicates are caught in these contexts.
#![feature(box_patterns)]
fn main() {}
macro_rules! mk_pat {
() => { .. } //~ ERROR `..` patterns are not allowed here
}
fn rest_patterns() {
let mk_pat!();
// Top level:
fn foo(..: u8) {} //~ ERROR `..` patterns are not allowed here
let ..; //~ ERROR `..` patterns are not allowed here
// Box patterns:
let box ..; //~ ERROR `..` patterns are not allowed here
// In or-patterns:
match 1 {
1 | .. => {} //~ ERROR `..` patterns are not allowed here
}
// Ref patterns:
let &..; //~ ERROR `..` patterns are not allowed here
let &mut ..; //~ ERROR `..` patterns are not allowed here
// Ident patterns:
let x @ ..; //~ ERROR `..` patterns are not allowed here
//~^ ERROR type annotations needed
let ref x @ ..; //~ ERROR `..` patterns are not allowed here
let ref mut x @ ..; //~ ERROR `..` patterns are not allowed here
// Tuple:
let (..): (u8,); // OK.
let (..,): (u8,); // OK.
let (
..,
.., //~ ERROR `..` can only be used once per tuple pattern
.. //~ ERROR `..` can only be used once per tuple pattern
): (u8, u8, u8);
let (
..,
x,
.. //~ ERROR `..` can only be used once per tuple pattern
): (u8, u8, u8);
struct A(u8, u8, u8);
// Tuple struct (same idea as for tuple patterns):
let A(..); // OK.
let A(..,); // OK.
let A(
..,
.., //~ ERROR `..` can only be used once per tuple struct pattern
.. //~ ERROR `..` can only be used once per tuple struct pattern
);
let A(
..,
x,
.. //~ ERROR `..` can only be used once per tuple struct pattern
);
// Array/Slice:
let [..]: &[u8]; // OK.
let [..,]: &[u8]; // OK.
let [
..,
.., //~ ERROR `..` can only be used once per slice pattern
.. //~ ERROR `..` can only be used once per slice pattern
]: &[u8];
let [
..,
ref x @ .., //~ ERROR `..` can only be used once per slice pattern
ref mut y @ .., //~ ERROR `..` can only be used once per slice pattern
(ref z @ ..), //~ ERROR `..` patterns are not allowed here
.. //~ ERROR `..` can only be used once per slice pattern
]: &[u8];
}