rust/src/test/ui/parser/mut-patterns.rs

// Can't put mut in non-ident pattern

// edition:2018

#![feature(box_patterns)]
#![allow(warnings)]

pub fn main() {
    let mut mut x = 0;
    //~^ ERROR `mut` on a binding may not be repeated
    //~| remove the additional `mut`s

    struct Foo { x: isize }
    let mut Foo { x: x } = Foo { x: 3 };
    //~^ ERROR `mut` must be attached to each individual binding
    //~| add `mut` to each binding

    let mut Foo { x } = Foo { x: 3 };
    //~^ ERROR `mut` must be attached to each individual binding
    //~| add `mut` to each binding

    struct r#yield(u8, u8);
    let mut mut yield(become, await) = r#yield(0, 0);
    //~^ ERROR `mut` on a binding may not be repeated
    //~| ERROR `mut` must be attached to each individual binding
    //~| ERROR expected identifier, found reserved keyword `yield`
    //~| ERROR expected identifier, found reserved keyword `become`
    //~| ERROR expected identifier, found reserved keyword `await`

    struct W<T, U>(T, U);
    struct B { f: Box<u8> }
    let mut W(mut a, W(b, W(ref c, W(d, B { box f }))))
    //~^ ERROR `mut` must be attached to each individual binding
        = W(0, W(1, W(2, W(3, B { f: Box::new(4u8) }))));
}