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// Test that a (partially) mutably borrowed place can be matched on, so long as
// we don't have to read any values that are mutably borrowed to determine
// which arm to take.
//
// Test that we don't allow mutating the value being matched on in a way that
// changes which patterns it matches, until we have chosen an arm.
struct A(i32, i32);
fn struct_example(mut a: A) {
let x = &mut a.0;
match a { // OK, no access of borrowed data
_ if false => (),
A(_, r) => (),
}
x;
}
fn indirect_struct_example(mut b: &mut A) {
let x = &mut b.0;
match *b { // OK, no access of borrowed data
_ if false => (),
A(_, r) => (),
}
x;
}
fn underscore_example(mut c: i32) {
let r = &mut c;
match c { // OK, no access of borrowed data (or any data at all)
_ if false => (),
_ => (),
}
r;
}
enum E {
V(i32, i32),
W,
}
fn enum_example(mut e: E) {
let x = match e {
E::V(ref mut x, _) => x,
E::W => panic!(),
};
match e { // Don't know that E uses a tag for its discriminant
//~^ ERROR
_ if false => (),
E::V(_, r) => (),
E::W => (),
}
x;
}
fn indirect_enum_example(mut f: &mut E) {
let x = match *f {
E::V(ref mut x, _) => x,
E::W => panic!(),
};
match f { // Don't know that E uses a tag for its discriminant
//~^ ERROR
_ if false => (),
E::V(_, r) => (),
E::W => (),
}
x;
}
fn match_on_muatbly_borrowed_ref(mut p: &bool) {
let r = &mut p;
match *p { // OK, no access at all
_ if false => (),
_ => (),
}
r;
}
fn match_on_borrowed(mut t: bool) {
let x = &mut t;
match t {
//~^ ERROR
true => (),
false => (),
}
x;
}
enum Never {}
fn never_init() {
let n: Never;
match n {} //~ ERROR
}
fn main() {}
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