rust/src/test/compile-fail/borrowck-loan-rcvr-overloaded-op.rs

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struct Point {
x: int,
y: int,
}
impl Point : ops::Add<int,int> {
pure fn add(&self, z: &int) -> int {
self.x + self.y + (*z)
}
}
impl Point {
fn times(z: int) -> int {
self.x * self.y * z
}
}
fn a() {
let mut p = Point {x: 3, y: 4};
// ok (we can loan out rcvr)
p + 3;
p.times(3);
}
fn b() {
let mut p = Point {x: 3, y: 4};
// Here I create an outstanding loan and check that we get conflicts:
let q = &mut p; //~ NOTE prior loan as mutable granted here
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p + 3; // ok for pure fns
p.times(3); //~ ERROR loan of mutable local variable as immutable conflicts with prior loan
q.x += 1;
}
fn c() {
// Here the receiver is in aliased memory and hence we cannot
// consider it immutable:
let q = @mut Point {x: 3, y: 4};
// ...this is ok for pure fns
*q + 3;
// ...but not impure fns
(*q).times(3); //~ ERROR illegal borrow unless pure
//~^ NOTE impure due to access to impure function
}
fn main() {
}