61 lines
1.4 KiB
Rust
61 lines
1.4 KiB
Rust
type point = { x: int, y: int };
|
|
|
|
trait methods {
|
|
fn impurem();
|
|
fn blockm(f: fn());
|
|
pure fn purem();
|
|
}
|
|
|
|
impl foo of methods for point {
|
|
fn impurem() {
|
|
}
|
|
|
|
fn blockm(f: fn()) { f() }
|
|
|
|
pure fn purem() {
|
|
}
|
|
}
|
|
|
|
fn a() {
|
|
let mut p = {x: 3, y: 4};
|
|
|
|
// Here: it's ok to call even though receiver is mutable, because we
|
|
// can loan it out.
|
|
p.purem();
|
|
p.impurem();
|
|
|
|
// But in this case we do not honor the loan:
|
|
do p.blockm { //~ NOTE loan of mutable local variable granted here
|
|
p.x = 10; //~ ERROR assigning to mutable field prohibited due to outstanding loan
|
|
}
|
|
}
|
|
|
|
fn b() {
|
|
let mut p = {x: 3, y: 4};
|
|
|
|
// Here I create an outstanding loan and check that we get conflicts:
|
|
|
|
&mut p; //~ NOTE prior loan as mutable granted here
|
|
//~^ NOTE prior loan as mutable granted here
|
|
|
|
p.purem(); //~ ERROR loan of mutable local variable as immutable conflicts with prior loan
|
|
p.impurem(); //~ ERROR loan of mutable local variable as immutable conflicts with prior loan
|
|
}
|
|
|
|
fn c() {
|
|
// Here the receiver is in aliased memory and hence we cannot
|
|
// consider it immutable:
|
|
let q = @mut {x: 3, y: 4};
|
|
|
|
// ...this is ok for pure fns
|
|
(*q).purem();
|
|
|
|
// ...but not impure fns
|
|
(*q).impurem(); //~ ERROR illegal borrow unless pure: creating immutable alias to aliasable, mutable memory
|
|
//~^ NOTE impure due to access to impure function
|
|
}
|
|
|
|
fn main() {
|
|
}
|
|
|