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