mirror of https://github.com/rust-lang/rust
60 lines
1.3 KiB
Rust
60 lines
1.3 KiB
Rust
// Tests that two closures cannot simultaneously have mutable
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// access to the variable, whether that mutable access be used
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// for direct assignment or for taking mutable ref. Issue #6801.
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fn to_fn_mut<F: FnMut()>(f: F) -> F { f }
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fn a() {
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let mut x = 3;
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let c1 = to_fn_mut(|| x = 4);
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let c2 = to_fn_mut(|| x = 5); //~ ERROR cannot borrow `x` as mutable more than once
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c1;
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}
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fn set(x: &mut isize) {
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*x = 4;
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}
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fn b() {
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let mut x = 3;
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let c1 = to_fn_mut(|| set(&mut x));
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let c2 = to_fn_mut(|| set(&mut x)); //~ ERROR cannot borrow `x` as mutable more than once
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c1;
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}
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fn c() {
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let mut x = 3;
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let c1 = to_fn_mut(|| x = 5);
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let c2 = to_fn_mut(|| set(&mut x)); //~ ERROR cannot borrow `x` as mutable more than once
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c1;
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}
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fn d() {
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let mut x = 3;
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let c1 = to_fn_mut(|| x = 5);
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let c2 = to_fn_mut(|| { let _y = to_fn_mut(|| set(&mut x)); }); // (nested closure)
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//~^ ERROR cannot borrow `x` as mutable more than once
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c1;
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}
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fn g() {
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struct Foo {
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f: Box<isize>
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}
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let mut x: Box<_> = Box::new(Foo { f: Box::new(3) });
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let c1 = to_fn_mut(|| set(&mut *x.f));
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let c2 = to_fn_mut(|| set(&mut *x.f));
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//~^ ERROR cannot borrow `x` as mutable more than once
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c1;
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}
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fn main() {
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}
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