mirror of https://github.com/rust-lang/rust
58 lines
1.2 KiB
Rust
58 lines
1.2 KiB
Rust
// Test that we cannot mutate an outer variable that is not declared
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// as `mut` through a closure. Also test that we CAN mutate a moved copy,
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// unless this is a `Fn` closure. Issue #16749.
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#![feature(unboxed_closures, tuple_trait)]
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use std::mem;
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fn to_fn<A:std::marker::Tuple,F:Fn<A>>(f: F) -> F { f }
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fn to_fn_mut<A:std::marker::Tuple,F:FnMut<A>>(f: F) -> F { f }
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fn a() {
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let n = 0;
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let mut f = to_fn_mut(|| {
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n += 1; //~ ERROR cannot assign to `n`, as it is not declared as mutable
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});
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}
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fn b() {
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let mut n = 0;
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let mut f = to_fn_mut(|| {
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n += 1; // OK
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});
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}
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fn c() {
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let n = 0;
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let mut f = to_fn_mut(move || {
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// If we just did a straight-forward desugaring, this would
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// compile, but we do something a bit more subtle, and hence
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// we get an error.
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n += 1; //~ ERROR cannot assign
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});
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}
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fn d() {
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let mut n = 0;
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let mut f = to_fn_mut(move || {
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n += 1; // OK
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});
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}
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fn e() {
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let n = 0;
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let mut f = to_fn(move || {
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n += 1; //~ ERROR cannot assign
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});
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}
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fn f() {
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let mut n = 0;
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let mut f = to_fn(move || {
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n += 1; //~ ERROR cannot assign
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});
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}
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fn main() { }
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