21 lines
644 B
Rust
21 lines
644 B
Rust
// Ensure that you cannot use generic types to return a region outside
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// of its bound. Here, in the `return_it()` fn, we call with() but
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// with R bound to &int from the return_it. Meanwhile, with()
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// provides a value that is only good within its own stack frame. This
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// used to successfully compile because we failed to account for the
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// fact that fn(x: &int) rebound the region &.
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fn with<R>(f: fn(x: &int) -> R) -> R {
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f(&3)
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}
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fn return_it() -> &int {
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with(|o| o) //~ ERROR mismatched types
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//~^ ERROR reference is not valid outside of its lifetime
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}
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fn main() {
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let x = return_it();
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debug!("foo=%d", *x);
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}
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