49 lines
1.2 KiB
Rust
49 lines
1.2 KiB
Rust
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// Test that we don't duplicate storage for a variable that is moved to another
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// binding. This used to happen in the presence of unwind and drop edges (see
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// `complex` below.)
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//
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// The exact sizes here can change (we'd like to know when they do). What we
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// don't want to see is the `complex` generator size being upwards of 2048 bytes
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// (which would indicate it is reserving space for two copies of Foo.)
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//
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// See issue #59123 for a full explanation.
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// edition:2018
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#![feature(generators, generator_trait)]
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use std::ops::Generator;
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const FOO_SIZE: usize = 1024;
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struct Foo([u8; FOO_SIZE]);
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impl Drop for Foo {
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fn drop(&mut self) {}
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}
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fn simple() -> impl Generator<Yield = (), Return = ()> {
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static || {
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let first = Foo([0; FOO_SIZE]);
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let _second = first;
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yield;
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// _second dropped here
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}
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}
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fn noop() {}
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fn complex() -> impl Generator<Yield = (), Return = ()> {
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static || {
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let first = Foo([0; FOO_SIZE]);
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noop();
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let _second = first;
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yield;
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// _second dropped here
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}
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}
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fn main() {
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assert_eq!(1028, std::mem::size_of_val(&simple()));
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assert_eq!(1032, std::mem::size_of_val(&complex()));
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}
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