40 lines
815 B
Rust
40 lines
815 B
Rust
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// check-pass
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use std::marker::PhantomData;
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use std::mem;
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trait Container<'a> {
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type Root: 'a;
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}
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type RootOf<'a, T> = <T as Container<'a>>::Root;
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struct Test<'a, T> where T: Container<'a> {
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pub root: T::Root,
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marker: PhantomData<&'a mut &'a mut ()>,
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}
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impl<'a, 'b> Container<'b> for &'a str {
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type Root = &'b str;
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}
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impl<'a, T> Test<'a, T> where T: for<'b> Container<'b> {
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fn new(root: RootOf<'a, T>) -> Test<'a, T> {
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Test {
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root: root,
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marker: PhantomData
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}
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}
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fn with_mut<F, R>(&mut self, f: F) -> R where
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F: for<'b> FnOnce(&'b mut RootOf<'b, T>) -> R {
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f(unsafe { mem::transmute(&mut self.root) })
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}
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}
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fn main() {
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let val = "root";
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let mut test: Test<&str> = Test::new(val);
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test.with_mut(|_| { });
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}
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