45 lines
1.3 KiB
Rust
45 lines
1.3 KiB
Rust
// The regression test for #15031 to make sure destructuring trait
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// reference work properly.
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#![feature(box_patterns)]
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trait T { fn foo(&self) {} }
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impl T for isize {}
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fn main() {
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// For an expression of the form:
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//
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// let &...&x = &..&SomeTrait;
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//
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// Say we have n `&` at the left hand and m `&` right hand, then:
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// if n < m, we are golden;
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// if n == m, it's a derefing non-derefable type error;
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// if n > m, it's a type mismatch error.
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// n < m
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let &x = &(&1isize as &dyn T);
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let &x = &&(&1isize as &dyn T);
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let &&x = &&(&1isize as &dyn T);
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// n == m
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let &x = &1isize as &dyn T; //~ ERROR type `&dyn T` cannot be dereferenced
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let &&x = &(&1isize as &dyn T); //~ ERROR type `&dyn T` cannot be dereferenced
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let box x = Box::new(1isize) as Box<dyn T>;
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//~^ ERROR type `Box<dyn T>` cannot be dereferenced
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// n > m
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let &&x = &1isize as &dyn T;
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//~^ ERROR mismatched types
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//~| expected trait object `dyn T`
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//~| found reference `&_`
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let &&&x = &(&1isize as &dyn T);
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//~^ ERROR mismatched types
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//~| expected trait object `dyn T`
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//~| found reference `&_`
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let box box x = Box::new(1isize) as Box<dyn T>;
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//~^ ERROR mismatched types
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//~| expected trait object `dyn T`
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//~| found struct `Box<_>`
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}
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