mirror of https://github.com/rust-lang/rust
76 lines
3.2 KiB
Rust
76 lines
3.2 KiB
Rust
//@ run-pass
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struct X { val: i32 }
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impl std::ops::Deref for X {
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type Target = i32;
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fn deref(&self) -> &i32 { &self.val }
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}
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trait M { fn m(self); }
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impl M for i32 { fn m(self) { println!("i32::m()"); } }
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impl M for X { fn m(self) { println!("X::m()"); } }
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impl<'a> M for &'a X { fn m(self) { println!("&X::m()"); } }
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impl<'a, 'b> M for &'a &'b X { fn m(self) { println!("&&X::m()"); } }
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impl<'a, 'b, 'c> M for &'a &'b &'c X { fn m(self) { println!("&&&X::m()"); } }
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trait RefM { fn refm(&self); }
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impl RefM for i32 { fn refm(&self) { println!("i32::refm()"); } }
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impl RefM for X { fn refm(&self) { println!("X::refm()"); } }
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impl<'a> RefM for &'a X { fn refm(&self) { println!("&X::refm()"); } }
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impl<'a, 'b> RefM for &'a &'b X { fn refm(&self) { println!("&&X::refm()"); } }
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impl<'a, 'b, 'c> RefM for &'a &'b &'c X { fn refm(&self) { println!("&&&X::refm()"); } }
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struct Y { val: i32 }
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impl std::ops::Deref for Y {
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type Target = i32;
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fn deref(&self) -> &i32 { &self.val }
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}
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struct Z { val: Y }
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impl std::ops::Deref for Z {
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type Target = Y;
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fn deref(&self) -> &Y { &self.val }
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}
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struct A;
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impl std::marker::Copy for A {}
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impl Clone for A { fn clone(&self) -> Self { *self } }
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impl M for A { fn m(self) { println!("A::m()"); } }
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impl<'a, 'b, 'c> M for &'a &'b &'c A { fn m(self) { println!("&&&A::m()"); } }
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impl RefM for A { fn refm(&self) { println!("A::refm()"); } }
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impl<'a, 'b, 'c> RefM for &'a &'b &'c A { fn refm(&self) { println!("&&&A::refm()"); } }
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fn main() {
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// I'll use @ to denote left side of the dot operator
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(*X{val:42}).m(); // i32::refm() , self == @
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X{val:42}.m(); // X::m() , self == @
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(&X{val:42}).m(); // &X::m() , self == @
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(&&X{val:42}).m(); // &&X::m() , self == @
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(&&&X{val:42}).m(); // &&&X:m() , self == @
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(&&&&X{val:42}).m(); // &&&X::m() , self == *@
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(&&&&&X{val:42}).m(); // &&&X::m() , self == **@
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(*X{val:42}).refm(); // i32::refm() , self == @
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X{val:42}.refm(); // X::refm() , self == @
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(&X{val:42}).refm(); // X::refm() , self == *@
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(&&X{val:42}).refm(); // &X::refm() , self == *@
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(&&&X{val:42}).refm(); // &&X::refm() , self == *@
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(&&&&X{val:42}).refm(); // &&&X::refm(), self == *@
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(&&&&&X{val:42}).refm(); // &&&X::refm(), self == **@
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Y{val:42}.refm(); // i32::refm() , self == *@
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Z{val:Y{val:42}}.refm(); // i32::refm() , self == **@
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A.m(); // A::m() , self == @
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// without the Copy trait, (&A).m() would be a compilation error:
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// cannot move out of borrowed content
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(&A).m(); // A::m() , self == *@
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(&&A).m(); // &&&A::m() , self == &@
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(&&&A).m(); // &&&A::m() , self == @
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A.refm(); // A::refm() , self == @
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(&A).refm(); // A::refm() , self == *@
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(&&A).refm(); // A::refm() , self == **@
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(&&&A).refm(); // &&&A::refm(), self == @
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}
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