50 lines
880 B
Rust
50 lines
880 B
Rust
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#![feature(unsized_locals)]
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pub trait Foo {
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fn foo(self) -> String;
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}
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struct A;
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impl Foo for A {
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fn foo(self) -> String {
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format!("hello")
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}
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}
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struct B(i32);
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impl Foo for B {
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fn foo(self) -> String {
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format!("{}", self.0)
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}
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}
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struct C(String);
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impl Foo for C {
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fn foo(self) -> String {
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self.0
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}
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}
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struct D(Box<String>);
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impl Foo for D {
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fn foo(self) -> String {
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*self.0
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}
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}
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fn main() {
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let x = *(Box::new(A) as Box<dyn Foo>);
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assert_eq!(x.foo(), format!("hello"));
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let x = *(Box::new(B(42)) as Box<dyn Foo>);
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assert_eq!(x.foo(), format!("42"));
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let x = *(Box::new(C(format!("jumping fox"))) as Box<dyn Foo>);
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assert_eq!(x.foo(), format!("jumping fox"));
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let x = *(Box::new(D(Box::new(format!("lazy dog")))) as Box<dyn Foo>);
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assert_eq!(x.foo(), format!("lazy dog"));
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}
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