44 lines
974 B
Rust
44 lines
974 B
Rust
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// compile-fail
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#![feature(specialization)]
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// Test that attempting to override a non-default method or one not in the
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// parent impl causes an error
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trait Foo {
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fn foo(&self) -> bool { true }
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}
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// Specialization tree for Foo:
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//
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// Box<T> Vec<T>
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// / \ / \
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// Box<i32> Box<i64> Vec<()> Vec<bool>
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impl<T> Foo for Box<T> {
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fn foo(&self) -> bool { false }
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}
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// Allowed
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impl Foo for Box<i32> {}
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// Can't override a non-`default` fn
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impl Foo for Box<i64> {
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fn foo(&self) -> bool { true }
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//~^ error: `foo` specializes an item from a parent `impl`, but that item is not marked `default`
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}
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// Doesn't mention the method = provided body is used and the method is final
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impl<T> Foo for Vec<T> {}
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// Allowed
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impl Foo for Vec<()> {}
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impl Foo for Vec<bool> {
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fn foo(&self) -> bool { true }
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//~^ error: `foo` specializes an item from a parent `impl`, but that item is not marked `default`
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}
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fn main() {}
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