26 lines
910 B
Rust
26 lines
910 B
Rust
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// Test that we consider these two types completely equal:
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//
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// * `for<'a, 'b> fn(&'a u32, &'b u32)`
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// * `for<'c> fn(&'c u32, &'c u32)`
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//
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// For a long time we considered these to be distinct types. But in fact they
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// are equivalent, if you work through the implications of subtyping -- this is
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// because:
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//
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// * `'c` can be the intersection of `'a` and `'b` (and there is always an intersection)
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// * `'a` and `'b` can both be equal to `'c`
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trait Trait {}
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impl Trait for for<'a, 'b> fn(&'a u32, &'b u32) {}
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impl Trait for for<'c> fn(&'c u32, &'c u32) {
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//~^ ERROR conflicting implementations
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//
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// Note in particular that we do NOT get a future-compatibility warning
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// here. This is because the new leak-check proposed in [MCP 295] does not
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// "error" when these two types are equated.
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//
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// [MCP 295]: https://github.com/rust-lang/compiler-team/issues/295
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}
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fn main() {}
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