Blanket implementing a trait for any type that implments Fn | Rust Programming Language Community | Page 1

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if both T0: SomeTrait and (): Tuple, then which of the impls should the compiler use? ```rs
impl<F: Fn<Args>, Args: Tuple> Function for F {}
impl<F: Fn() -> T0, T0> Function for F where T0: SomeTrait {}

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in general the feature is called specialization and in its full form it's unfinished

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there are simple cases where it works (min_specialization), but I don't think this is exactly one of them

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specifically, the current feature doesn't work when 2 impls are both bounded by different unrelated traits

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yeah, say you have a hypothetical type Foo that implements Fn() and Fn(i32) and both (): Tuple and (i32,): Tuple, then Foo will implement Function in 2 different ways

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which is not allowed

#Blanket implementing a trait for any type that implments Fn