Cannot define the same inherent method in disjoint blocks

[aturon]

Currently, the following fails to compile:

struct Foo<T>;

impl<'a, T> Foo<&'a T> {
    fn foo(&self) {}
}
impl<'a, T> Foo<&'a mut T> {
    fn foo(&self) {}
}

The error:

<anon>:7:5: 7:21 error: duplicate definition of value `foo`
<anon>:7     fn foo(&self) {}
             ^~~~~~~~~~~~~~~~
<anon>:4:5: 4:21 note: first definition of value `foo` here
<anon>:4     fn foo(&self) {}
             ^~~~~~~~~~~~~~~~

If you construct an analogous situation using two separate impls of a trait providing foo, it works just fine, because there is no overlap. Inherent impl blocks could be similarly flexible.

[aturon]

cc @nikomatsakis

[reem]

cc me

[bluss]

The example now compiles with struct Foo<T>(T);.