Hi, I'm trying to write a Sub impl for references to Points. Everything works fine when types are given explicitly but then fails due to a recursive requirement when I try to write a generic function. The full code is here: Rust Playground
I'm new to Rust so any hints or insight would be helpful.
Thanks.
I believe this might be a bug in type inference. If you explicitly specify the parameters in the call, i.e. test::<i32, 2>(&a), then the code compiles. An important thing to note here is that the error message talks about &Point<BTreeSet<_>, {_: usize}> or &Point<HashSet<_, _>, {_: usize}> (depending on the choice of nightly vs stable). I don’t really see any reason of why type inference should start considering HashSet or BTreeSet for any of this, in fact, the type of &a should be very clearly known so it’s questionably that the explicit test::<i32, 2> should be needed to avoid any ambiguities or something like that.
Looks like #39959.
Edit: Maybe not exactly this one, I’m not sure if the examples given in this issues are actually expected to compile…
That does look like what I'm encountering. Will work around the issue by cloning my values.
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