Trait bounds for type inference

[tisonkun]

So far, we have only Unbounded to bound the supported types.

However, this may cause issues like (ref):

BSize::kib(16_u64); // compile failed; multiple applicable items in scope
BSize::<u64>::kib(16_u64); // compiled

I'm considering to change the unsigned.rs file to bounds.rs and add a series of trait bounds:

ByteSize = the current Unsigned
SupportKB = [u16, u32, u64, usize]
SupportKiB = [u16, u32, u64, usize]
SupportMB = [u32, u64, usize]
SupportMiB = [u32, u64, usize]
...

Let me demonstrate a changeset and see if it works well or adds too much type noise.

[tisonkun]

Blocked by

• Tracking Issue for const_ops rust-lang/rust#143802
• Tracking Issue for RFC 3762, "Make trait methods callable in const contexts" rust-lang/rust#143874