Please separate `clippy::precedence` into multiple lints

[joshtriplett]

I really appreciate the part of clippy::precedence that flags "mixed usage of arithmetic and bit shifting/combining operators without parentheses" (e.g. 1 << 2 + 3).

I would rather not have the part of clippy::precedence that flags "mixed usage of bitmasking and bit shifting operators without parentheses", because when you work with bitmasking regularly, it's reasonably well-known that x | 1 << 10 or y & 1 << 10 has the precedence you would expect.

Could clippy separate these into two separate lints, e.g. clippy::precedence_arithmetic_vs_bits and clippy::precedence_bits?

(I would also make the case that the latter should be allow-by-default, but for this issue I'm just requesting that the two be split.)

[samueltardieu]

Agreed, as doing a lot of embedded programming and bit manipulation, this bugs me as well. I think the lint on shifting/combining operators should be in restriction.