Boolean & and | should be SIP-18ed.

[scabug]

(No description for SI-7156.)

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-7156?orig=1
Reporter: @paulp

[SethTisue]

should they? normally we just follow Java on stuff like this. seems like linter territory to me. as in, third-party linter territory (e.g. Scalafix), not scalac-builtin linting territory