Comment by Raphael (JIRA)

Particularly nasty: checking if a collection of enum values contains a certain case:

Comment by Dave Yost (JIRA)

Seems clear that any expression that works as a condition in if, while, etc., is an expression with a Boolean value and therefore should be usable as a Boolean expression.

Comment by Suyeol Jeon (JIRA)

It would be really useful when writing test codes.

let value: MyEnum

// as-is
XCTAssertTrue({
  if case .myCase = value {
    return true
  }
  return false
}())

// to-be
XCTAssert(case .myCase = value)
XCTAssert(value.isCase(.myCase))

This idea should be mediated by a proposal to swift evolution, not a bug sitting on me that I won't get a chance to do.

Swapping statuses because this issue is older than its duplicate.