[SR-4138] Static properties are allowed to use without qualifier in initializer of instance property

[swift-ci]

Previous ID	SR-4138
Radar	None
Original Reporter	Max Medvedev (JIRA User)
Type	Bug

Additional Detail from JIRA

| | | |------------------|-----------------| |Votes | 0 | |Component/s | Compiler | |Labels | Bug | |Assignee | None | |Priority | Medium | md5: c9706e2038e23de6e1ecffd1c78b09da

relates to:

• SR-4559 Method called 'self' can be confused with regular 'self'

Issue Description:

Swift 3 forbids to use static members without qualifier in instance context. But it's still allowed to use static properties in initializers of instance properties (though it's forbidden to use static methods there)

An example:

class A {
  static var staticProp = 0
  static func staticFunc()->Int { return 0 }

  var instanceProp = staticProp /*allowed*/ + staticFunc() /*forbidden*/
  var instanceComputedProp: Int { staticProp /*forbidden*/ + staticFunc() /*forbidden*/ }
  func instanceFunc() {
    var _ = staticProp/*forbidden*/ + staticFunc()/*forbidden*/
  } 
}

[belkadan]

@jckarter, we have dups for this, right?

[jckarter]

I don't recall this exact problem, but it's related to the problems with referring to `self` in `lazy` property initializers. The initializer expressions are evaluated as if they're in static rather than instance context, with some not-terribly-principled hacks to try to use instance context in certain situations.