Andrew Trick e3f5de90ac [Exclusivity] fix diagnostics for conditional noescape closures. ...

Add support to static diagnostics for tracking noescape closures through block
arguments.

Improve the noescape closure SIL verification logic to match. Cleanup noescape
closure handling in both diagnostics and SIL verification to be more
robust--they must perfectly match each other.

Fixes <rdar://problem/42560459> [Exclusivity] Failure to statically diagnose a
conflict when passing conditional noescape closures.

Initially reported in [SR-8266] Compiler crash when checking exclusivity of
inout alias.

Example:

struct S {
  var x: Int

  mutating func takeNoescapeClosure(_ f: ()->()) { f() }

  mutating func testNoescapePartialApplyPhiUse(z : Bool) {
    func f1() {
      x = 1 // expected-note {{conflicting access is here}}
    }
    func f2() {
      x = 1 // expected-note {{conflicting access is here}}
    }
    takeNoescapeClosure(z ? f1 : f2)
    // expected-error@-1 2 {{overlapping accesses to 'self', but modification requires exclusive access; consider copying to a local variable}}
  }
}

2018-07-30 14:42:30 -07:00

26 KiB

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