Merge pull request #13343 from rudkx/iuo-test

Add the test case I am using to bring up the new IUO implementation.

Author: rudkx

test/Constraints/iuo.swift

@@ -0,0 +1,116 @@
+// RUN: %target-typecheck-verify-swift
+
+func basic() {
+  var i: Int! = 0
+  let _: Int = i
+  i = 7
+}
+
+func takesIUOs(i: Int!, j: inout Int!) -> Int {
+  j = 7
+  return i
+}
+
+struct S {
+  let i: Int!
+  var j: Int!
+  let k: Int
+  var m: Int
+
+  func fn() -> Int! { return i }
+}
+
+func takesStruct(s: S) {
+  let _: Int = s.i
+  let _: Int = s.j
+  var t: S! = s
+  t.j = 7
+}
+
+var a: (Int, Int)! = (0, 0)
+a.0 = 42
+
+var s: S! = S(i: nil, j: 1, k: 2, m: 3)
+_ = s.i
+let _: Int = s.j
+_ = s.k
+s.m = 7
+s.j = 3
+
+struct T {
+  let i: Float!
+  var j: Float!
+
+  func fn() -> Float! { return i }
+}
+
+func overloaded() -> S { return S(i: 0, j: 1, k: 2, m: 3) }
+func overloaded() -> T { return T(i: 0.5, j: 1.5) }
+
+let _: Int = overloaded().i
+
+func cflow(i: Int!, j: inout Bool!, s: S) {
+  let k: Int? = i
+  let m: Int = i
+  let b: Bool! = i == 0
+
+  if i == 7 {
+    if s.i == 7 {
+    }
+  }
+  let _ = i ? 7 : 0 // expected-error {{optional type 'Int!' cannot be used as a boolean; test for '!= nil' instead}}
+  let _ = b ? i : k
+  let _ = b ? i : m
+  let _ = b ? j : b
+  let _ = i ? i : k // expected-error {{result values in '? :' expression have mismatching types 'Int!' and 'Int?'}}
+  let _ = i ? i : m // expected-error {{result values in '? :' expression have mismatching types 'Int!' and 'Int'}}
+  let _ = s.i ? s.j : s.k // expected-error {{result values in '? :' expression have mismatching types 'Int!' and 'Int'}}
+  let _ = b ? s.j : s.k
+
+  if j {}
+  let _ = j ? 7 : 0
+}
+
+func forcedResultInt() -> Int! {
+  return 0
+}
+
+let _: Int = forcedResultInt()
+
+func forcedResult() -> Int! {
+  return 0
+}
+
+func forcedResult() -> Float! {
+  return 0
+}
+
+func overloadedForcedResult() -> Int {
+  return forcedResult()
+}
+
+func forceMemberResult(s: S) -> Int {
+  return s.fn()
+}
+
+func overloadedForceMemberResult() -> Int {
+  return overloaded().fn()
+}
+
+func overloadedForcedStructResult() -> S! { return S(i: 0, j: 1, k: 2, m: 3) }
+func overloadedForcedStructResult() -> T! { return T(i: 0.5, j: 1.5) }
+
+let _: S = overloadedForcedStructResult()
+let _: Int = overloadedForcedStructResult().i
+
+let x: Int? = 1
+let y0: Int = x as Int! // expected-warning {{using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead}}
+let y1: Int = (x as Int!)! // expected-warning {{using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead}}
+let z0: Int = x as! Int! // expected-warning {{forced cast from 'Int?' to 'Int!' always succeeds; did you mean to use 'as'?}}
+// expected-warning@-1 {{using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead}}
+let z1: Int = (x as! Int!)! // expected-warning {{forced cast from 'Int?' to 'Int!' always succeeds; did you mean to use 'as'?}}
+// expected-warning@-1 {{using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead}}
+let w0: Int = (x as? Int!)! // expected-warning {{conditional cast from 'Int?' to 'Int!' always succeeds}}
+// expected-warning@-1 {{using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead}}
+let w1: Int = (x as? Int!)!! // expected-warning {{conditional cast from 'Int?' to 'Int!' always succeeds}}
+// expected-warning@-1 {{using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead}}