Add unit test for lifetime dependence related to function types

Author: meg-gupta

test/Sema/lifetime_dependence_functype.swift

@@ -0,0 +1,47 @@
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature NonescapableTypes
+// REQUIRES: asserts
+
+struct NC: ~Copyable {
+  var ne: NE {
+    NE()
+  }
+}
+
+struct NE: ~Escapable {
+  @_unsafeNonescapableResult
+  init() {}
+}
+
+func transfer(_ ne: NE) -> NE {
+  ne
+}
+
+func applyAnnotatedTransfer(ne: NE, transfer: (NE) -> dependsOn(0) NE) -> NE { // expected-error{{Lifetime dependencies on function types are not yet supported}}
+  transfer(ne)
+}
+
+func applyTransfer(ne: NE, transfer: (NE) ->  NE) -> NE {
+  transfer(ne)
+}
+
+func testTransfer(nc: consuming NC) {
+  let transferred = applyTransfer(ne: nc.ne, transfer: transfer) // expected-error{{Conversion between function types with different lifetime dependencies are not allowed}}
+
+  _ = consume nc
+  _ = transfer(transferred)
+}
+
+func borrow(_ nc: borrowing NC) -> NE {
+  nc.ne
+}
+
+func applyBorrow(nc: borrowing NC, borrow: (borrowing NC) -> NE) -> NE {
+  borrow(nc)
+}
+
+func testBorrow(nc: consuming NC) {
+  let borrowed = applyBorrow(nc: nc, borrow: borrow) // expected-error{{Conversion between function types with different lifetime dependencies are not allowed}}
+  _ = consume nc
+  _ = transfer(borrowed)
+}
+