Add a lifetime dependence test case for nonescaping closures.

Author: atrick

test/SILOptimizer/lifetime_dependence_closure.swift

@@ -0,0 +1,53 @@
+// RUN: %target-swift-frontend %s -emit-sil \
+// RUN:   -o /dev/null \
+// RUN:   -verify \
+// RUN:   -sil-verify-all \
+// RUN:   -module-name test \
+// RUN:   -disable-experimental-parser-round-trip \
+// RUN:   -enable-experimental-feature NonescapableTypes
+
+// REQUIRES: asserts
+// REQUIRES: swift_in_compiler
+
+struct NCInt: ~Copyable {
+  var value: Int
+
+  init(_ value: Int) { self.value = value }
+}
+
+@_nonescapable
+struct NEInt /*: ~Escapable*/ {
+  let value: Int
+
+  init(borrowed: borrowing NCInt) -> _borrow(borrowed) Self {
+    self.value = borrowed.value
+    return self
+  }
+}
+
+extension NCInt {
+  var neInt: NEInt {
+    borrowing get {
+      NEInt(borrowed: self)
+    }
+  }
+}
+
+func ncint_get_neint_mutable_local() {
+  var ncInt = NCInt(731)
+  do {
+    // Begin read access ncInt
+    var neInt = ncInt.neInt
+
+    // Capture neInt in a nonescapable closure.
+    assert(ncInt.value == neInt.value)
+    // End read access ncInt
+
+    // Begin read access ncInt
+    // Fully reassign neInt
+    neInt = ncInt.neInt
+    // Destroy neInt
+    // End read access ncInt
+  }
+  ncInt.value = 1
+}