Add new test

Author: DougGregor

test/Concurrency/sendable_preconcurrency_unused.swift

@@ -0,0 +1,18 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/StrictModule.swiftmodule -module-name StrictModule -warn-concurrency %S/Inputs/StrictModule.swift
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/NonStrictModule.swiftmodule -module-name NonStrictModule %S/Inputs/NonStrictModule.swift
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -I %t
+
+// REQUIRES: concurrency
+
+@preconcurrency import NonStrictModule
+
+struct MyType {
+  var nsc: NonStrictClass
+}
+
+func test(mt: MyType, nsc: NonStrictClass) {
+  Task {
+    print(mt)
+  }
+}