[cxx-interop] Import NonCopyable* as OpaquePointer if noncopyable generics are disabled

C++ pointer type `T*` is generally imported as `Unsafe(Mutable)Pointer<T>`. However, if `T` is non-copyable in Swift (e.g. it has a deleted C++ copy constructor), using `UnsafePointer<T>` type requires noncopyable generics to be enabled.

This was causing assertion failures when building SwiftCompilerSources in #72912.

Author: egorzhdan

lib/ClangImporter/ImportType.cpp

@@ -498,6 +498,18 @@ namespace {
       if (pointeeType && pointeeType->isForeignReferenceType())
          return {pointeeType, ImportHint::OtherPointer};
 
+      // If non-copyable generics are disabled, we cannot specify
+      // UnsafePointer<T> with a non-copyable type T.
+      if (pointeeType && pointeeType->isNoncopyable() &&
+          !Impl.SwiftContext.LangOpts.hasFeature(
+              Feature::NoncopyableGenerics)) {
+        auto opaquePointerDecl = Impl.SwiftContext.getOpaquePointerDecl();
+        if (!opaquePointerDecl)
+          return Type();
+        return {opaquePointerDecl->getDeclaredInterfaceType(),
+                ImportHint::OtherPointer};
+      }
+
       // If the pointed-to type is unrepresentable in Swift, or its C
       // alignment is greater than the maximum Swift alignment, import as
       // OpaquePointer.

test/Interop/Cxx/class/move-only/Inputs/move-only-cxx-value-type.h

@@ -53,4 +53,7 @@ struct NonCopyableHolderDerivedDerived: NonCopyableHolderDerived {
     }
 };
 
+inline NonCopyable *getNonCopyablePtr() { return nullptr; }
+inline NonCopyableDerived *getNonCopyableDerivedPtr() { return nullptr; }
+
 #endif // TEST_INTEROP_CXX_CLASS_MOVE_ONLY_VT_H

test/Interop/Cxx/class/move-only/move-only-cxx-value-type-module-interface.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=MoveOnlyCxxValueType -I %S/Inputs -cxx-interoperability-mode=upcoming-swift -source-filename=x | %FileCheck %s --check-prefix=CHECK-NO-NCG
+// RUN: %target-swift-ide-test -print-module -module-to-print=MoveOnlyCxxValueType -I %S/Inputs -cxx-interoperability-mode=upcoming-swift -source-filename=x -enable-experimental-feature NoncopyableGenerics | %FileCheck %s --check-prefix=CHECK-NCG
+
+// CHECK-NO-NCG: func getNonCopyablePtr() -> OpaquePointer
+// CHECK-NO-NCG: func getNonCopyableDerivedPtr() -> OpaquePointer
+
+// CHECK-NCG: func getNonCopyablePtr() -> UnsafeMutablePointer<NonCopyable>
+// CHECK-NCG: func getNonCopyableDerivedPtr() -> UnsafeMutablePointer<NonCopyableDerived>