[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

@@ -509,6 +509,26 @@ namespace {
         return importFunctionPointerLikeType(*type, pointeeType);
       }
 
+      // If non-copyable generics are disabled, we cannot specify
+      // UnsafePointer<T> with a non-copyable type T.
+      // We cannot use `ty->isNoncopyable()` here because that would create a
+      // cyclic dependency between ModuleQualifiedLookupRequest and
+      // LookupConformanceInModuleRequest, so we check for the presence of
+      // move-only attribute that is implicitly added to non-copyable C++ types
+      // by ClangImporter.
+      if (pointeeType && pointeeType->getAnyNominal() &&
+          pointeeType->getAnyNominal()
+              ->getAttrs()
+              .hasAttribute<MoveOnlyAttr>() &&
+          !Impl.SwiftContext.LangOpts.hasFeature(
+              Feature::NoncopyableGenerics)) {
+        auto opaquePointerDecl = Impl.SwiftContext.getOpaquePointerDecl();
+        if (!opaquePointerDecl)
+          return Type();
+        return {opaquePointerDecl->getDeclaredInterfaceType(),
+                ImportHint::OtherPointer};
+      }
+
       PointerTypeKind pointerKind;
       if (quals.hasConst()) {
         pointerKind = PTK_UnsafePointer;

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>