ClangImporter: Use VariadicSequenceType instead of ArrayType for vararg parameters

Author: slavapestov

lib/ClangImporter/ImportType.cpp

@@ -2410,9 +2410,8 @@ ParameterList *ClangImporter::Implementation::importFunctionParameterList(
 
   // Append an additional argument to represent varargs.
   if (isVariadic) {
-    auto paramTy =
-        BoundGenericType::get(SwiftContext.getArrayDecl(), Type(),
-                              {SwiftContext.getAnyExistentialType()});
+    auto paramTy = VariadicSequenceType::get(
+        SwiftContext.getAnyExistentialType());
     auto name = SwiftContext.getIdentifier("varargs");
     auto param = new (SwiftContext) ParamDecl(SourceLoc(), SourceLoc(),
                                               Identifier(), SourceLoc(),