diff --git a/ext/java/nokogiri/XmlSchema.java b/ext/java/nokogiri/XmlSchema.java
index ea3e55eff0..d965965976 100644
--- a/ext/java/nokogiri/XmlSchema.java
+++ b/ext/java/nokogiri/XmlSchema.java
@@ -143,18 +143,18 @@ public class XmlSchema extends RubyObject
   public static IRubyObject
   from_document(ThreadContext context, IRubyObject klazz, IRubyObject[] args)
   {
-    IRubyObject document = args[0];
+    IRubyObject rbDocument = args[0];
     IRubyObject parseOptions = null;
     if (args.length > 1) {
       parseOptions = args[1];
     }
 
-    if (!(document instanceof XmlDocument)) {
+    if (!(rbDocument instanceof XmlDocument)) {
       // TODO: deprecate allowing Node
       context.runtime.getWarnings().warn("Passing a Node as the first parameter to Schema.from_document is deprecated. Please pass a Document instead. This will become an error in a future release of Nokogiri.");
     }
 
-    XmlDocument doc = ((XmlDocument)((XmlNode) document).document(context));
+    XmlDocument doc = ((XmlDocument)((XmlNode) rbDocument).document(context));
 
     RubyArray<?> errors = (RubyArray) doc.getInstanceVariable("@errors");
     if (!errors.isEmpty()) {
diff --git a/ext/nokogiri/xml_schema.c b/ext/nokogiri/xml_schema.c
index 5aeecb1e6f..c08eb11d79 100644
--- a/ext/nokogiri/xml_schema.c
+++ b/ext/nokogiri/xml_schema.c
@@ -203,7 +203,7 @@ read_memory(int argc, VALUE *argv, VALUE klass)
  * [Returns] Nokogiri::XML::Schema
  */
 static VALUE
-from_document(int argc, VALUE *argv, VALUE klass)
+rb_xml_schema_s_from_document(int argc, VALUE *argv, VALUE klass)
 {
   VALUE rb_document;
   VALUE rb_parse_options;
@@ -214,14 +214,14 @@ from_document(int argc, VALUE *argv, VALUE klass)
 
   rb_scan_args(argc, argv, "11", &rb_document, &rb_parse_options);
 
-  if (rb_obj_is_kind_of(rb_document, cNokogiriXmlDocument)) {
-    c_document = noko_xml_document_unwrap(rb_document);
-  } else {
+  if (!rb_obj_is_kind_of(rb_document, cNokogiriXmlDocument)) {
     xmlNodePtr deprecated_node_type_arg;
     // TODO: deprecate allowing Node
     NOKO_WARN_DEPRECATION("Passing a Node as the first parameter to Schema.from_document is deprecated. Please pass a Document instead. This will become an error in a future release of Nokogiri.");
     Noko_Node_Get_Struct(rb_document, xmlNode, deprecated_node_type_arg);
     c_document = deprecated_node_type_arg->doc;
+  } else {
+    c_document = noko_xml_document_unwrap(rb_document);
   }
 
   if (noko_xml_document_has_wrapped_blank_nodes_p(c_document)) {
@@ -249,7 +249,7 @@ noko_init_xml_schema(void)
   rb_undef_alloc_func(cNokogiriXmlSchema);
 
   rb_define_singleton_method(cNokogiriXmlSchema, "read_memory", read_memory, -1);
-  rb_define_singleton_method(cNokogiriXmlSchema, "from_document", from_document, -1);
+  rb_define_singleton_method(cNokogiriXmlSchema, "from_document", rb_xml_schema_s_from_document, -1);
 
   rb_define_private_method(cNokogiriXmlSchema, "validate_document", validate_document, 1);
   rb_define_private_method(cNokogiriXmlSchema, "validate_file",     validate_file, 1);