3 files changed, 14 insertions, 5 deletions
diff --git a/modules/gdscript/gdscript_editor.cpp b/modules/gdscript/gdscript_editor.cpp
index d91e32249e..fa80c31984 100644
--- a/modules/gdscript/gdscript_editor.cpp
+++ b/modules/gdscript/gdscript_editor.cpp
@@ -2054,7 +2054,7 @@ static void _find_identifiers_in_base(const GDScriptCompletionContext &p_context
 
 				if (!p_only_functions) {
 					List<PropertyInfo> members;
-					tmp.get_property_list(&members);
+					p_base.value.get_property_list(&members);
 
 					for (List<PropertyInfo>::Element *E = members.front(); E; E = E->next()) {
 						if (String(E->get().name).find("/") == -1) {
diff --git a/modules/gdscript/gdscript_parser.cpp b/modules/gdscript/gdscript_parser.cpp
index de15f939ce..9590009a54 100644
--- a/modules/gdscript/gdscript_parser.cpp
+++ b/modules/gdscript/gdscript_parser.cpp
@@ -3369,7 +3369,7 @@ void GDScriptParser::_parse_extends(ClassNode *p_class) {
 		return;
 	}
 
-	if (!p_class->constant_expressions.empty() || !p_class->subclasses.empty() || !p_class->functions.empty() || !p_class->variables.empty()) {
+	if (!p_class->constant_expressions.empty() || !p_class->subclasses.empty() || !p_class->functions.empty() || !p_class->variables.empty() || p_class->classname_used) {
 
 		_set_error("'extends' must be used before anything else.");
 		return;
@@ -3506,6 +3506,12 @@ void GDScriptParser::_parse_class(ClassNode *p_class) {
 					_set_error("'class_name' syntax: 'class_name <UniqueName>'");
 					return;
 				}
+				if (p_class->classname_used) {
+					_set_error("'class_name' already used for this class.");
+					return;
+				}
+
+				p_class->classname_used = true;
 
 				p_class->name = tokenizer->get_token_identifier(1);
 
@@ -5248,6 +5254,7 @@ void GDScriptParser::_determine_inheritance(ClassNode *p_class) {
 			if (base_script.is_valid()) {
 
 				String ident = base;
+				Ref<GDScript> find_subclass = base_script;
 
 				for (int i = extend_iter; i < p_class->extends_class.size(); i++) {
 
@@ -5257,7 +5264,7 @@ void GDScriptParser::_determine_inheritance(ClassNode *p_class) {
 
 					if (base_script->get_subclasses().has(subclass)) {
 
-						base_script = base_script->get_subclasses()[subclass];
+						find_subclass = base_script->get_subclasses()[subclass];
 					} else if (base_script->get_constants().has(subclass)) {
 
 						Ref<GDScript> new_base_class = base_script->get_constants()[subclass];
@@ -5265,7 +5272,7 @@ void GDScriptParser::_determine_inheritance(ClassNode *p_class) {
 							_set_error("Constant is not a class: " + ident, p_class->line);
 							return;
 						}
-						base_script = new_base_class;
+						find_subclass = new_base_class;
 					} else {
 
 						_set_error("Could not find subclass: " + ident, p_class->line);
@@ -5273,7 +5280,7 @@ void GDScriptParser::_determine_inheritance(ClassNode *p_class) {
 					}
 				}
 
-				script = base_script;
+				script = find_subclass;
 
 			} else if (!base_class) {
 
diff --git a/modules/gdscript/gdscript_parser.h b/modules/gdscript/gdscript_parser.h
index 809bff8f20..5e4de11357 100644
--- a/modules/gdscript/gdscript_parser.h
+++ b/modules/gdscript/gdscript_parser.h
@@ -149,6 +149,7 @@ public:
 		bool tool;
 		StringName name;
 		bool extends_used;
+		bool classname_used;
 		StringName extends_file;
 		Vector<StringName> extends_class;
 		DataType base_type;
@@ -198,6 +199,7 @@ public:
 			tool = false;
 			type = TYPE_CLASS;
 			extends_used = false;
+			classname_used = false;
 			end_line = -1;
 			owner = NULL;
 		}