diff --git a/src/ifcparse/IfcSchema.cpp b/src/ifcparse/IfcSchema.cpp
index 2d26efa0da..a21023a865 100644
--- a/src/ifcparse/IfcSchema.cpp
+++ b/src/ifcparse/IfcSchema.cpp
@@ -13,8 +13,8 @@ bool IfcParse::declaration::is(const std::string& name) const {
 
 	if (name_upper_ == *name_ptr) return true;
 
-	if (this->as_entity()) {
-		return this->as_entity()->is(name);
+	if (this->as_entity() && this->as_entity()->supertype()) {
+		return this->as_entity()->supertype()->is(name);
 	} else if (this->as_type_declaration()) {
 		const IfcParse::named_type* nt = this->as_type_declaration()->declared_type()->as_named_type();
 		if (nt) return nt->is(name);
@@ -26,8 +26,8 @@ bool IfcParse::declaration::is(const std::string& name) const {
 bool IfcParse::declaration::is(const IfcParse::declaration& decl) const {
 	if (this == &decl) return true;
 
-	if (this->as_entity()) {
-		return this->as_entity()->is(decl);
+	if (this->as_entity() && this->as_entity()->supertype()) {
+		return this->as_entity()->supertype()->is(decl);
 	} else if (this->as_type_declaration()) {
 		const IfcParse::named_type* nt = this->as_type_declaration()->declared_type()->as_named_type();
 		if (nt) return nt->is(decl);
diff --git a/src/ifcparse/IfcSchema.h b/src/ifcparse/IfcSchema.h
index 4ec3e93b7d..5661530844 100644
--- a/src/ifcparse/IfcSchema.h
+++ b/src/ifcparse/IfcSchema.h
@@ -293,18 +293,6 @@ namespace IfcParse {
 
 		virtual ~entity();
 
-		bool is(const std::string& name) const {
-			if (name == name_) return true;
-			else if (supertype_) return supertype_->is(name);
-			else return false;
-		}
-
-		bool is(const IfcParse::declaration& decl) const {
-			if (this == &decl) return true;
-			else if (supertype_) return supertype_->is(decl);
-			else return false;
-		}
-
 		bool is_abstract() const { return is_abstract_; }
 
 		void set_subtypes(const std::vector<const entity*>& subtypes) {