diff --git a/src/mapblock.cpp b/src/mapblock.cpp
index bf7f9dcd3..ed4f09692 100644
--- a/src/mapblock.cpp
+++ b/src/mapblock.cpp
@@ -492,19 +492,17 @@ static void correctBlockNodeIds(const NameIdMapping *nimap, MapNode *nodes,
 	// the information to convert those to names.
 	// nodedef contains information to convert our names to globally
 	// correct ids.
-	std::set<content_t> unnamed_contents;
-	std::set<std::string> unallocatable_contents;
+	std::unordered_set<content_t> unnamed_contents;
+	std::unordered_set<std::string> unallocatable_contents;
 	for (u32 i = 0; i < MapBlock::nodecount; i++) {
 		content_t local_id = nodes[i].getContent();
 		std::string name;
-		bool found = nimap->getName(local_id, name);
-		if(!found){
+		if (!nimap->getName(local_id, name)) {
 			unnamed_contents.insert(local_id);
 			continue;
 		}
 		content_t global_id;
-		found = nodedef->getId(name, global_id);
-		if(!found){
+		if (!nodedef->getId(name, global_id)) {
 			global_id = gamedef->allocateUnknownNodeId(name);
 			if(global_id == CONTENT_IGNORE){
 				unallocatable_contents.insert(name);
@@ -513,19 +511,16 @@ static void correctBlockNodeIds(const NameIdMapping *nimap, MapNode *nodes,
 		}
 		nodes[i].setContent(global_id);
 	}
-	for(std::set<content_t>::const_iterator
-			i = unnamed_contents.begin();
-			i != unnamed_contents.end(); ++i){
-		errorstream<<"correctBlockNodeIds(): IGNORING ERROR: "
-				<<"Block contains id "<<(*i)
-				<<" with no name mapping"<<std::endl;
+
+	for (const content_t c: unnamed_contents) {
+		errorstream << "correctBlockNodeIds(): IGNORING ERROR: "
+				<< "Block contains id " << c
+				<< " with no name mapping" << std::endl;
 	}
-	for(std::set<std::string>::const_iterator
-			i = unallocatable_contents.begin();
-			i != unallocatable_contents.end(); ++i){
-		errorstream<<"correctBlockNodeIds(): IGNORING ERROR: "
-				<<"Could not allocate global id for node name \""
-				<<(*i)<<"\""<<std::endl;
+	for (const std::string &node_name: unallocatable_contents) {
+		errorstream << "correctBlockNodeIds(): IGNORING ERROR: "
+				<< "Could not allocate global id for node name \""
+				<< node_name << "\"" << std::endl;
 	}
 }