diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index e3c55870c..3c998fc44 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -442,10 +442,11 @@ gb_internal bool find_or_generate_polymorphic_procedure(CheckerContext *old_c, E
 	auto *found = map_get(&info->gen_procs, base_entity->identifier.load());
 	if (found) {
 		gen_procs = *found;
-		MUTEX_GUARD(&gen_procs->mutex);
+		mutex_lock(&gen_procs->mutex); // @local-mutex
 		for (Entity *other : gen_procs->procs) {
 			Type *pt = base_type(other->type);
 			if (are_types_identical(pt, final_proc_type)) {
+				mutex_unlock(&gen_procs->mutex); // @local-mutex
 				// @@GPM ////////////////////////////
 				mutex_unlock(&info->gen_procs_mutex);
 				/////////////////////////////////////
@@ -456,6 +457,7 @@ gb_internal bool find_or_generate_polymorphic_procedure(CheckerContext *old_c, E
 				return true;
 			}
 		}
+		mutex_unlock(&gen_procs->mutex); // @local-mutex
 	} else {
 		gen_procs = gb_alloc_item(permanent_allocator(), GenProcsData);
 		gen_procs->procs.allocator = heap_allocator();
@@ -481,10 +483,12 @@ gb_internal bool find_or_generate_polymorphic_procedure(CheckerContext *old_c, E
 			return false;
 		}
 
-		MUTEX_GUARD(&gen_procs->mutex);
+		mutex_lock(&gen_procs->mutex); // @local-mutex
 		for (Entity *other : gen_procs->procs) {
 			Type *pt = base_type(other->type);
 			if (are_types_identical(pt, final_proc_type)) {
+				mutex_unlock(&gen_procs->mutex); // @local-mutex
+
 				if (poly_proc_data) {
 					poly_proc_data->gen_entity = other;
 				}
@@ -507,6 +511,7 @@ gb_internal bool find_or_generate_polymorphic_procedure(CheckerContext *old_c, E
 				return true;
 			}
 		}
+		mutex_unlock(&gen_procs->mutex); // @local-mutex
 	}
 
 
@@ -566,9 +571,9 @@ gb_internal bool find_or_generate_polymorphic_procedure(CheckerContext *old_c, E
 		}
 	}
 
-	MUTEX_GUARD_BLOCK(&gen_procs->mutex) {
+	mutex_lock(&gen_procs->mutex); // @local-mutex
 		array_add(&gen_procs->procs, entity);
-	}
+	mutex_unlock(&gen_procs->mutex); // @local-mutex
 
 	ProcInfo *proc_info = gb_alloc_item(permanent_allocator(), ProcInfo);
 	proc_info->file  = file;