diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index 7953c274fa5a43..fb45873e5a86eb 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -2514,7 +2514,7 @@ fn (mut c Checker) spawn_expr(mut node ast.SpawnExpr) ast.Type {
 			node.call_expr.or_block.pos)
 	}
 	// Make sure there are no mutable arguments
-	for mut arg in node.call_expr.args {
+	for arg in node.call_expr.args {
 		if arg.is_mut && !arg.typ.is_ptr() {
 			if c.table.final_sym(arg.typ).kind == .array {
 				// allow mutable []array to be passed as mut