diff --git a/src/list.c b/src/list.c
index 5c2f60e..14a31bc 100644
--- a/src/list.c
+++ b/src/list.c
@@ -1194,6 +1194,9 @@
 	    else
 		clear_tv(&tv);
 	}
+	// Legacy Vim script allowed a space before the comma.
+	if (!vim9script)
+	    *arg = skipwhite(*arg);
 
 	// the comma must come after the value
 	had_comma = **arg == ',';