New interface to Typer: the function TypeName() returns a more readable type name

operand-list.go

@@ -62,6 +62,10 @@ func (ls *ListType) String() string {
 	return ls.ToString(0)
 }
 
+func (ls *ListType) TypeName() string {
+	return "list"
+}
+
 func (list *ListType) indexDeepCmp(target any) (index int) {
 	index = -1
 	for i, item := range *list {