- much more efficiently if @<test> is @|eq|, @|eql|, @|equal|, or @|equalp|
- (because it can use hash-tables).
+ much more efficiently if @<test> is @|eq|, @|eql|, @|equal|, or @|equalp|,
+ because it can use hash-tables. (The generic implementation for lists is
+ especially inefficient.)