Remove useless hypothesis from context

Question

Sometimes I have a hypothesis in my proof context that I've used already, and now I know I won't need it anymore. In order to keep my context tidy while I work on the proof, I'd like to remove this hypothesis. Is there a tactic to do that?

Answer 1

If you use the SSReflect proof language, you can clear an hypothesis H by using the {H} notation. This can be done inline after many tactics such as move or rewrite, as in:

rewrite foo bar => {H}

Answer 2

Use the clear tactic:

Before:

1 goal
  
  stuff ...
  H : T
  ============================
  goal

clear H.

After:

1 goal
  
  stuff ...
  ============================
  goal