Result of match_kind, am I reading this correctly?

[Twan van Laarhoven]

Hello,

While fixing 'unused binding' warnings in compiler/types/Unify.lhs I came across 
the following in the function match (line 163):

	    -> do { subst1 <- match_kind menv subst tv1 ty2
		  ; return (extendVarEnv subst tv1' ty2) }

Since the new substitution is not used, this is equivalent to

	    -> do { match_kind menv subst tv1 ty2
		  ; return (extendVarEnv subst tv1' ty2) }

Is this correct?

Twan