Fix dependency information for RULES
A SpecInfo (inside IdInfo) keeps track of the free variables of a RULE so that the occurrency analyser knows about its dependencies. Previously it was only tracking the *rhs* free vars, but it should really include the *lhs* ones too. See Note [Rule dependency info] in IdInfo. This fixes a WARNING when compiling some libraries.
Showing with 36 additions and 15 deletions