addLoc :: LintLocInfo -> LintM a -> LintM a
addLoc extra_loc m = LintM $ \loc scope errs
   -> unLintM m (extra_loc:loc) scope errs
addLoc :: LintLocInfo -> LintM a -> LintM a
addLoc extra_loc m = LintM $ \loc scope errs
   -> unLintM m (extra_loc:loc) scope errs
addLoc extra_loc m = LintM $ \loc scope errs
   -> unLintM m (extra_loc:loc) scope errs