bomb_out sig_tv1 sig_tv2
= failWithTc (ptext SLIT("Quantified type variable") <+> quotes (ppr tidy_tv1)
<+> ptext SLIT("is unified with another quantified type variable")
- <+> ppr tidy_tv2)
+ <+> quotes (ppr tidy_tv2))
where
(env1, tidy_tv1) = tidyOpenTyVar emptyTidyEnv sig_tv1
(_env2, tidy_tv2) = tidyOpenTyVar env1 sig_tv2