diff options
| -rw-r--r-- | compiler/GHC/Tc/Solver/Rewrite.hs | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/compiler/GHC/Tc/Solver/Rewrite.hs b/compiler/GHC/Tc/Solver/Rewrite.hs index 3f2f8f35ce..b7573e7f09 100644 --- a/compiler/GHC/Tc/Solver/Rewrite.hs +++ b/compiler/GHC/Tc/Solver/Rewrite.hs @@ -865,8 +865,10 @@ rewrite_exact_fam_app tc tys { Just (redn, fr@(_, inert_eq_rel)) | fr `eqCanRewriteFR` (flavour, eq_rel) -> - do { traceRewriteM "rewrite family application with inert" - (ppr tc <+> ppr xis $$ ppr redn) + do { traceRewriteM "rewrite family application with inert" $ + vcat [ ppr tc <+> ppr xis + , ppUnless (flavour == Derived) (ppr redn) ] + -- Deriveds have no evidence, so we can't print the reduction ; finish True (homogenise downgraded_redn) } -- this will sometimes duplicate an inert in the cache, -- but avoiding doing so had no impact on performance, and |