[commit: ghc] master: A little more debug tracing (24d3276)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/24d3276df62b52bdf720f4789ff9ddbbb7c02cec/ghc

>---------------------------------------------------------------

commit 24d3276df62b52bdf720f4789ff9ddbbb7c02cec
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Thu Apr 21 14:30:36 2016 +0100

    A little more debug tracing


>---------------------------------------------------------------

24d3276df62b52bdf720f4789ff9ddbbb7c02cec
 compiler/typecheck/TcCanonical.hs | 2 +-
 compiler/typecheck/TcFlatten.hs   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/compiler/typecheck/TcCanonical.hs b/compiler/typecheck/TcCanonical.hs
index 4ff046f..cde6478 100644
--- a/compiler/typecheck/TcCanonical.hs
+++ b/compiler/typecheck/TcCanonical.hs
@@ -532,7 +532,7 @@ can_eq_nc
    -> TcS (StopOrContinue Ct)
 can_eq_nc flat ev eq_rel ty1 ps_ty1 ty2 ps_ty2
   = do { traceTcS "can_eq_nc" $
-         vcat [ ppr ev, ppr eq_rel, ppr ty1, ppr ps_ty1, ppr ty2, ppr ps_ty2 ]
+         vcat [ ppr flat, ppr ev, ppr eq_rel, ppr ty1, ppr ps_ty1, ppr ty2, ppr ps_ty2 ]
        ; rdr_env <- getGlobalRdrEnvTcS
        ; fam_insts <- getFamInstEnvs
        ; can_eq_nc' flat rdr_env fam_insts ev eq_rel ty1 ps_ty1 ty2 ps_ty2 }
diff --git a/compiler/typecheck/TcFlatten.hs b/compiler/typecheck/TcFlatten.hs
index 6737106..6bac122 100644
--- a/compiler/typecheck/TcFlatten.hs
+++ b/compiler/typecheck/TcFlatten.hs
@@ -1312,7 +1312,8 @@ flatten_tyvar1 tv
        ; case mb_ty of
            Just ty -> do { traceFlat "Following filled tyvar" (ppr tv <+> equals <+> ppr ty)
                          ; return (FTRFollowed ty (mkReflCo role ty)) } ;
-           Nothing -> do { fr <- getFlavourRole
+           Nothing -> do { traceFlat "Unfilled tyvar" (ppr tv)
+                         ; fr <- getFlavourRole
                          ; flatten_tyvar2  tv fr } }
 
 flatten_tyvar2 :: TcTyVar -> CtFlavourRole -> FlatM FlattenTvResult