[commit: ghc] master: Remove unnecessary isTyVar tests in TcType (a0899b2)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/a0899b2f66a4102a7cf21569889381446ce63833/ghc

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

commit a0899b2f66a4102a7cf21569889381446ce63833
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Tue Mar 1 17:05:56 2016 +0000

    Remove unnecessary isTyVar tests in TcType
    
    These extra tests were added by Richard when he had CoVars floating
    around in places where previously only TyVars had been.  But
    fortunately those days are gone, so these tests are unnecessary,
    and are slowing GHC down.
    
    Let's remove them.


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

a0899b2f66a4102a7cf21569889381446ce63833
 compiler/typecheck/TcType.hs | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/compiler/typecheck/TcType.hs b/compiler/typecheck/TcType.hs
index 73a46ae..40821e5 100644
--- a/compiler/typecheck/TcType.hs
+++ b/compiler/typecheck/TcType.hs
@@ -860,7 +860,6 @@ isTouchableOrFmv ctxt_tclvl tv
 
 isTouchableMetaTyVar :: TcLevel -> TcTyVar -> Bool
 isTouchableMetaTyVar ctxt_tclvl tv
-  | isTyVar tv
   = ASSERT2( isTcTyVar tv, ppr tv )
     case tcTyVarDetails tv of
       MetaTv { mtv_tclvl = tv_tclvl }
@@ -868,16 +867,13 @@ isTouchableMetaTyVar ctxt_tclvl tv
                     ppr tv $$ ppr tv_tclvl $$ ppr ctxt_tclvl )
            tv_tclvl `sameDepthAs` ctxt_tclvl
       _ -> False
-  | otherwise = False
 
 isFloatedTouchableMetaTyVar :: TcLevel -> TcTyVar -> Bool
 isFloatedTouchableMetaTyVar ctxt_tclvl tv
-  | isTyVar tv
   = ASSERT2( isTcTyVar tv, ppr tv )
     case tcTyVarDetails tv of
       MetaTv { mtv_tclvl = tv_tclvl } -> tv_tclvl `strictlyDeeperThan` ctxt_tclvl
       _ -> False
-  | otherwise = False
 
 isImmutableTyVar :: TyVar -> Bool
 isImmutableTyVar tv
@@ -892,12 +888,10 @@ isTyConableTyVar tv
         -- True of a meta-type variable that can be filled in
         -- with a type constructor application; in particular,
         -- not a SigTv
-  | isTyVar tv
   = ASSERT2( isTcTyVar tv, ppr tv )
     case tcTyVarDetails tv of
         MetaTv { mtv_info = SigTv } -> False
         _                           -> True
-  | otherwise = True
 
 isFmvTyVar tv
   = ASSERT2( isTcTyVar tv, ppr tv )
@@ -927,20 +921,16 @@ isSkolemTyVar tv
         _other    -> True
 
 isOverlappableTyVar tv
-  | isTyVar tv
   = ASSERT2( isTcTyVar tv, ppr tv )
     case tcTyVarDetails tv of
         SkolemTv overlappable -> overlappable
         _                     -> False
-  | otherwise = False
 
 isMetaTyVar tv
-  | isTyVar tv
   = ASSERT2( isTcTyVar tv, ppr tv )
     case tcTyVarDetails tv of
         MetaTv {} -> True
         _         -> False
-  | otherwise = False
 
 -- isAmbiguousTyVar is used only when reporting type errors
 -- It picks out variables that are unbound, namely meta
@@ -948,12 +938,10 @@ isMetaTyVar tv
 -- RtClosureInspect.zonkRTTIType.  These are "ambiguous" in
 -- the sense that they stand for an as-yet-unknown type
 isAmbiguousTyVar tv
-  | isTyVar tv
   = case tcTyVarDetails tv of
         MetaTv {}     -> True
         RuntimeUnk {} -> True
         _             -> False
-  | otherwise = False
 
 isMetaTyVarTy :: TcType -> Bool
 isMetaTyVarTy (TyVarTy tv) = isMetaTyVar tv