[project @ 1999-03-02 17:18:27 by sof]

ppr bugfix for dcons that are locally qualified
(omit braces around context if there isn't one.)

diff --git a/ghc/compiler/main/MkIface.lhs b/ghc/compiler/main/MkIface.lhs
index 5307d23..4a41a10 100644 (file)
--- a/ghc/compiler/main/MkIface.lhs
+++ b/ghc/compiler/main/MkIface.lhs
@@ -42,11 +42,12 @@ import CoreSyn              ( CoreExpr, CoreBind, Bind(..) )
 import CoreUtils       ( exprSomeFreeVars )
 import CoreUnfold      ( calcUnfoldingGuidance, UnfoldingGuidance(..), 
                          Unfolding, okToUnfoldInHiFile )
+import Module          ( moduleString, pprModule, pprModuleBoot )
 import Name            ( isLocallyDefined, isWiredInName, nameRdrName, nameModule,
                          isExported,
                          Name, NamedThing(..)
                        )
-import OccName         ( OccName, pprOccName, moduleString, pprModule, pprModuleBoot )
+import OccName         ( OccName, pprOccName )
 import TyCon           ( TyCon, getSynTyConDefn, isSynTyCon, isNewTyCon, isAlgTyCon,
                          tyConTheta, tyConTyVars, tyConDataCons
                        )
@@ -543,7 +544,8 @@ ppr_decl_context []    = empty
 ppr_decl_context theta = pprIfaceTheta theta <+> ptext SLIT(" =>")
 
 pprIfaceTheta :: ThetaType -> SDoc     -- Use braces rather than parens in interface files
-pprIfaceTheta theta =  braces (hsep (punctuate comma [pprConstraint c tys | (c,tys) <- theta]))
+pprIfaceTheta []    = empty
+pprIfaceTheta theta = braces (hsep (punctuate comma [pprConstraint c tys | (c,tys) <- theta]))
 \end{code}
 
 %************************************************************************