Kind sigs in associated data/newtype family decls may be omitted

[ghc-hetmet.git] / compiler / main / HscTypes.lhs

diff --git a/compiler/main/HscTypes.lhs b/compiler/main/HscTypes.lhs
index a0e4857..a76ec5a 100644 (file)
--- a/compiler/main/HscTypes.lhs
+++ b/compiler/main/HscTypes.lhs
@@ -209,9 +209,15 @@ data TargetId
 pprTarget :: Target -> SDoc
 pprTarget (Target id _) = pprTargetId id
 
+instance Outputable Target where
+    ppr = pprTarget
+
 pprTargetId (TargetModule m) = ppr m
 pprTargetId (TargetFile f _) = text f
 
+instance Outputable TargetId where
+    ppr = pprTargetId
+
 type HomePackageTable  = ModuleNameEnv HomeModInfo
        -- Domain = modules in the home package
        -- "home" package name cached here for convenience
@@ -295,12 +301,15 @@ hptRules hsc_env deps
     , mod /= moduleName gHC_PRIM
 
        -- Look it up in the HPT
-    , let mod_info = case lookupUFM hpt mod of
-                       Nothing -> pprPanic "hptRules" (ppr mod <+> ppr deps)
-                       Just x  -> x
+    , let rules = case lookupUFM hpt mod of
+                   Just info -> md_rules (hm_details info)
+                   Nothing -> pprTrace "WARNING in hptRules" msg [] 
+         msg = vcat [ptext SLIT("missing module") <+> ppr mod,
+                     ptext SLIT("Probable cause: out-of-date interface files")]
+                       -- This really shouldn't happen, but see Trac #962
 
        -- And get its dfuns
-    , rule <- md_rules (hm_details mod_info) ]
+    , rule <- rules ]
 \end{code}
 
 %************************************************************************