Fix check of rhs of type family instances (#2157)

[ghc-hetmet.git] / compiler / typecheck / TcSplice.lhs

diff --git a/compiler/typecheck/TcSplice.lhs b/compiler/typecheck/TcSplice.lhs
index 27656c9..60d6a6b 100644 (file)
--- a/compiler/typecheck/TcSplice.lhs
+++ b/compiler/typecheck/TcSplice.lhs
@@ -157,6 +157,7 @@ The predicate we use is TcEnv.thTopLevelId.
 %************************************************************************
 
 \begin{code}
+tcBracket     :: HsBracket Name -> BoxyRhoType -> TcM (LHsExpr TcId)
 tcSpliceDecls :: LHsExpr Name -> TcM [LHsDecl RdrName]
 tcSpliceExpr  :: HsSplice Name -> BoxyRhoType -> TcM (HsExpr TcId)
 kcSpliceType  :: HsSplice Name -> TcM (HsType Name, TcKind)
@@ -166,8 +167,10 @@ runQuasiQuoteExpr :: HsQuasiQuote Name -> TcM (LHsExpr RdrName)
 runQuasiQuotePat  :: HsQuasiQuote Name -> TcM (LPat RdrName)
 
 #ifndef GHCI
-tcSpliceExpr _ e _ = pprPanic "Cant do tcSpliceExpr without GHCi" (ppr e)
-tcSpliceDecls e    = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e)
+tcBracket     x _ = pprPanic "Cant do tcBracket without GHCi"     (ppr x)
+tcSpliceExpr  e   = pprPanic "Cant do tcSpliceExpr without GHCi"  (ppr e)
+tcSpliceDecls x   = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr x)
+kcSpliceType  x   = pprPanic "Cant do kcSpliceType without GHCi"  (ppr x)
 
 runQuasiQuoteExpr q = pprPanic "Cant do runQuasiQuoteExpr without GHCi" (ppr q)
 runQuasiQuotePat  q = pprPanic "Cant do runQuasiQuotePat without GHCi" (ppr q)
@@ -193,7 +196,6 @@ Desugared:  f = do { s7 <- g Int 3
                       ; return (ConE "Data.Maybe.Just" s7) }
 
 \begin{code}
-tcBracket :: HsBracket Name -> BoxyRhoType -> TcM (LHsExpr TcId)
 tcBracket brack res_ty = do
    level <- getStage
    case bracketOK level of {
@@ -720,25 +722,29 @@ reify th_name
 
 lookupThName :: TH.Name -> TcM Name
 lookupThName th_name@(TH.Name occ flavour)
-  =  do { let rdr_name = thRdrName guessed_ns occ_str flavour
-
-       -- Repeat much of lookupOccRn, becase we want
-       -- to report errors in a TH-relevant way
-       ; rdr_env <- getLocalRdrEnv
-       ; case lookupLocalRdrEnv rdr_env rdr_name of
-           Just name -> return name
-           Nothing | not (isSrcRdrName rdr_name)       -- Exact, Orig
-                   -> lookupImportedName rdr_name
-                   | otherwise                         -- Unqual, Qual
-                   -> do { mb_name <- lookupSrcOcc_maybe rdr_name
-                         ; case mb_name of
-                             Just name -> return name
-                             Nothing   -> failWithTc (notInScope th_name) }
-       }
+  =  do { mb_ns <- mapM lookup [ thRdrName gns occ_str flavour 
+                              | gns <- guessed_nss]
+       ; case catMaybes mb_ns of
+           []    -> failWithTc (notInScope th_name)
+           (n:_) -> return n } -- Pick the first that works
+                               -- E.g. reify (mkName "A") will pick the class A
+                               --      in preference to the data constructor A
   where
-       -- guessed_ns is the name space guessed from looking at the TH name
-    guessed_ns | isLexCon (mkFastString occ_str) = OccName.dataName
-              | otherwise                       = OccName.varName
+    lookup rdr_name
+       = do {  -- Repeat much of lookupOccRn, becase we want
+               -- to report errors in a TH-relevant way
+            ; rdr_env <- getLocalRdrEnv
+            ; case lookupLocalRdrEnv rdr_env rdr_name of
+                Just name -> return (Just name)
+                Nothing | not (isSrcRdrName rdr_name)  -- Exact, Orig
+                        -> do { name <- lookupImportedName rdr_name
+                              ; return (Just name) }
+                        | otherwise                    -- Unqual, Qual
+                        -> lookupSrcOcc_maybe rdr_name }
+
+       -- guessed_ns are the name spaces guessed from looking at the TH name
+    guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName,  OccName.dataName]
+               | otherwise                       = [OccName.varName, OccName.tvName]
     occ_str = TH.occString occ
 
 tcLookupTh :: Name -> TcM TcTyThing