[project @ 2002-11-28 10:04:52 by simonpj]

[ghc-hetmet.git] / ghc / compiler / rename / RnTypes.lhs

diff --git a/ghc/compiler/rename/RnTypes.lhs b/ghc/compiler/rename/RnTypes.lhs
index 88963e1..421378a 100644 (file)
--- a/ghc/compiler/rename/RnTypes.lhs
+++ b/ghc/compiler/rename/RnTypes.lhs
@@ -8,7 +8,7 @@ module RnTypes ( rnHsType, rnContext,
                 rnHsSigType, rnHsTypeFVs, rnHsSigTypeFVs, 
                 rnPat, rnPats, rnPatsAndThen,  -- Here because it's not part 
                 rnOverLit, litFVs,             -- of any mutual recursion      
-                precParseErr, sectionPrecErr, dupFieldErr, patSigErr
+                precParseErr, sectionPrecErr, dupFieldErr, patSigErr, checkTupSize
   ) where
 
 import CmdLineOpts     ( DynFlag(Opt_WarnMisc, Opt_WarnUnusedMatches, Opt_GlasgowExts) )
@@ -27,6 +27,7 @@ import TcRnMonad
 import PrelNames( cCallishClassKeys, eqStringName, eqClassName, ordClassName, 
                  negateName, minusName, lengthPName, indexPName, plusIntegerName, fromIntegerName,
                  timesIntegerName, ratioDataConName, fromRationalName, cCallableClassName )
+import Constants       ( mAX_TUPLE_SIZE )
 import TysWiredIn      ( intTyCon )
 import TysPrim         ( charPrimTyCon, addrPrimTyCon, intPrimTyCon, 
                          floatPrimTyCon, doublePrimTyCon )
@@ -402,10 +403,12 @@ rnPat (PArrPat pats _)
     implicit_fvs = mkFVs [lengthPName, indexPName]
 
 rnPat (TuplePat pats boxed)
-  = rnPats pats                        `thenM` \ (patslist, fvs) ->
+  = checkTupSize tup_size      `thenM_`
+    rnPats pats                        `thenM` \ (patslist, fvs) ->
     returnM (TuplePat patslist boxed, fvs `addOneFV` tycon_name)
   where
-    tycon_name = tupleTyCon_name boxed (length pats)
+    tup_size   = length pats
+    tycon_name = tupleTyCon_name boxed tup_size
 
 rnPat (TypePat name) =
     rnHsTypeFVs (text "In a type pattern") name        `thenM` \ (name', fvs) ->
@@ -545,8 +548,16 @@ rnOverLit (HsFractional i _)
 %*                                                     *
 %*********************************************************
 
-\end{code}
 \begin{code}
+checkTupSize :: Int -> RnM ()
+checkTupSize tup_size
+  | tup_size <= mAX_TUPLE_SIZE 
+  = returnM ()
+  | otherwise                 
+  = addErr (sep [ptext SLIT("A") <+> int tup_size <> ptext SLIT("-tuple is too large for GHC"),
+                nest 2 (parens (ptext SLIT("max size is") <+> int mAX_TUPLE_SIZE)),
+                nest 2 (ptext SLIT("Workaround: use nested tuples or define a data type"))])
+
 forAllWarn doc ty tyvar
   = ifOptM Opt_WarnUnusedMatches       $
     getModeRn                          `thenM` \ mode ->