[project @ 2003-05-29 13:22:51 by simonpj]

n+k patterns should be in Integral, according to the Report

diff --git a/ghc/compiler/rename/RnTypes.lhs b/ghc/compiler/rename/RnTypes.lhs
index 19cec11..121cf07 100644 (file)
--- a/ghc/compiler/rename/RnTypes.lhs
+++ b/ghc/compiler/rename/RnTypes.lhs
@@ -24,7 +24,7 @@ import RnEnv  ( lookupOccRn, lookupBndrRn, lookupSyntaxName, lookupGlobalOccRn,
                  bindPatSigTyVarsFV, bindLocalsFV, warnUnusedMatches )
 import TcRnMonad
 
-import PrelNames( cCallishClassKeys, eqStringName, eqClassName, ordClassName, 
+import PrelNames( cCallishClassKeys, eqStringName, eqClassName, integralClassName, 
                  negateName, minusName, lengthPName, indexPName, plusIntegerName, fromIntegerName,
                  timesIntegerName, ratioDataConName, fromRationalName, cCallableClassName )
 import Constants       ( mAX_TUPLE_SIZE )
@@ -373,7 +373,8 @@ rnPat (NPlusKPatIn name lit _)
     lookupBndrRn name                  `thenM` \ name' ->
     lookupSyntaxName minusName         `thenM` \ (minus, fvs2) ->
     returnM (NPlusKPatIn name' lit' minus, 
-             fvs1 `plusFV` fvs2 `addOneFV` ordClassName)
+             fvs1 `plusFV` fvs2 `addOneFV` integralClassName)
+       -- The Report says that n+k patterns must be in Integral
 
 rnPat (LazyPat pat)
   = rnPat pat          `thenM` \ (pat', fvs) ->

diff --git a/ghc/compiler/typecheck/TcPat.lhs b/ghc/compiler/typecheck/TcPat.lhs
index c353085..63b7ac9 100644 (file)
--- a/ghc/compiler/typecheck/TcPat.lhs
+++ b/ghc/compiler/typecheck/TcPat.lhs
@@ -35,7 +35,8 @@ import TcMonoType     ( tcHsSigType, UserTypeCtxt(..) )
 import TysWiredIn      ( stringTy )
 import CmdLineOpts     ( opt_IrrefutableTuples )
 import DataCon         ( DataCon, dataConFieldLabels, dataConSourceArity )
-import PrelNames       ( eqStringName, eqName, geName, negateName, minusName, cCallableClassName )
+import PrelNames       ( eqStringName, eqName, geName, negateName, minusName, 
+                         integralClassName, cCallableClassName )
 import BasicTypes      ( isBoxed )
 import Bag
 import Outputable
@@ -308,6 +309,12 @@ tcPat tc_bndr pat@(NPlusKPatIn name lit@(HsIntegral i _) minus_name) pat_ty
        -- The '-' part is re-mappable syntax
     tcSyntaxName origin pat_ty' minusName minus_name   `thenM` \ (minus_expr, _) ->
 
+       -- The Report says that n+k patterns must be in Integral
+       -- We may not want this when using re-mappable syntax, though (ToDo?)
+    tcLookupClass integralClassName                    `thenM` \ icls ->
+    newDicts origin [mkClassPred icls [pat_ty']]       `thenM` \ dicts ->
+    extendLIEs dicts                                   `thenM_`
+    
     returnM (NPlusKPatOut bndr_id i 
                           (SectionR (HsVar ge) over_lit_expr)
                           (SectionR minus_expr over_lit_expr),