Fix a bug in Lint (which wrongly complained when compiling Data.Sequence with -02)

[ghc-hetmet.git] / compiler / coreSyn / CoreLint.lhs

diff --git a/compiler/coreSyn/CoreLint.lhs b/compiler/coreSyn/CoreLint.lhs
index 394140d..59c52da 100644 (file)
--- a/compiler/coreSyn/CoreLint.lhs
+++ b/compiler/coreSyn/CoreLint.lhs
@@ -1,7 +1,9 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
 %
-\section[CoreLint]{A ``lint'' pass to check for Core correctness}
+
+A ``lint'' pass to check for Core correctness
 
 \begin{code}
 module CoreLint (
@@ -13,43 +15,32 @@ module CoreLint (
 #include "HsVersions.h"
 
 import CoreSyn
-import CoreFVs         ( idFreeVars )
-import CoreUtils       ( findDefault, exprOkForSpeculation, coreBindsSize )
+import CoreFVs
+import CoreUtils
 import Bag
-import Literal         ( literalType )
-import DataCon         ( dataConRepType, dataConTyCon, dataConWorkId )
-import TysWiredIn      ( tupleCon )
-import Var             ( Var, Id, TyVar, isCoVar, idType, tyVarKind, 
-                         mustHaveLocalBinding, setTyVarKind, setIdType  )
-import VarEnv           ( lookupInScope )
+import Literal
+import DataCon
+import TysWiredIn
+import Var
+import VarEnv
 import VarSet
-import Name            ( getSrcLoc )
+import Name
 import PprCore
-import ErrUtils                ( dumpIfSet_core, ghcExit, Message, showPass,
-                         mkLocMessage, debugTraceMsg )
-import SrcLoc          ( SrcLoc, noSrcLoc, mkSrcSpan )
-import Type            ( Type, tyVarsOfType, coreEqType,
-                         splitFunTy_maybe, mkTyVarTys,
-                         splitForAllTy_maybe, splitTyConApp_maybe,
-                         isUnLiftedType, typeKind, mkForAllTy, mkFunTy,
-                         isUnboxedTupleType, isSubKind,
-                         substTyWith, emptyTvSubst, extendTvInScope, 
-                         TvSubst, TvSubstEnv, mkTvSubst, setTvSubstEnv, substTy,
-                         extendTvSubst, composeTvSubst, substTyVarBndr, isInScope,
-                         getTvSubstEnv, getTvInScope, mkTyVarTy )
-import Coercion         ( Coercion, coercionKind, coercionKindPredTy )
-import TyCon           ( isPrimTyCon, isNewTyCon )
-import BasicTypes      ( RecFlag(..), Boxity(..), isNonRec )
-import StaticFlags     ( opt_PprStyle_Debug )
-import DynFlags                ( DynFlags, DynFlag(..), dopt )
+import ErrUtils
+import SrcLoc
+import Type
+import Coercion
+import TyCon
+import BasicTypes
+import StaticFlags
+import DynFlags
 import Outputable
 
 #ifdef DEBUG
 import Util             ( notNull )
 #endif
 
-import Maybe
-
+import Data.Maybe
 \end{code}
 
 %************************************************************************
@@ -378,8 +369,8 @@ The basic version of these functions checks that the argument is a
 subtype of the required type, as one would expect.
 
 \begin{code}
-lintCoreArgs :: Type -> [CoreArg] -> LintM Type
-lintCoreArg  :: Type -> CoreArg   -> LintM Type
+lintCoreArgs :: OutType -> [CoreArg] -> LintM OutType
+lintCoreArg  :: OutType -> CoreArg   -> LintM OutType
 -- First argument has already had substitution applied to it
 \end{code}
 
@@ -407,6 +398,7 @@ lintCoreArg fun_ty arg =
 
 \begin{code}
 -- Both args have had substitution applied
+lintTyApp :: OutType -> OutType -> LintM OutType
 lintTyApp ty arg_ty 
   = case splitForAllTy_maybe ty of
       Nothing -> addErrL (mkTyAppMsg ty arg_ty)
@@ -416,12 +408,6 @@ lintTyApp ty arg_ty
                ; checkKinds tyvar arg_ty
                ; return (substTyWith [tyvar] [arg_ty] body) }
 
-lintTyApps fun_ty [] = return fun_ty
-
-lintTyApps fun_ty (arg_ty : arg_tys) = 
-  do { fun_ty' <- lintTyApp fun_ty arg_ty
-     ; lintTyApps fun_ty' arg_tys }
-
 checkKinds tyvar arg_ty
        -- Arg type might be boxed for a function with an uncommitted
        -- tyvar; notably this is used so that we can give
@@ -503,7 +489,9 @@ lintCoreAlt scrut_ty alt_ty alt@(DataAlt con, args, rhs)
   = addLoc (CaseAlt alt) $  do
     {   -- First instantiate the universally quantified 
        -- type variables of the data constructor
-      con_payload_ty <- lintCoreArgs (dataConRepType con) (map Type tycon_arg_tys)
+       -- We've already check
+      checkL (tycon == dataConTyCon con) (mkBadConMsg tycon con)
+    ; let con_payload_ty = applyTys (dataConRepType con) tycon_arg_tys
 
        -- And now bring the new binders into scope
     ; lintBinders args $ \ args -> do
@@ -797,7 +785,6 @@ mkScrutMsg var var_ty scrut_ty subst
          text "Scrutinee type:" <+> ppr scrut_ty,
      hsep [ptext SLIT("Current TV subst"), ppr subst]]
 
-
 mkNonDefltMsg e
   = hang (text "Case expression with DEFAULT not at the beginnning") 4 (ppr e)
 mkNonIncreasingAltsMsg e
@@ -807,6 +794,14 @@ nonExhaustiveAltsMsg :: CoreExpr -> Message
 nonExhaustiveAltsMsg e
   = hang (text "Case expression with non-exhaustive alternatives") 4 (ppr e)
 
+mkBadConMsg :: TyCon -> DataCon -> Message
+mkBadConMsg tycon datacon
+  = vcat [
+       text "In a case alternative, data constructor isn't in scrutinee type:",
+       text "Scrutinee type constructor:" <+> ppr tycon,
+       text "Data con:" <+> ppr datacon
+    ]
+
 mkBadPatMsg :: Type -> Type -> Message
 mkBadPatMsg con_result_ty scrut_ty
   = vcat [