[project @ 1997-05-26 04:55:34 by sof]

Updated imports; improved error msgs; coercion handling

diff --git a/ghc/compiler/coreSyn/CoreLint.lhs b/ghc/compiler/coreSyn/CoreLint.lhs
index 474f505..182c7c2 100644 (file)
--- a/ghc/compiler/coreSyn/CoreLint.lhs
+++ b/ghc/compiler/coreSyn/CoreLint.lhs
@@ -13,13 +13,14 @@ module CoreLint (
 
 IMP_Ubiq()
 
+import CmdLineOpts      ( opt_PprUserLength )
 import CoreSyn
 
 import Bag
 import Kind            ( hasMoreBoxityInfo, Kind{-instance-}, 
                          isTypeKind, isBoxedTypeKind {- TEMP --SOF -} )
 import Literal         ( literalType, Literal{-instance-} )
-import Id              ( idType, isBottomingId, dataConRepType,
+import Id              ( idType, isBottomingId, dataConRepType, isDataCon, isNewCon,
                          dataConArgTys, GenId{-instances-},
                          emptyIdSet, mkIdSet, intersectIdSets,
                          unionIdSets, elementOfIdSet, SYN_IE(IdSet),
@@ -28,9 +29,8 @@ import Id             ( idType, isBottomingId, dataConRepType,
 import Maybes          ( catMaybes )
 import Name            ( isLocallyDefined, getSrcLoc, Name{-instance NamedThing-},
                          NamedThing(..) )
-import Outputable      ( Outputable(..){-instance * []-} )
 import PprCore
-import PprStyle                ( PprStyle(..) )
+import Outputable      ( PprStyle(..), Outputable(..) )
 import PprType         ( GenType, GenTyVar, TyCon )
 import Pretty
 import PrimOp          ( primOpType, PrimOp(..) )
@@ -42,9 +42,8 @@ import Type           ( mkFunTy,getFunTy_maybe,mkForAllTy,mkForAllTys,getForAllTy_maybe,
                          isPrimType,typeKind,instantiateTy,splitSigmaTy,
                          mkForAllUsageTy,getForAllUsageTy,instantiateUsage,
                          maybeAppDataTyConExpandingDicts, eqTy, SYN_IE(Type)
---                       ,expandTy -- ToDo:rm
                        )
-import TyCon           ( isPrimTyCon )
+import TyCon           ( isPrimTyCon, isDataTyCon )
 import TyVar           ( tyVarKind, GenTyVar{-instances-} )
 import Unique          ( Unique )
 import Usage           ( GenUsage, SYN_IE(Usage) )
@@ -128,7 +127,7 @@ lintUnfolding locn expr
       Nothing  -> Just expr
       Just msg ->
         pprTrace "WARNING: Discarded bad unfolding from interface:\n"
-       (vcat [msg PprForUser,
+       (vcat [msg (PprForUser opt_PprUserLength),
                   ptext SLIT("*** Bad unfolding ***"),
                   ppr PprDebug expr,
                   ptext SLIT("*** End unfolding ***")])
@@ -189,8 +188,9 @@ lintCoreExpr :: CoreExpr -> LintM (Maybe Type)      -- Nothing if error found
 lintCoreExpr (Var var) = checkInScope var `seqL` returnL (Just (idType var))
 lintCoreExpr (Lit lit) = returnL (Just (literalType lit))
 lintCoreExpr (SCC _ expr) = lintCoreExpr expr
-lintCoreExpr (Coerce _ ty expr)
-  = lintCoreExpr expr `seqL` returnL (Just ty)
+lintCoreExpr e@(Coerce coercion ty expr)
+  = lintCoercion e coercion    `seqL`
+    lintCoreExpr expr `seqL` returnL (Just ty)
 
 lintCoreExpr (Let binds body)
   = lintCoreBinding binds `thenL` \binders ->
@@ -201,7 +201,8 @@ lintCoreExpr (Let binds body)
        (addInScopeVars binders (lintCoreExpr body))
 
 lintCoreExpr e@(Con con args)
-  = lintCoreArgs {-False-} e (dataConRepType con) args
+  = checkL (isDataCon con) (mkConErrMsg e)     `seqL`
+    lintCoreArgs {-False-} e (dataConRepType con) args
     -- Note: we don't check for primitive types in these arguments
 
 lintCoreExpr e@(Prim op args)
@@ -287,8 +288,7 @@ lintCoreArg e ty a@(TyArg arg_ty)
            tyvar_kind = tyVarKind tyvar
            argty_kind = typeKind arg_ty
        in
-       if argty_kind `hasMoreBoxityInfo` tyvar_kind || -- Should the args be swapped here?
-          (isTypeKind argty_kind && isBoxedTypeKind tyvar_kind) -- (hackily) added SOF
+       if argty_kind `hasMoreBoxityInfo` tyvar_kind
                -- Arg type might be boxed for a function with an uncommitted
                -- tyvar; notably this is used so that we can give
                --      error :: forall a:*. String -> a
@@ -358,11 +358,9 @@ lintCoreAlts whole_alts@(PrimAlts alts deflt) ty --tycon
        where
          check ty = checkTys first_ty ty (mkCaseAltMsg whole_alts)
 
-lintAlgAlt scrut_ty {-tycon-ToDo: use it!-} (con,args,rhs)
+lintAlgAlt scrut_ty (con,args,rhs)
   = (case maybeAppDataTyConExpandingDicts scrut_ty of
-      Nothing ->
-        addErrL (mkAlgAltMsg1 scrut_ty)
-      Just (tycon, tys_applied, cons) ->
+      Just (tycon, tys_applied, cons) | isDataTyCon tycon ->
         let
           arg_tys = dataConArgTys con tys_applied
         in
@@ -371,6 +369,8 @@ lintAlgAlt scrut_ty {-tycon-ToDo: use it!-} (con,args,rhs)
                                                                 `seqL`
         mapL check (zipEqual "lintAlgAlt" arg_tys args)         `seqL`
         returnL ()
+
+      other -> addErrL (mkAlgAltMsg1 scrut_ty)
     )                                                           `seqL`
     addInScopeVars args        (
         lintCoreExpr rhs
@@ -396,6 +396,21 @@ lintDeflt deflt@(BindDefault binder rhs) ty
 
 %************************************************************************
 %*                                                                     *
+\subsection[lint-coercion]{Coercion}
+%*                                                                     *
+%************************************************************************
+
+\begin{code}
+lintCoercion e (CoerceIn  con) = check_con e con
+lintCoercion e (CoerceOut con) = check_con e con
+
+check_con e con = checkL (isNewCon con)
+                        (mkCoerceErrMsg e)
+\end{code}
+
+
+%************************************************************************
+%*                                                                     *
 \subsection[lint-monad]{The Lint monad}
 %*                                                                     *
 %************************************************************************
@@ -555,6 +570,15 @@ checkTys ty1 ty2 msg spec loc scope errs
 \end{code}
 
 \begin{code}
+mkConErrMsg e sty
+  = ($$) (ptext SLIT("Application of newtype constructor:"))
+           (ppr sty e)
+
+mkCoerceErrMsg e sty
+  = ($$) (ptext SLIT("Coercion using a datatype constructor:"))
+        (ppr sty e)
+
+
 mkCaseAltMsg :: CoreCaseAlts -> ErrMsg
 mkCaseAltMsg alts sty
   = ($$) (ptext SLIT("Type of case alternatives not the same:"))