[project @ 2004-11-09 17:38:01 by simonpj]

Remember to zonk the quantified type variables of a for-all type before forming the type

diff --git a/ghc/compiler/typecheck/TcRnDriver.lhs b/ghc/compiler/typecheck/TcRnDriver.lhs
index 02b586a..676792b 100644 (file)
--- a/ghc/compiler/typecheck/TcRnDriver.lhs
+++ b/ghc/compiler/typecheck/TcRnDriver.lhs
@@ -84,7 +84,7 @@ import TcHsSyn                ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
 import TcHsType                ( kcHsType )
 import TcExpr          ( tcCheckRho )
 import TcIface         ( loadImportedInsts )
-import TcMType         ( zonkTcType )
+import TcMType         ( zonkTcType, zonkQuantifiedTyVar )
 import TcUnify         ( unifyTyConApp )
 import TcMatches       ( tcStmtsAndThen, TcStmtCtxt(..) )
 import TcSimplify      ( tcSimplifyInteractive, tcSimplifyInfer )
@@ -903,8 +903,9 @@ tcRnExpr hsc_env ictxt rdr_expr
     ((tc_expr, res_ty), lie)      <- getLIE (tcInferRho rn_expr) ;
     ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie)  ;
     tcSimplifyInteractive lie_top ;
+    qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
 
-    let { all_expr_ty = mkForAllTys qtvs               $
+    let { all_expr_ty = mkForAllTys qtvs' $
                        mkFunTys (map idType dict_ids)  $
                        res_ty } ;
     zonkTcType all_expr_ty