More hacking on monad-comp; now works

[ghc-hetmet.git] / compiler / typecheck / TcRnDriver.lhs

diff --git a/compiler/typecheck/TcRnDriver.lhs b/compiler/typecheck/TcRnDriver.lhs
index b9f7913..7b1d5a6 100644 (file)
--- a/compiler/typecheck/TcRnDriver.lhs
+++ b/compiler/typecheck/TcRnDriver.lhs
@@ -1269,11 +1269,25 @@ tcGhciStmts stmts
        let {
            ret_ty    = mkListTy unitTy ;
            io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
-           tc_io_stmts stmts = tcStmts GhciStmt tcDoStmt stmts io_ret_ty ;
-
+           tc_io_stmts stmts = tcStmtsAndThen GhciStmt tcDoStmt stmts io_ret_ty ;
            names = collectLStmtsBinders stmts ;
+        } ;
+
+       -- OK, we're ready to typecheck the stmts
+       traceTc "TcRnDriver.tcGhciStmts: tc stmts" empty ;
+       ((tc_stmts, ids), lie) <- captureConstraints $ 
+                                  tc_io_stmts stmts  $ \ _ ->
+                                 mapM tcLookupId names  ;
+                       -- Look up the names right in the middle,
+                       -- where they will all be in scope
 
-               -- mk_return builds the expression
+       -- Simplify the context
+       traceTc "TcRnDriver.tcGhciStmts: simplify ctxt" empty ;
+       const_binds <- checkNoErrs (simplifyInteractive lie) ;
+               -- checkNoErrs ensures that the plan fails if context redn fails
+
+       traceTc "TcRnDriver.tcGhciStmts: done" empty ;
+        let {   -- mk_return builds the expression
                --      returnIO @ [()] [coerce () x, ..,  coerce () z]
                --
                -- Despite the inconvenience of building the type applications etc,
@@ -1284,27 +1298,14 @@ tcGhciStmts stmts
                -- then the type checker would instantiate x..z, and we wouldn't
                -- get their *polymorphic* values.  (And we'd get ambiguity errs
                -- if they were overloaded, since they aren't applied to anything.)
-           mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty]) 
-                                   (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
+           ret_expr = nlHsApp (nlHsTyApp ret_id [ret_ty]) 
+                      (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
            mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
-                                (nlHsVar id) 
-        } ;
-
-       -- OK, we're ready to typecheck the stmts
-       traceTc "TcRnDriver.tcGhciStmts: tc stmts" empty ;
-       ((tc_stmts, ids), lie) <- captureConstraints $ tc_io_stmts stmts $ \ _ ->
-                                          mapM tcLookupId names ;
-                                       -- Look up the names right in the middle,
-                                       -- where they will all be in scope
-
-       -- Simplify the context
-       traceTc "TcRnDriver.tcGhciStmts: simplify ctxt" empty ;
-       const_binds <- checkNoErrs (simplifyInteractive lie) ;
-               -- checkNoErrs ensures that the plan fails if context redn fails
-
-       traceTc "TcRnDriver.tcGhciStmts: done" empty ;
+                                (nlHsVar id) ;
+           stmts = tc_stmts ++ [noLoc (mkLastStmt ret_expr)]
+        } ;
        return (ids, mkHsDictLet (EvBinds const_binds) $
-                    noLoc (HsDo GhciStmt tc_stmts (mk_return ids) noSyntaxExpr io_ret_ty))
+                    noLoc (HsDo GhciStmt stmts io_ret_ty))
     }
 \end{code}