Remove Gen.eval.

Fixes #268.

src/FsCheck/Gen.fs

@@ -155,20 +155,15 @@ module Gen =
     [<CompiledName("Resize")>]
     let resize newSize (Gen m) = Gen (fun _ r -> m newSize r)
 
-    ///Generates a value of the give size with the given seed.
-    //[category: Generating test values]
-    [<CompiledName("Eval")>]
-    let eval n rnd (Gen m) = 
-        let size,rnd' = Random.rangeInt (0, n, rnd)
-        (m size rnd').Value
-
     ///Generates n values of the given size.
     //[category: Generating test values]
     [<CompiledName("Sample")>]
-    let sample size n generator  = 
+    let sample size n (Gen generator)  = 
         let rec sample i seed samples =
             if i = 0 then samples
-            else sample (i-1) (Random.split seed |> snd) (eval size seed generator :: samples)
+            else
+                let sv = generator size seed
+                sample (i-1) sv.UpdatedState (sv.Value :: samples)
         sample n (Random.create()) []
 
     ///Generates an integer between l and h, inclusive.

src/FsCheck/GenExtensions.fs

@@ -8,12 +8,6 @@ open System.Collections.Generic
 [<AbstractClass; Sealed; System.Runtime.CompilerServices.Extension>]
 type GenExtensions = 
 
-    ///Generates a value with maximum size n.
-    //[category: Generating test values]
-    [<System.Runtime.CompilerServices.Extension>]
-    static member Eval(generator, size, random) =
-        eval size random generator
-
     ///Generates n values of the given size.
     //[category: Generating test values]
     [<System.Runtime.CompilerServices.Extension>]

src/FsCheck/Runner.fs

@@ -91,14 +91,17 @@ module Runner =
                 yield EndShrink result
         }
 
-    let rec private test initSize resize rnd0 gen =
-        seq { let rnd1,rnd2 = Random.split rnd0
+    let rec private test initSize resize rnd0 ((Gen eval) as gen) =
+        seq { // would like to get rid of this split,
+              // but the problem is DiscardException. If it is thrown,
+              // we also don't get the the updated Rnd back from eval.
+              let rnd1,rnd2 = Random.split rnd0
               let newSize = resize initSize
               //printfn "Before generate"
               //result forced here!
               let result, shrinks =
                   try
-                    let (MkRose (Lazy result,shrinks)) = Gen.eval (newSize |> round |> int) rnd2 gen
+                    let (MkRose (Lazy result,shrinks)) = (eval (newSize |> round |> int) rnd2).Value
                     result, shrinks
                     //printfn "After generate"
                     //problem: since result.Ok is no longer lazy, we only get the generated args _after_ the test is run

tests/FsCheck.Test/Runner.fs

@@ -137,12 +137,12 @@ module Runner =
         [<Property>]
         let ``should use configuration from enclosing module``(x:int) =
             // checking if the generated value is always the same (-59) from "01234,56789" Replay
-            x =! -84
+            x =! -4
 
         [<Property( Replay = "12345,67891")>]
         let ``should use configuration on method preferentially``(x:int) =
             // checking if the generated value is always the same (18) from "12345,67890" Replay
-            x =! 9
+            x =! -93
 
 module BugReproIssue195 =