Merge pull request #392 from Micha-kun/master

Add Option.ofUnchecked function

src/FSharpx.Extras/ComputationExpressions/Option.fs

@@ -132,6 +132,12 @@ module Option =
         | Ok a -> Some a
         | _ -> None
 
+    /// Maps Unchecked object when null to None, otherwise Some value.
+    /// It's useful when getting data from external sources, pe.
+    let inline ofUnchecked (x: 'a when 'a : not struct) =
+        match box x with
+        | null -> None
+        | _ -> Some x
 
     /// Gets the value associated with the option or the supplied default value.
     let inline getOrElse v =

tests/FSharpx.Tests/OptionTests.fs

@@ -94,3 +94,22 @@ let someIfBoolTestCases = [
 [<TestCaseSource(nameof someIfBoolTestCases)>]
 let ``someIf with id`` (input:bool, expectedOutput:bool option) =
     Option.someIf id input |> shouldEqual expectedOutput
+
+type UncheckedRecordTest =
+    { Dummy: int }
+
+[<Test>]
+let ``from unchecked value``() =
+    let test = { Dummy = 4 }
+    Assert.AreEqual(Some test, Option.ofUnchecked test)
+    Assert.AreEqual(None, Option.ofUnchecked (Unchecked.defaultof<UncheckedRecordTest>))
+
+[<NoEquality;NoComparison>] 
+type UncheckedRecordTest2 =
+    { Dummy2: int }
+
+[<Test>]
+let ``from unchecked value without equality nor comparison``() =
+    let test = { Dummy2 = 4 }
+    Assert.AreEqual(Some test, Option.ofUnchecked test)
+    Assert.AreEqual(None, Option.ofUnchecked (Unchecked.defaultof<UncheckedRecordTest2>))