[VFX] Fix Custom HLSL failure with in

Issue introduced at https://github.cds.internal.unity3d.com/unity/unity/commit/eb7e959a3fb7cae4dec459e2e5f5e7bd6ce28dd3 by this PR https://github.cds.internal.unity3d.com/unity/unity/pull/43339

Block is now consistent with Operator behavior https://github.cds.internal.unity3d.com/unity/unity/blob/8008bc0c1b747e1a435ebfe0b5685e80eb649be5/Packages/com.unity.visualeffectgraph/Editor/Models/Operators/Implementations/CustomHLSL.cs#L405

Author: PaulDemeulenaere

Packages/com.unity.visualeffectgraph/Editor/Models/Blocks/Implementations/HLSL/CustomHLSL.cs

@@ -324,7 +324,7 @@ private void ParseCodeIfNeeded()
                     m_Properties = new List<VFXPropertyWithValue>();
                     foreach (var input in m_Function.inputs)
                     {
-                        if (input.type != null && input.type != typeof(VFXAttribute) && input.access is HLSLAccess.IN)
+                        if (input.type != null && input.type != typeof(VFXAttribute) && input.access is HLSLAccess.IN or HLSLAccess.NONE)
                         {
                             m_Properties.Add(CreateProperty(input));
                         }

Tests/SRPTests/Projects/VisualEffectGraph_HDRP/Assets/AllTests/Editor/Tests/CustomHLSLBlockTest.cs

@@ -456,6 +456,34 @@ public IEnumerator Check_CustomHLSL_Block_VFXAttributes_Wrong_Access_Modifier()
             Assert.AreEqual("Missing `inout` access modifier before the VFXAttributes type.\nNeeded because your code writes to at least one attribute.", report.description);
         }
 
+        [UnityTest]
+        public IEnumerator Check_CustomHLSL_Block_VFXAttributes_Without_Access_Modifier()
+        {
+            // Arrange
+            var hlslCode =
+                "void TestFunction(inout VFXAttributes attributes, float param)\n" +
+                "{\n" +
+                "    attributes.position = float3(param, param, param);\n" +
+                "}";
+            var hlslBlock = ScriptableObject.CreateInstance<CustomHLSL>();
+            hlslBlock.SetSettingValue("m_HLSLCode", hlslCode);
+
+            MakeSimpleGraphWithCustomHLSL(hlslBlock, out var view, out var graph);
+            yield return null;
+
+            // Act
+            graph.errorManager.GenerateErrors();
+
+            // Assert
+            var report = graph.errorManager.errorReporter.GetDirtyModelErrors(hlslBlock);
+            Assert.IsFalse(report.Any());
+
+            //Check input slot contents
+            Assert.AreEqual(1, hlslBlock.inputSlots.Count);
+            Assert.AreEqual("param", hlslBlock.inputSlots[0].name);
+            Assert.AreEqual(VFXValueType.Float, hlslBlock.inputSlots[0].valueType);
+        }
+
         [Test]
         public void Check_CustomHLSL_Block_Includes()
         {