Added new EmptyArray function. (#379)

src/Simulation/QsharpCore/Arrays/Empty.cs

@@ -0,0 +1,19 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using Microsoft.Quantum.Simulation.Core;
+
+namespace Microsoft.Quantum.Arrays
+{
+    public partial class EmptyArray<__TElement__>
+    {
+        public class Native : EmptyArray<__TElement__>
+        {
+            public Native(IOperationFactory m) : base(m) { }
+            public override Func<QVoid, IQArray<__TElement__>> __Body__ => _ =>
+                new QArray<__TElement__>();
+        }
+    }
+
+}

src/Simulation/QsharpCore/Arrays/Empty.qs

@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace Microsoft.Quantum.Arrays {
+
+    /// # Summary
+    /// Returns the empty array of a given type.
+    ///
+    /// # Type Parameters
+    /// ## 'TElement
+    /// The type of elements of the array.
+    ///
+    /// # Output
+    /// The empty array.
+    ///
+    /// # Example
+    /// ```Q#
+    /// let empty = EmptyArray<Int>();
+    /// ```
+    function EmptyArray<'TElement>() : 'TElement[] {
+        body intrinsic;
+    }
+
+}

src/Simulation/Simulators.Tests/TestProjects/IntrinsicTests/Arrays/Tests.qs

@@ -0,0 +1,22 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace Microsoft.Quantum.Arrays {
+    open Microsoft.Quantum.Diagnostics;
+
+    /// # Summary
+    /// Checks that empty arrays are indeed empty.
+    @Test("QuantumSimulator")
+    @Test("ToffoliSimulator")
+    function EmptyArraysAreEmpty() : Unit {
+        Fact(
+            Length(EmptyArray<Int>()) == 0,
+            "Empty array of type Int[] was not actually empty."
+        );
+        Fact(
+            Length(EmptyArray<(Double, Pauli[])>()) == 0,
+            "Empty array of type (Double, Pauli[])[] was not actually empty."
+        );
+    }
+
+}

src/Simulation/Simulators.Tests/TestProjects/IntrinsicTests/Random/Tests.qs

@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 namespace Microsoft.Quantum.Tests {
     open Microsoft.Quantum.Intrinsic;
     open Microsoft.Quantum.Canon;