C#: Add test and expected output.

Author: michaelnebel

csharp/ql/test/library-tests/collections/CollectionExpressions.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Linq;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel;
+
+public class MyClass
+{
+    public void M1()
+    {
+        var y = 4;
+        int[] x1 = [1 + 4, 2, 8];
+        Span<int> x2 = [3, y];
+        int[] all = [.. x1, .. x2];
+        int[][] jagged = [[1, y], x1];
+        int[] nested = [1, .. (int[])[.. x1]];
+        IntegerCollection collection = [4, y, 9, .. x1];
+        M2([1, 2, 3]);
+    }
+
+    public static void M2(Span<int> x) { }
+
+    public static void M2(ReadOnlySpan<int> x) { }
+}
+
+[System.Runtime.CompilerServices.CollectionBuilder(typeof(IntegerCollectionBuilder), "Create")]
+public class IntegerCollection : IEnumerable<int>
+{
+    private int[] items;
+
+    public IntegerCollection(ReadOnlySpan<int> items)
+    {
+        this.items = items.ToArray();
+    }
+
+    public IEnumerator<int> GetEnumerator() => items.AsEnumerable<int>().GetEnumerator();
+
+    IEnumerator IEnumerable.GetEnumerator() => items.GetEnumerator();
+}
+
+public static class IntegerCollectionBuilder
+{
+    public static IntegerCollection Create(ReadOnlySpan<int> elements)
+        => new IntegerCollection(elements);
+}
+

csharp/ql/test/library-tests/collections/collectionExpressions.expected

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+| CollectionExpressions.cs:12:20:12:32 | [...] | Int32[] | 0 | CollectionExpressions.cs:12:21:12:25 | ... + ... |
+| CollectionExpressions.cs:12:20:12:32 | [...] | Int32[] | 1 | CollectionExpressions.cs:12:28:12:28 | 2 |
+| CollectionExpressions.cs:12:20:12:32 | [...] | Int32[] | 2 | CollectionExpressions.cs:12:31:12:31 | 8 |
+| CollectionExpressions.cs:13:24:13:29 | [...] | Span<Int32> | 0 | CollectionExpressions.cs:13:25:13:25 | 3 |
+| CollectionExpressions.cs:13:24:13:29 | [...] | Span<Int32> | 1 | CollectionExpressions.cs:13:28:13:28 | access to local variable y |
+| CollectionExpressions.cs:14:21:14:34 | [...] | Int32[] | 0 | CollectionExpressions.cs:14:22:14:26 | .. access to local variable x1 |
+| CollectionExpressions.cs:14:21:14:34 | [...] | Int32[] | 1 | CollectionExpressions.cs:14:29:14:33 | .. access to local variable x2 |
+| CollectionExpressions.cs:15:26:15:37 | [...] | Int32[][] | 0 | CollectionExpressions.cs:15:27:15:32 | [...] |
+| CollectionExpressions.cs:15:26:15:37 | [...] | Int32[][] | 1 | CollectionExpressions.cs:15:35:15:36 | access to local variable x1 |
+| CollectionExpressions.cs:15:27:15:32 | [...] | Int32[] | 0 | CollectionExpressions.cs:15:28:15:28 | 1 |
+| CollectionExpressions.cs:15:27:15:32 | [...] | Int32[] | 1 | CollectionExpressions.cs:15:31:15:31 | access to local variable y |
+| CollectionExpressions.cs:16:24:16:45 | [...] | Int32[] | 0 | CollectionExpressions.cs:16:25:16:25 | 1 |
+| CollectionExpressions.cs:16:24:16:45 | [...] | Int32[] | 1 | CollectionExpressions.cs:16:28:16:44 | .. (...) ... |
+| CollectionExpressions.cs:16:38:16:44 | [...] | Int32[] | 0 | CollectionExpressions.cs:16:39:16:43 | .. access to local variable x1 |
+| CollectionExpressions.cs:17:40:17:55 | [...] | IntegerCollection | 0 | CollectionExpressions.cs:17:41:17:41 | 4 |
+| CollectionExpressions.cs:17:40:17:55 | [...] | IntegerCollection | 1 | CollectionExpressions.cs:17:44:17:44 | access to local variable y |
+| CollectionExpressions.cs:17:40:17:55 | [...] | IntegerCollection | 2 | CollectionExpressions.cs:17:47:17:47 | 9 |
+| CollectionExpressions.cs:17:40:17:55 | [...] | IntegerCollection | 3 | CollectionExpressions.cs:17:50:17:54 | .. access to local variable x1 |
+| CollectionExpressions.cs:18:12:18:20 | [...] | ReadOnlySpan<Int32> | 0 | CollectionExpressions.cs:18:13:18:13 | 1 |
+| CollectionExpressions.cs:18:12:18:20 | [...] | ReadOnlySpan<Int32> | 1 | CollectionExpressions.cs:18:16:18:16 | 2 |
+| CollectionExpressions.cs:18:12:18:20 | [...] | ReadOnlySpan<Int32> | 2 | CollectionExpressions.cs:18:19:18:19 | 3 |

csharp/ql/test/library-tests/collections/collectionExpressions.ql

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+import csharp
+
+from CollectionExpression ce, Expr element, int i
+where element = ce.getElement(i)
+select ce, ce.getType().toString(), i.toString(), element

csharp/ql/test/library-tests/collections/options

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+semmle-extractor-options: /nostdlib /noconfig
+semmle-extractor-options: --load-sources-from-project:${testdir}/../../resources/stubs/_frameworks/Microsoft.NETCore.App/Microsoft.NETCore.App.csproj