C#: Test example with ref local, unsafe context and ref struct in async and iterator methods.

csharp/ql/test/library-tests/async/Async.expected

@@ -12,3 +12,6 @@
 | async.cs:50:49:50:57 | OpenAsync | file://:0:0:0:0 | async |
 | async.cs:50:49:50:57 | OpenAsync | file://:0:0:0:0 | private |
 | async.cs:50:49:50:57 | OpenAsync | file://:0:0:0:0 | static |
+| async.cs:64:40:64:53 | GetObjectAsync | file://:0:0:0:0 | async |
+| async.cs:64:40:64:53 | GetObjectAsync | file://:0:0:0:0 | private |
+| async.cs:64:40:64:53 | GetObjectAsync | file://:0:0:0:0 | static |

csharp/ql/test/library-tests/async/Await.expected

@@ -3,3 +3,4 @@
 | 42 | async.cs:42:46:42:70 | await ... | async.cs:42:52:42:70 | call to method OpenAsync |
 | 44 | async.cs:44:38:44:66 | await ... | async.cs:44:44:44:66 | call to method ReadToEndAsync |
 | 52 | async.cs:52:13:52:51 | await ... | async.cs:52:19:52:51 | call to method PrintContentLengthAsync |
+| 73 | async.cs:73:13:73:31 | await ... | async.cs:73:19:73:31 | call to method Delay |

csharp/ql/test/library-tests/async/async.cs

@@ -52,5 +52,26 @@ namespace Semmle
             await PrintContentLengthAsync(filename);
             return File.OpenText(filename);
         }
+
+        private ref struct RS
+        {
+            public int GetZero() { return 0; }
+        }
+
+        private static int one = 1;
+
+        // Test that we can use ref locals, ref structs and unsafe blocks in async methods.
+        private static async Task<int> GetObjectAsync()
+        {
+            unsafe
+            {
+                // Do pointer stuff
+            }
+            RS rs;
+            ref int i = ref one;
+            var zero = rs.GetZero();
+            await Task.Delay(i);
+            return zero;
+        }
     }
 }

csharp/ql/test/library-tests/iterators/iterators.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+
+public ref struct RS
+{
+    public int GetZero() { return 0; }
+}
+
+public class C
+{
+    private int one = 1;
+
+    // Test that we can use unsafe context, ref locals and ref structs in iterators.
+    public IEnumerable<int> GetObjects()
+    {
+        unsafe
+        {
+            // Do pointer stuff
+        }
+        ref int i = ref one;
+        RS rs;
+        var zero = rs.GetZero();
+        yield return zero;
+    }
+}

csharp/ql/test/library-tests/iterators/iterators.expected

@@ -0,0 +1 @@
+| iterators.cs:14:29:14:38 | GetObjects | iterators.cs:23:22:23:25 | access to local variable zero |

csharp/ql/test/library-tests/iterators/iterators.ql

@@ -0,0 +1,5 @@
+import csharp
+
+from Callable c, Expr return
+where c.canYieldReturn(return)
+select c, return