C#: Test cases for IEnumerable.

Author: michaelnebel

csharp/ql/test/utils/model-generator/CaptureSummaryModels.expected

@@ -13,3 +13,6 @@
 | Summaries;CollectionFlow;false;ReturnArrayElement;(System.Int32[]);Argument[0].Element;ReturnValue;taint |
 | Summaries;CollectionFlow;false;ReturnFieldInAList;();Argument[Qualifier];ReturnValue;taint |
 | Summaries;CollectionFlow;false;ReturnListElement;(System.Collections.Generic.List<System.Object>);Argument[0].Element;ReturnValue;taint |
+| Summaries;IEnumerableFlow;false;ReturnFieldInIEnumerable;();Argument[Qualifier];ReturnValue;taint |
+| Summaries;IEnumerableFlow;false;ReturnIEnumerable;(System.Collections.Generic.IEnumerable<System.String>);Argument[0].Element;ReturnValue;taint |
+| Summaries;IEnumerableFlow;false;ReturnIEnumerableElement;(System.Collections.Generic.IEnumerable<System.Object>);Argument[0].Element;ReturnValue;taint |

csharp/ql/test/utils/model-generator/Summaries.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.Collections.Generic;
 
 namespace Summaries;
@@ -82,3 +83,23 @@ public List<string> ReturnFieldInAList()
         return new List<string> { tainted };
     }
 }
+
+public class IEnumerableFlow
+{
+    private string tainted;
+
+    public IEnumerable<string> ReturnIEnumerable(IEnumerable<string> input)
+    {
+        return input;
+    }
+
+    public object ReturnIEnumerableElement(IEnumerable<object> input)
+    {
+        return input.First();
+    }
+
+    public IEnumerable<string> ReturnFieldInIEnumerable()
+    {
+        return new List<string> { tainted };
+    }
+}

csharp/ql/test/utils/model-generator/options

@@ -0,0 +1 @@
+semmle-extractor-options: /r:System.Linq.dll