C#: Add some model generator examples for higher order methods.

Author: michaelnebel

csharp/ql/test/utils/modelgenerator/dataflow/Summaries.cs

@@ -497,18 +497,55 @@ public Type M6(Type t)
     }
 }
 
-// No models as higher order methods are excluded
-// from model generation.
+// Methods in this class are "neutral" with respect to the heuristic model generation, but
+// the content based model generation is able to produce flow summaries for them.
 public class HigherOrderParameters
 {
+    // neutral=Models;HigherOrderParameters;M1;(System.String,System.Func<System.String,System.String>);summary;df-generated
+    // contentbased-summary=Models;HigherOrderParameters;false;M1;(System.String,System.Func<System.String,System.String>);;Argument[0];ReturnValue;value;dfc-generated
     public string M1(string s, Func<string, string> map)
     {
         return s;
     }
 
-    public object M2(Func<object, object> map, object o)
+    // neutral=Models;HigherOrderParameters;Map;(System.Func<System.Object,System.Object>,System.Object);summary;df-generated
+    // contentbased-summary=Models;HigherOrderParameters;false;Map;(System.Func<System.Object,System.Object>,System.Object);;Argument[1];Argument[0].Parameter[0];value;dfc-generated
+    // contentbased-summary=Models;HigherOrderParameters;false;Map;(System.Func<System.Object,System.Object>,System.Object);;Argument[0].ReturnValue;ReturnValue;value;dfc-generated
+    public object Map(Func<object, object> f, object o)
     {
-        return map(o);
+        return f(o);
+    }
+
+    // neutral=Models;HigherOrderParameters;Map2;(System.Object,System.Func<System.Object,System.Object,System.Object>);summary;df-generated
+    // contentbased-summary=Models;HigherOrderParameters;false;Map2;(System.Object,System.Func<System.Object,System.Object,System.Object>);;Argument[0];Argument[1].Parameter[1];value;dfc-generated
+    // contentbased-summary=Models;HigherOrderParameters;false;Map2;(System.Object,System.Func<System.Object,System.Object,System.Object>);;Argument[1].ReturnValue;ReturnValue;value;dfc-generated
+    public object Map2(object o, Func<object, object, object> f)
+    {
+        var x = f(null, o);
+        return x;
+    }
+
+    // neutral=Models;HigherOrderParameters;Apply;(System.Action<System.Object>,System.Object);summary;df-generated
+    // contentbased-summary=Models;HigherOrderParameters;false;Apply;(System.Action<System.Object>,System.Object);;Argument[1];Argument[0].Parameter[0];value;dfc-generated
+    public void Apply(Action<object> a, object o)
+    {
+        a(o);
+    }
+}
+
+public static class HigherOrderExtensionMethods
+{
+    // neutral=Models;HigherOrderExtensionMethods;Select<TSource,TResult>;(System.Collections.Generic.IEnumerable<TSource>,System.Func<TSource,TResult>);summary;df-generated
+    // contentbased-summary=Models;HigherOrderExtensionMethods;false;Select<TSource,TResult>;(System.Collections.Generic.IEnumerable<TSource>,System.Func<TSource,TResult>);;Argument[0].Element;Argument[1].Parameter[0];value;dfc-generated
+    // contentbased-summary=Models;HigherOrderExtensionMethods;false;Select<TSource,TResult>;(System.Collections.Generic.IEnumerable<TSource>,System.Func<TSource,TResult>);;Argument[1].ReturnValue;ReturnValue.Element;value;dfc-generated
+    public static IEnumerable<TResult> Select<TSource, TResult>(
+            this IEnumerable<TSource> source,
+            Func<TSource, TResult> selector)
+    {
+        foreach (var item in source)
+        {
+            yield return selector(item);
+        }
     }
 }