C#: Add data flow test that illustrates issue with flow into phi nodes

Author: hvitved

csharp/ql/test/library-tests/dataflow/fields/FieldFlow.expected

@@ -1,4 +1,6 @@
 failures
+| J.cs:125:21:125:40 | // ... | Missing result:hasValueFlow=10 |
+| J.cs:140:14:140:17 | (...) ... | Unexpected result: hasValueFlow=11 |
 edges
 | A.cs:5:17:5:28 | call to method Source<C> : C | A.cs:6:24:6:24 | access to local variable c : C |
 | A.cs:5:17:5:28 | call to method Source<C> : C | A.cs:6:24:6:24 | access to local variable c : C |
@@ -918,6 +920,14 @@ edges
 | J.cs:106:14:106:15 | access to local variable a3 [property X] : Object | J.cs:106:14:106:17 | access to property X |
 | J.cs:107:14:107:15 | access to local variable a3 [property Y] : Object | J.cs:107:14:107:17 | access to property Y |
 | J.cs:107:14:107:15 | access to local variable a3 [property Y] : Object | J.cs:107:14:107:17 | access to property Y |
+| J.cs:133:13:133:13 | [post] access to local variable a [element] : Int32 | J.cs:140:14:140:14 | access to local variable a [element] : Int32 |
+| J.cs:133:13:133:13 | [post] access to local variable a [element] : Int32 | J.cs:140:14:140:14 | access to local variable a [element] : Int32 |
+| J.cs:133:19:133:33 | call to method Source<Int32> : Int32 | J.cs:133:13:133:13 | [post] access to local variable a [element] : Int32 |
+| J.cs:133:19:133:33 | call to method Source<Int32> : Int32 | J.cs:133:13:133:13 | [post] access to local variable a [element] : Int32 |
+| J.cs:140:14:140:14 | access to local variable a [element] : Int32 | J.cs:140:14:140:17 | access to indexer : Int32 |
+| J.cs:140:14:140:14 | access to local variable a [element] : Int32 | J.cs:140:14:140:17 | access to indexer : Int32 |
+| J.cs:140:14:140:17 | access to indexer : Int32 | J.cs:140:14:140:17 | (...) ... |
+| J.cs:140:14:140:17 | access to indexer : Int32 | J.cs:140:14:140:17 | (...) ... |
 nodes
 | A.cs:5:17:5:28 | call to method Source<C> : C | semmle.label | call to method Source<C> : C |
 | A.cs:5:17:5:28 | call to method Source<C> : C | semmle.label | call to method Source<C> : C |
@@ -1925,6 +1935,16 @@ nodes
 | J.cs:107:14:107:15 | access to local variable a3 [property Y] : Object | semmle.label | access to local variable a3 [property Y] : Object |
 | J.cs:107:14:107:17 | access to property Y | semmle.label | access to property Y |
 | J.cs:107:14:107:17 | access to property Y | semmle.label | access to property Y |
+| J.cs:133:13:133:13 | [post] access to local variable a [element] : Int32 | semmle.label | [post] access to local variable a [element] : Int32 |
+| J.cs:133:13:133:13 | [post] access to local variable a [element] : Int32 | semmle.label | [post] access to local variable a [element] : Int32 |
+| J.cs:133:19:133:33 | call to method Source<Int32> : Int32 | semmle.label | call to method Source<Int32> : Int32 |
+| J.cs:133:19:133:33 | call to method Source<Int32> : Int32 | semmle.label | call to method Source<Int32> : Int32 |
+| J.cs:140:14:140:14 | access to local variable a [element] : Int32 | semmle.label | access to local variable a [element] : Int32 |
+| J.cs:140:14:140:14 | access to local variable a [element] : Int32 | semmle.label | access to local variable a [element] : Int32 |
+| J.cs:140:14:140:17 | (...) ... | semmle.label | (...) ... |
+| J.cs:140:14:140:17 | (...) ... | semmle.label | (...) ... |
+| J.cs:140:14:140:17 | access to indexer : Int32 | semmle.label | access to indexer : Int32 |
+| J.cs:140:14:140:17 | access to indexer : Int32 | semmle.label | access to indexer : Int32 |
 subpaths
 | A.cs:6:24:6:24 | access to local variable c : C | A.cs:147:32:147:32 | c : C | A.cs:149:20:149:27 | object creation of type B [field c] : C | A.cs:6:17:6:25 | call to method Make [field c] : C |
 | A.cs:6:24:6:24 | access to local variable c : C | A.cs:147:32:147:32 | c : C | A.cs:149:20:149:27 | object creation of type B [field c] : C | A.cs:6:17:6:25 | call to method Make [field c] : C |
@@ -2101,3 +2121,4 @@ subpaths
 | J.cs:102:14:102:17 | access to property X | J.cs:97:17:97:33 | call to method Source<Object> : Object | J.cs:102:14:102:17 | access to property X | $@ | J.cs:97:17:97:33 | call to method Source<Object> : Object | call to method Source<Object> : Object |
 | J.cs:106:14:106:17 | access to property X | J.cs:97:17:97:33 | call to method Source<Object> : Object | J.cs:106:14:106:17 | access to property X | $@ | J.cs:97:17:97:33 | call to method Source<Object> : Object | call to method Source<Object> : Object |
 | J.cs:107:14:107:17 | access to property Y | J.cs:105:32:105:48 | call to method Source<Object> : Object | J.cs:107:14:107:17 | access to property Y | $@ | J.cs:105:32:105:48 | call to method Source<Object> : Object | call to method Source<Object> : Object |
+| J.cs:140:14:140:17 | (...) ... | J.cs:133:19:133:33 | call to method Source<Int32> : Int32 | J.cs:140:14:140:17 | (...) ... | $@ | J.cs:133:19:133:33 | call to method Source<Int32> : Int32 | call to method Source<Int32> : Int32 |

csharp/ql/test/library-tests/dataflow/fields/J.cs

@@ -111,6 +111,35 @@ private void M5()
         Sink(a4.Y); // no flow
     }
 
+    private void M6(bool b)
+    {
+        var a = new int[1];
+        if (b)
+        {
+            a[0] = Source<int>(10);
+        }
+        else
+        {
+            a = new int[1];
+        }
+        Sink(a[0]); // $ hasValueFlow=10
+    }
+
+    private void M7(bool b)
+    {
+        var a = new System.Collections.Generic.List<int>();
+        if (b)
+        {
+            a.Add(Source<int>(11));
+            a.Clear();
+        }
+        else
+        {
+            a = new System.Collections.Generic.List<int>();
+        }
+        Sink(a[0]);
+    }
+
     public static void Sink(object o) { }
 
     static T Source<T>(object source) => throw null;