dataflow to/from containers support

java/java-tests/testData/codeInsight/slice/backward/CollectionTrack.java

@@ -0,0 +1,37 @@
+package x;
+import java.util.*;
+import org.intellij.lang.annotations.Flow;
+
+public class ListTack {
+    void f(String <caret>s) {
+    }
+    void g(List<String> l) {
+        l.add(1, "uuu");
+
+        f(l.get(0));
+    }
+    void h() {
+        ArrayList<String> strings = new ArrayList<String>();
+        strings.add("x");
+        X<String> s2 = new X<String>(strings);
+        s2.add("y");
+        List<String> s3 = new ArrayList<String>();
+        s3.addAll(s2.toCollection());
+
+        Collection<String> s4 = new ArrayList<String>(s3.subList(0,1));
+        g(new ArrayList<String>(s4));
+    }
+
+  class X<T> {
+    X (@Flow(sourceIsContainer = true, targetIsContainer = true) Collection<T> input) {}
+
+    @Flow(sourceIsContainer = true)
+    T get() { return null;}
+
+    void add(@Flow(targetIsContainer = true) T item) {}
+
+    @Flow(sourceIsContainer=true, targetIsContainer = true)
+    Collection<T> toCollection() { return null; }
+  }
+}
+