Add test for virtual-dispatch flow through binding patterns

java/ql/test/library-tests/dataflow/collections/options

@@ -0,0 +1 @@
+//semmle-extractor-options: --javac-args --release 21

java/ql/test/library-tests/virtual-dispatch-binding-patterns/Test.java

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+public class Test {
+
+  private interface Intf { String get(); }
+  private static class Specific implements Intf { public String get() { return "Specific"; } }
+  private static class Alternative implements Intf { public String get() { return "Alternative"; } }
+
+  public static String caller() {
+
+    Alternative a = new Alternative(); // Instantiate this somewhere so there are at least two candidate types in general
+    return test(new Specific());
+
+  }
+
+  public static String test(Object o) {
+
+    if (o instanceof Intf i) {
+      // So we should know i.get is really Specific.get():
+      return i.get();
+    }
+
+    switch (o) {
+      case Intf i -> { return i.get(); } // Same goes for this `i`
+      default -> { return "Not an Intf"; }
+    }
+
+  }
+
+}
+

java/ql/test/library-tests/virtual-dispatch-binding-patterns/options

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+//semmle-extractor-options: --javac-args --release 21

java/ql/test/library-tests/virtual-dispatch-binding-patterns/test.expected

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+| Test.java:1:14:1:17 | super(...) | java.lang.Object.Object |
+| Test.java:4:24:4:31 | super(...) | java.lang.Object.Object |
+| Test.java:5:24:5:34 | super(...) | java.lang.Object.Object |
+| Test.java:9:21:9:37 | new Alternative(...) | Test$Alternative.Alternative |
+| Test.java:10:12:10:31 | test(...) | Test.test |
+| Test.java:10:17:10:30 | new Specific(...) | Test$Specific.Specific |
+| Test.java:18:14:18:20 | get(...) | Test$Specific.get |
+| Test.java:22:31:22:37 | get(...) | Test$Specific.get |

java/ql/test/library-tests/virtual-dispatch-binding-patterns/test.ql

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+import java
+
+import semmle.code.java.dispatch.VirtualDispatch
+
+from Call c, Callable c2
+where c2 = viableCallable(c)
+select c, c2.getQualifiedName()