Add tests for Java 21 unnamed patterns

TODO: Activate after
https://github.com/eclipse-jdt/eclipse.jdt.core/issues/893 is done.
Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

1 files changed, 89 insertions, 0 deletions

diff --git a/tests/features1921/java21/UnnamedPatternsPreview1Aspect.aj b/tests/features1921/java21/UnnamedPatternsPreview1Aspect.aj
new file mode 100644
index 000000000..d224a94fc
--- /dev/null
+++ b/tests/features1921/java21/UnnamedPatternsPreview1Aspect.aj
@@ -0,0 +1,89 @@
+import java.awt.*;
+import java.util.List;
+import java.util.PriorityQueue;
+import java.util.Queue;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * Examples taken from <a href="https://openjdk.org/jeps/443">JEP 443</a>
+ */
+public class UnnamedPatternsPreview1Aspect {
+  public static void main(String[] args) {}
+
+  before() : execution(* main(String[])) {
+    System.out.println(thisJoinPoint);
+
+    // An enhanced for loop with side effects
+    int acc = 0;
+    final int LIMIT = 2;
+    for (Order _ : List.of(new Order(), new Order(), new Order())) {
+      if (acc < LIMIT)
+        acc++;
+    }
+    System.out.println(acc);
+
+    // The initialisation of a basic for loop can declare unnamed local variables
+    for (int i = 0, _ = sideEffect(); i < 2; i++) {
+      System.out.println(i);
+    }
+
+    // An assignment statement, where the result of the expression on the right hand side is not needed
+    Queue<Integer> q = new PriorityQueue<>(List.of(1, 2, 3, 4, 5, 6));
+    while (q.size() >= 3) {
+      var x = q.remove();
+      var y = q.remove();
+      var _ = q.remove();
+      System.out.println(new Point(x, y));
+    }
+
+    // The same unnamed variable name '_' can be used in multiple assignment statements
+    q = new PriorityQueue<>(List.of(1, 2, 3, 4, 5, 6));
+    while (q.size() >= 3) {
+      var x = q.remove();
+      var _ = q.remove();
+      var _ = q.remove();
+      System.out.println(new Point(x, 0));
+    }
+
+    // Unnamed variables can be used in one or multiple catch blocks
+    String s = "123xy";
+    try {
+      int i = Integer.parseInt(s);
+      System.out.println(i);
+    } catch (NumberFormatException _) {
+      System.out.println("Bad number: " + s);
+    } catch (Exception _) {
+      System.out.println("Unexpected error");
+    }
+
+    // Try with resources
+    try (var _ = ScopedContext.acquire()) {
+      System.out.println("Doing something within scoped context");
+    }
+
+    // A lambda whose parameter is irrelevant
+    System.out.println(
+      Stream.of("one", "two", "three")
+        .collect(Collectors.toMap(String::toUpperCase, _ -> "NODATA"))
+    );
+  }
+
+  static int sideEffect() {
+    System.out.println("side effect");
+    return 42;
+  }
+
+  static class Order {}
+
+  static class ScopedContext implements AutoCloseable {
+    public static ScopedContext acquire() {
+      return new ScopedContext();
+    }
+
+    @Override
+    public void close() {
+      System.out.println("Closing scoped context");
+    }
+  }
+}