$ javac --enable-preview --release 26 broken/MissingCatch.java     (26.0.2.1+1)
exit=0

$ javac broken/MissingCatch.java     (28-beta+21-ea)
broken/MissingCatch.java:8: error: unreported exception ExecutionException; must be caught or declared to be thrown
            scope.join();
                      ^
1 error
exit=1

$ javac --enable-preview --release 26 broken/OldFailedException.java     (26.0.2.1+1)
exit=0

$ javac broken/OldFailedException.java     (28-beta+21-ea)
broken/OldFailedException.java:9: error: cannot find symbol
        } catch (StructuredTaskScope.FailedException e) {
                                    ^
  symbol:   class FailedException
  location: interface StructuredTaskScope
1 error
exit=1

$ javac --enable-preview --release 26 broken/OldTimeoutException.java     (26.0.2.1+1)
exit=0

$ javac broken/OldTimeoutException.java     (28-beta+21-ea)
broken/OldTimeoutException.java:11: error: cannot find symbol
        } catch (StructuredTaskScope.TimeoutException e) {
                                    ^
  symbol:   class TimeoutException
  location: interface StructuredTaskScope
1 error
exit=1

$ javac --enable-preview --release 26 broken/AwaitAll.java     (26.0.2.1+1)
exit=0

$ javac broken/AwaitAll.java     (28-beta+21-ea)
broken/AwaitAll.java:7: error: cannot find symbol
        try (var scope = StructuredTaskScope.open(Joiner.<String>awaitAll())) {
                                                        ^
  symbol:   method <String>awaitAll()
  location: interface Joiner
1 error
exit=1

$ javac --enable-preview --release 26 broken/OldJoiner.java     (26.0.2.1+1)
exit=0

$ javac broken/OldJoiner.java     (28-beta+21-ea)
broken/OldJoiner.java:7: error: wrong number of type arguments; required 3
public class OldJoiner<T> implements Joiner<T, List<T>> {
                                           ^
1 error
exit=1

$ javac --enable-preview --release 26 broken/ShutdownOnFailure.java     (26.0.2.1+1)
broken/ShutdownOnFailure.java:6: error: cannot find symbol
        try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
                                                ^
  symbol:   class ShutdownOnFailure
  location: interface StructuredTaskScope
1 error
exit=1

$ javac broken/ShutdownOnFailure.java     (28-beta+21-ea)
broken/ShutdownOnFailure.java:6: error: cannot find symbol
        try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
                                                ^
  symbol:   class ShutdownOnFailure
  location: interface StructuredTaskScope
1 error
exit=1

# the same sources on JDK 25 for ShutdownOnFailure
$ javac --enable-preview --release 25 broken/ShutdownOnFailure.java     (25.0.5+8-LTS)
broken/ShutdownOnFailure.java:6: error: cannot find symbol
        try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
                                                ^
  symbol:   class ShutdownOnFailure
  location: interface StructuredTaskScope
1 error
exit=1