import java.util.List;
import java.util.stream.Collector;
public class CrashRepro {
static <E> Collector<E, ?, List<E>> toList() {
throw new UnsupportedOperationException();
}
Object convert(Object value) {
if (value instanceof List) {
return ((List) value).stream().map(item -> convert(item)).collect(toList());
}
return value;
}
}$ ./checker-framework-4.0.0/checker/bin/javac -processor nullness CrashRepro.java |& head -n 30
CrashRepro.java:11: error: [return] incompatible types in return.
return ((List) value).stream().map(item -> convert(item)).collect(toList());
^
type of expression: @Initialized @Nullable Object
method return type: @Initialized @NonNull Object
CrashRepro.java:11: error: [type.arguments.not.inferred] Could not infer type arguments for Stream.collect
return ((List) value).stream().map(item -> convert(item)).collect(toList());
^
unsatisfiable constraint: @Initialized @Nullable Object -> @Initialized @NonNull Object
From: Constraint between method call type and target type for method call:((List)value).stream().map((item)->convert(item)).collect(toList())
CrashRepro.java:11: error: [type.argument.inference.crashed] Type argument inference crashed for CrashRepro.toList
return ((List) value).stream().map(item -> convert(item)).collect(toList());
^
error: An exception occurred: Cannot invoke "java.util.Map.keySet()" because "map" is null
Note: CrashRepro.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
3 errors
