import java.util.*; import java.util.stream.Collectors; import java.util.stream.Stream; class A { void m(final Stream<String> stream){ Set<String> ALLOWED_PROPS = unmodifiableSet <error descr="'unmodifiableSet(java.util.Set<? extends java.lang.String>)' in 'A' cannot be applied to '(java.util.HashSet<java.lang.String>)'">(stream.collect(Collectors.toCollection(HashSet::new)))</error>; } public static <T1> Set<T1> unmodifiableSet(Set<? extends T1> s) { return null; } }