There is no way to resolve the issue in the way you provided. But it could be done by defining the someMethod method as static:
list.forEach(item -> SomeClass.someMethod(item));
list.forEach(SomeClass::someMethod);
The statement SomeClass::new::someMethod is incorrect.
Strictly speaking, SomeClass::new refers to a piece of constructor code (like a Consumer), it does not return a new instance while you need an object to make a method reference SomeClassinstance::someMethod.
EDIT:
I really don't see any advantages of the approach:
map(SomeClass::new).forEach(SomeClass::someMethod)
because it leads to creation a portion of useless SomeClass instances with items that also will not be used.
::does not work with "pipelining".list.forEach(SomeClass::new)for calling thesomeMethod?itemagain in thesomeMethodcall? If that's not necessary, you could do something likelist.stream().map(SomeClass::new).forEach(SomeClass::someMethod).