InfixExpression groupRoot= findGroupRoot((InfixExpression) node);
InfixExpression groupRoot= findGroupRoot(node);
	public static IExpressionFragment createSubPartFragmentBySourceRange(InfixExpression node, SourceRange range, ICompilationUnit cu) throws JavaModelException {		Assert.isNotNull(node);		Assert.isNotNull(range);		Assert.isTrue(!range.covers(node));		Assert.isTrue(new SourceRange(node).covers(range));		if(!isAssociativeInfix(node))			return null;				InfixExpression groupRoot= findGroupRoot((InfixExpression) node);		Assert.isTrue(isAGroupRoot(groupRoot));				List groupMembers= GroupMemberFinder.findGroupMembersInOrderFor(groupRoot);		List subGroup= findSubGroupForSourceRange(groupMembers, range);		if(subGroup.isEmpty() || rangeIncludesExtraNonWhitespace(range, subGroup, cu))			return null;				return new AssociativeInfixExpressionFragment(groupRoot, subGroup);	}