Nested Pseudo-classes
doc = Oga.parse_html '<div>a</div><div>b</div>'
doc.css('div:not(:nth-child(2))')
fails with:
C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/ruby-ll-2.1.2/lib/ll/driver.rb:15:in `parser_error': Unexpected T_NTH, expected T_IDENT instead (LL::ParserError)
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/parser.rb:270:in `block in each_token'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/lexer.rb:1011:in `add_token'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/lexer.rb:487:in `advance'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/parser.rb:269:in `each_token'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/parser.rb:293:in `parse'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/parser.rb:293:in `parse'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/parser.rb:245:in `block in parse_with_cache'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/lru.rb:79:in `block in get_or_set'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/lru.rb:122:in `synchronize'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/lru.rb:79:in `get_or_set'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/css/parser.rb:245:in `parse_with_cache'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/oga-2.11/lib/oga/xml/querying.rb:78:in `css'
from test.rb:4:in `<main>'
while this is a valid css3 selector (example).