[notes]
This is a regression test for "Support direct calls to left-recursive
rules".  https://github.com/antlr/antlr4/issues/161

[type]
Parser

[grammar]
grammar T;
a @after {<ToStringTree("$ctx"):writeln()>} : a ID
  | ID
  ;
ID : 'a'..'z'+ ;
WS : (' '|'\n') -> skip ;

[start]
a

[input]
x

[output]
"""(a x)
"""