[antlr-interest] Problem removing warning

[Gerald Rosenberg]

Having a bit of difficulty in figuring out how to unambiguously parse 
this into an AST.
Order of the elements is significant, the parens are significant, and 
the leading dot is significant.

   (.buf_unittest.complex_opt1).foo;
   .buf_unittest.complex_opt1.fum;
   (buf_unittest.complex_opt1).(.buf_unittest.quux);
   (.buf_unittest.complex_opt1).(buf_unittest.corge).qux;
   (complex_opt2).baz;
   (complex_opt2).(grault);
   (complex_opt2).bar.foo;
   (complex_opt2).bar.(quux);
   (complex_opt2).bar.(buf_unittest.corge).qux;
   (complex_opt2).(garply).foo;
   (complex_opt2).(garply).(.buf_unittest.quux);
   (complex_opt2).(buf_unittest.garply).(corge).qux;
   (ComplexOptionType2.ComplexOptionType4.complex_opt4).waldo;
   (complex_opt2).fred.waldo;
   (buf_unittest.complex_opt3).qux;
   (complex_opt3).complexoptiontype5.plugh;
   (complexopt6).xyzzy;

The rule ident_parens following appears to work, but Antlr is 
complaining "Decision can match input such as "'.' ID" using multiple 
alternatives: 1, 2" on both identN and identO.  I can see the 
theoretical overlap, but cannot tell if the warning is actually 
significant or how to fix the rules to avoid the warning.

ident_parens
     : (identM | identN | identO ) ('.' ( identM | identO ) )*
     ;

identM
     :  '(' '.' ipd+=ID ( '.' ipd+=ID )* ')'   -> ^( IDENT_PARENSDOT $ipd+ )
     |  '(' ip+=ID ( '.' ip+=ID )* ')'         -> ^( IDENT_PARENS $ip+ )
     ;

identN
     : '.' id+=ID ( '.' id+=ID )*              -> ^( IDENT_DOT $id+ )
     ;

identO
     : i+=ID ( '.' i+=ID )*                    -> ^( IDENT $i+ )
     ;


Thanks...

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