ANTLR backend: malformed lexer file when using subtraction in regular expression

[andreasabel]

Start. S ::= Name ;
token Name (char - [ "(){};.@\" \n\t" ]) + ;

This yields a ANTLR lexer file containing:

// This Antlr4 file was machine-generated by the BNF converter
lexer grammar testLexer;
// Predefined regular expressions in BNFC
fragment LETTER  : CAPITAL | SMALL ;
fragment CAPITAL : [A-Z\u00C0-\u00D6\u00D8-\u00DE] ;
fragment SMALL   : [a-z\u00DF-\u00F6\u00F8-\u00FF] ;
fragment DIGIT   : [0-9] ;


Name : ~[
 "().;@{}]+;





// Whitespace
WS : (' ' | '\r' | '\t' | '\n' | '\f')+ ->  skip;
// Escapable sequences
fragment
Escapable : ('"' | '\\' | 'n' | 't' | 'r' | 'f');
ErrorToken : . ;

This raises the following errors:

java  org.antlr.v4.Tool -lib test -package test test/testLexer.g4
error(50): testLexer.g4:10:8: syntax error: '[' came as a complete surprise to me
error(50): testLexer.g4:11:1: syntax error: '"' came as a complete surprise to me
error(50): testLexer.g4:11:3: syntax error: ')' came as a complete surprise to me while looking for lexer rule element
error(50): testLexer.g4:11:6: syntax error: '@' came as a complete surprise to me
error(50): testLexer.g4:11:9: syntax error: ']' came as a complete surprise to me