alexlandau/antlr-preferring-later-rule

Repro of what looks like a bug in ANTLR

antlr-preferring-later-rule

Repro of what looks like a bug in ANTLR

Given the following ANTLR parsing rule:

expression : ID
  | expression LESS_THAN ID GREATER_THAN LPAREN ID RPAREN
  | expression LESS_THAN expression // < operator
  | expression GREATER_THAN expression // > operator
  | LPAREN expression RPAREN
  ;

... I'd expect the string foo<bar>(baz) to match on the second rule (expression LESS_THAN ID GREATER_THAN LPAREN ID RPAREN). Instead, it parses as (essentially) (foo < bar) > (baz).

There are four tests, each for a variant of the rule (two fail, two work as intended). Run them with ./gradlew test.

Per the discussion at antlr/antlr4#866, this may be a known issue that isn't going to be fixed.