[antlr-interest] Reduce.g generates broken java with antlr-3.4-complete.jar (but not antlr-3.3-complete.jar)

[Toby Nance]

The file walking/patterns/Reduce.g (downloadable for the book "Language
Implementation Patterns" by Terence Parr) produces invalid java code when
using antlr-3.4-complete.jar.

I'm not sure of the rights I have to redistribute the code here, so here's
the code reduced to what still causes the error.

//*********************** start of Reduce.g****

tree grammar Reduce;****

options {****

    tokenVocab=VecMath;      // use tokens from VecMath.g****

    ASTLabelType=CommonTree; // we're using CommonTree nodes****

    output=AST;              // build new ASTs from input AST****

    filter=true;             // tree pattern matching mode****

    backtrack=true;          // allow backtracking if it's needed****

}****

** **

bottomup :  multBy2 ;****

** **

multBy2****

    :   ^('*' x=INT {$x.int==2}? y=.) -> ^(SHIFT["<<"] $y INT["1"])****

    |   ^('*' a=. b=INT {$b.int==2}?) -> ^(SHIFT["<<"] $a INT["1"])****

    ;****

** **

//*********************** end of Reduce.g

**

** **


**Using antlr-3.4, this generates the invalid java code:

 **

    //*** GENERATED WITH 3.4****

** **

    public final void synpred1_Reduce_fragment() throws
RecognitionException {****

        CommonTree =null;****

        CommonTree =null;****

** **

** **

Using antlr-3.3, this generates:

    //*** GENERATED WITH 3.3****

** **

    public final void synpred1_Reduce_fragment() throws
RecognitionException {  ****

        CommonTree x=null;****

        CommonTree y=null;