Description: Replace the HashSets with LinkedHashSets to make the generated parsers reproducible

Author: Emmanuel Bourg <ebourg@apache.org>

Forwarded: no

--- a/tool/src/main/antlr3/org/antlr/grammar/v3/DefineGrammarItemsWalker.g

+++ b/tool/src/main/antlr3/org/antlr/grammar/v3/DefineGrammarItemsWalker.g

@@ -45,6 +45,7 @@

 package org.antlr.grammar.v3;

 import org.antlr.tool.*;

 import java.util.HashSet;

+import java.util.LinkedHashSet;

 import java.util.Set;

 }

@@ -279,7 +280,7 @@

 throwsSpec returns [HashSet<String> exceptions]

 @init

 {

-	$exceptions = new HashSet<String>();

+	$exceptions = new LinkedHashSet<String>();

 }

 	:	^('throws' (ID {$exceptions.add($ID.text);})+ )

 	;

@@ -556,7 +557,7 @@

 	if ( state.backtracking == 0 )

 	{

 		if ( grammar.buildAST() )

-			currentRewriteRule.rewriteRefsDeep = new HashSet<GrammarAST>();

+			currentRewriteRule.rewriteRefsDeep = new LinkedHashSet<GrammarAST>();

 	}

 }

 	:	^(	REWRITES

@@ -582,8 +583,8 @@

 	{

 		// don't do if guessing

 		currentRewriteBlock=$start; // pts to BLOCK node

-		currentRewriteBlock.rewriteRefsShallow = new HashSet<GrammarAST>();

-		currentRewriteBlock.rewriteRefsDeep = new HashSet<GrammarAST>();

+		currentRewriteBlock.rewriteRefsShallow = new LinkedHashSet<GrammarAST>();

+		currentRewriteBlock.rewriteRefsDeep = new LinkedHashSet<GrammarAST>();

 	}

 }

 	:   ^( BLOCK rewrite_alternative EOB )