diff --git a/runtime/Java/src/org/antlr/v4/runtime/Recognizer.java b/runtime/Java/src/org/antlr/v4/runtime/Recognizer.java
index e869bfb5f..7f5a7d1c3 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/Recognizer.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/Recognizer.java
@@ -226,7 +226,7 @@ public class Recognizer<ATNInterpreter> {
 	public void action(RuleContext _localctx, int ruleIndex, int actionIndex) {
 	}
 
-	public ParserRuleContext args(RuleContext _localctx, int s, int ruleIndex, int actionIndex) {
+	public ParserRuleContext newContext(RuleContext _localctx, int s, int ruleIndex, int actionIndex) {
 		return new ParserRuleContext(_localctx, s);
 	}
 }
diff --git a/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java b/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
index 01444e2c1..eb76417b4 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
@@ -94,8 +94,9 @@ public class ParserATNSimulator extends ATNSimulator {
 	{
 		if ( originalContext==null ) originalContext = RuleContext.EMPTY;
 		RuleContext ctx = RuleContext.EMPTY;
-		if ( useContext  ) ctx = originalContext;
-		OrderedHashSet<ATNConfig> s0_closure = computeStartState(dfa.atnStartState, ctx, originalContext);
+		if ( useContext ) ctx = originalContext;
+		OrderedHashSet<ATNConfig> s0_closure =
+			computeStartState(dfa.atnStartState, ctx, originalContext);
 		dfa.s0 = addDFAState(dfa, s0_closure);
 		if ( prevAccept!=null ) {
 			dfa.s0.isAcceptState = true;
@@ -300,7 +301,7 @@ public class ParserATNSimulator extends ATNSimulator {
 			OrderedHashSet<ATNConfig> tmp = reach;
 			reach = closure;
 			closure = tmp;
-			reach.clear();
+			reach.clear(); // THIS MIGHT BE SLOW! kills each element; realloc might be faster
 		} while ( true );
 
 		if ( prevAccept==null ) {
@@ -457,7 +458,7 @@ public class ParserATNSimulator extends ATNSimulator {
 			RuleContext newContext;
 			if ( parser != null ) {
 				System.out.println("rule trans to rule "+parser.getRuleNames()[t.target.ruleIndex]);
-				newContext = parser.args(config.context, t.target.stateNumber, t.target.ruleIndex, -999);
+				newContext = parser.newContext(config.context, t.target.stateNumber, t.target.ruleIndex, -999);
 				newContext.invokingState = p.stateNumber;
 				System.out.println("new ctx type is "+newContext.getClass().getSimpleName());
 			}
diff --git a/tool/playground/T.g b/tool/playground/T.g
index 2329cc431..8030e5705 100644
--- a/tool/playground/T.g
+++ b/tool/playground/T.g
@@ -1,56 +1,14 @@
 grammar T;
-options {output=AST;}
-s : e EOF ;
-expressionList
-    :   e (','! e)*
-    ;
-e   :   '('! e ')'!
-    |   'this' 
-    |   'super'
-    |   INT
-    |   ID
-    |   type '.'^ 'class'
-    |   e '.'^ ID
-    |   e '.'^ 'this'
-    |   e '.'^ 'super' '('^ expressionList? ')'!
-    |   e '.'^ 'new'^ ID '('! expressionList? ')'!
-	 |	 'new'^ type ( '(' expressionList? ')'! | ('[' e ']'!)+)
-    |   e '['^ e ']'!
-    |   '('^ type ')'! e
-    |   e ('++'^ | '--'^)
-    |   e '('^ expressionList? ')'!
-    |   ('+'^|'-'^|'++'^|'--'^) e
-    |   ('~'^|'!'^) e
-    |   e ('*'^|'/'^|'%'^) e
-    |   e ('+'^|'-'^) e
-    |   e ('<'^ '<' | '>'^ '>' '>' | '>'^ '>') e
-    |   e ('<='^ | '>='^ | '>'^ | '<'^) e
-    |   e 'instanceof'^ e
-    |   e ('=='^ | '!='^) e
-    |   e '&'^ e
-    |   e '^'<assoc=right>^ e
-    |   e '|'^ e
-    |   e '&&'^ e
-    |   e '||'^ e
-    |   e '?' e ':' e
-    |   e ('='<assoc=right>^
-          |'+='<assoc=right>^
-          |'-='<assoc=right>^
-          |'*='<assoc=right>^
-          |'/='<assoc=right>^
-          |'&='<assoc=right>^
-          |'|='<assoc=right>^
-          |'^='<assoc=right>^
-          |'>>='<assoc=right>^
-          |'>>>='<assoc=right>^
-          |'<<='<assoc=right>^
-          |'%='<assoc=right>^) e
-    ;
-type: ID 
-    | ID '['^ ']'!
-    | 'int'
-	 | 'int' '['^ ']'! 
-    ;
-ID : ('a'..'z'|'A'..'Z'|'_'|'$')+;
-INT : '0'..'9'+ ;
-WS : (' '|'\n') {skip();} ;
+
+s : e[9] {true}? ';' ;
+
+e[int i]
+  : {$i>=0}? ID
+  | ID '!'
+  ;
+
+foo[int j] : e[8] {$j==2}? '$' ; // not called but in FOLLOW(e)
+
+ID : 'a'..'z'+;
+
+WS : ' '+ {skip();} ;
diff --git a/tool/resources/org/antlr/v4/tool/templates/codegen/Java/Java.stg b/tool/resources/org/antlr/v4/tool/templates/codegen/Java/Java.stg
index b63a3bc39..24a734843 100644
--- a/tool/resources/org/antlr/v4/tool/templates/codegen/Java/Java.stg
+++ b/tool/resources/org/antlr/v4/tool/templates/codegen/Java/Java.stg
@@ -65,10 +65,10 @@ public class <parser.name> extends Parser {
 
 dumpActions(recog, argFuncs, actionFuncs, sempredFuncs) ::= <<
 <if(argFuncs)>
-	public ParserRuleContext args(RuleContext _localctx, int s, int ruleIndex, int actionIndex) {
+	public ParserRuleContext newContext(RuleContext _localctx, int s, int ruleIndex, int actionIndex) {
 		switch ( ruleIndex ) {
 		    <recog.argFuncs.values:{f|
-case <f.ruleIndex> : return <f.name>_arg((<f.ctxType>)_localctx, s, actionIndex);}; separator="\n">
+case <f.ruleIndex> : return <f.name>_argEval((<f.ctxType>)_localctx, s, actionIndex);}; separator="\n">
     	}
 		return new ParserRuleContext(_localctx, s);
 	}
@@ -104,7 +104,7 @@ public <p.name>(TokenStream input) {
 
 RuleArgFunction(r, actions) ::= <<
 /** arg computations for rules called FROM and evaluated in context of <r.name> */
-public ParserRuleContext <r.name>_arg(ParserRuleContext _localctx, int s, int actionIndex) {
+public ParserRuleContext <r.name>_argEval(ParserRuleContext _localctx, int s, int actionIndex) {
 	switch ( actionIndex ) {
 		<actions:{index|
 case <index> : return new <r.actions.(index).ctxType>(_localctx, s, <actions.(index)>);}; separator="\n">
diff --git a/tool/src/org/antlr/v4/parse/GrammarTreeVisitor.g b/tool/src/org/antlr/v4/parse/GrammarTreeVisitor.g
index 172219d88..08fdfd9bc 100644
--- a/tool/src/org/antlr/v4/parse/GrammarTreeVisitor.g
+++ b/tool/src/org/antlr/v4/parse/GrammarTreeVisitor.g
@@ -253,6 +253,7 @@ rule
 @init {
 List<GrammarAST> mods = new ArrayList<GrammarAST>();
 List<GrammarAST> actions = new ArrayList<GrammarAST>(); // track roots
+currentOuterAltNumber=0;
 }
 	:   ^(	RULE ID {currentRuleName=$ID.text; currentRuleAST=$RULE;}
 			DOC_COMMENT? (^(RULEMODIFIERS (m=ruleModifier{mods.add($m.start);})+))?
@@ -308,8 +309,7 @@ ruleModifier
     ;
 
 ruleBlock
-    :	{currentOuterAltNumber=0;}
-    	^(	BLOCK
+    :	^(	BLOCK
     		(	{
     			currentOuterAltRoot = (GrammarAST)input.LT(1);
 				currentOuterAltNumber++;