diff --git a/runtime/Cpp/demo/Mac/antlr4-cpp-demo/main.cpp b/runtime/Cpp/demo/Mac/antlr4-cpp-demo/main.cpp
index 361e4080e..61ad21118 100644
--- a/runtime/Cpp/demo/Mac/antlr4-cpp-demo/main.cpp
+++ b/runtime/Cpp/demo/Mac/antlr4-cpp-demo/main.cpp
@@ -33,6 +33,9 @@ int main(int argc, const char * argv[]) {
   ANTLRInputStream input(L"ab");
   TestLexer lexer(&input);
   CommonTokenStream tokens(&lexer);
+  for (auto token : tokens.getTokens()) {
+    std::cout << token << std::endl;
+  }
 
   TestParser parser(&tokens);
   std::shared_ptr<tree::ParseTree> tree = parser.main();
diff --git a/runtime/Cpp/demo/Mac/antlrcpp.xcodeproj/project.pbxproj b/runtime/Cpp/demo/Mac/antlrcpp.xcodeproj/project.pbxproj
index 323b85ce6..d46ccbd02 100644
--- a/runtime/Cpp/demo/Mac/antlrcpp.xcodeproj/project.pbxproj
+++ b/runtime/Cpp/demo/Mac/antlrcpp.xcodeproj/project.pbxproj
@@ -598,7 +598,7 @@
 		27C666861C9584050021E494 /* LexerInterpreter.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = LexerInterpreter.cpp; path = ../../runtime/LexerInterpreter.cpp; sourceTree = SOURCE_ROOT; };
 		27C666871C9584050021E494 /* LexerInterpreter.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = LexerInterpreter.h; path = ../../runtime/LexerInterpreter.h; sourceTree = SOURCE_ROOT; };
 		27C666881C9584050021E494 /* LexerNoViableAltException.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = LexerNoViableAltException.cpp; path = ../../runtime/LexerNoViableAltException.cpp; sourceTree = SOURCE_ROOT; wrapsLines = 0; };
-		27C666891C9584050021E494 /* LexerNoViableAltException.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = LexerNoViableAltException.h; path = ../../runtime/LexerNoViableAltException.h; sourceTree = SOURCE_ROOT; };
+		27C666891C9584050021E494 /* LexerNoViableAltException.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = LexerNoViableAltException.h; path = ../../runtime/LexerNoViableAltException.h; sourceTree = SOURCE_ROOT; wrapsLines = 0; };
 		27C6668A1C9584050021E494 /* ListTokenSource.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = ListTokenSource.cpp; path = ../../runtime/ListTokenSource.cpp; sourceTree = SOURCE_ROOT; wrapsLines = 0; };
 		27C6668B1C9584050021E494 /* ListTokenSource.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ListTokenSource.h; path = ../../runtime/ListTokenSource.h; sourceTree = SOURCE_ROOT; };
 		27C6668C1C9584050021E494 /* NoViableAltException.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = NoViableAltException.cpp; path = ../../runtime/NoViableAltException.cpp; sourceTree = SOURCE_ROOT; wrapsLines = 0; };
@@ -729,7 +729,7 @@
 		27C668661C9584B60021E494 /* DFA.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DFA.h; sourceTree = "<group>"; };
 		27C668671C9584B60021E494 /* DFASerializer.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = DFASerializer.cpp; sourceTree = "<group>"; wrapsLines = 0; };
 		27C668681C9584B60021E494 /* DFASerializer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DFASerializer.h; sourceTree = "<group>"; };
-		27C668691C9584B60021E494 /* DFAState.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = DFAState.cpp; sourceTree = "<group>"; };
+		27C668691C9584B60021E494 /* DFAState.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = DFAState.cpp; sourceTree = "<group>"; wrapsLines = 0; };
 		27C6686A1C9584B60021E494 /* DFAState.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DFAState.h; sourceTree = "<group>"; };
 		27C6686B1C9584B60021E494 /* LexerDFASerializer.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = LexerDFASerializer.cpp; sourceTree = "<group>"; };
 		27C6686C1C9584B60021E494 /* LexerDFASerializer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = LexerDFASerializer.h; sourceTree = "<group>"; };
diff --git a/runtime/Cpp/runtime/ANTLRErrorListener.h b/runtime/Cpp/runtime/ANTLRErrorListener.h
index 58f981c2b..9bee5ece7 100755
--- a/runtime/Cpp/runtime/ANTLRErrorListener.h
+++ b/runtime/Cpp/runtime/ANTLRErrorListener.h
@@ -108,7 +108,7 @@ namespace runtime {
     /// <param name="configs"> the ATN configuration set where the ambiguity was
     /// determined </param>
     virtual void reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex, bool exact,
-                                 antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) = 0;
+      antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) = 0;
 
     /// <summary>
     /// This method is called when an SLL conflict occurs and the parser is about
@@ -131,7 +131,7 @@ namespace runtime {
     /// <param name="configs"> the ATN configuration set where the SLL conflict was
     /// detected </param>
     virtual void reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                             antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) = 0;
+      antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) = 0;
 
     /// <summary>
     /// This method is called by the parser when a full-context prediction has a
@@ -161,7 +161,7 @@ namespace runtime {
     /// <param name="configs"> the ATN configuration set where the unambiguous prediction
     /// was determined </param>
     virtual void reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                          int prediction, atn::ATNConfigSet *configs) = 0;
+      int prediction, std::shared_ptr<atn::ATNConfigSet> configs) = 0;
   };
 
 } // namespace runtime
diff --git a/runtime/Cpp/runtime/BaseErrorListener.cpp b/runtime/Cpp/runtime/BaseErrorListener.cpp
index cfe3cab8c..1407e332c 100755
--- a/runtime/Cpp/runtime/BaseErrorListener.cpp
+++ b/runtime/Cpp/runtime/BaseErrorListener.cpp
@@ -39,13 +39,13 @@ void BaseErrorListener::syntaxError(IRecognizer *recognizer, Token *offendingSym
 }
 
 void BaseErrorListener::reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                        bool exact, antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) {
+  bool exact, antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) {
 }
 
 void BaseErrorListener::reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex,
-                                                    size_t stopIndex, antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) {
+  size_t stopIndex, antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) {
 }
 
 void BaseErrorListener::reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                                 int prediction, atn::ATNConfigSet *configs) {
+  int prediction, std::shared_ptr<atn::ATNConfigSet> configs) {
 }
diff --git a/runtime/Cpp/runtime/BaseErrorListener.h b/runtime/Cpp/runtime/BaseErrorListener.h
index 471491e3d..ba3dd8595 100755
--- a/runtime/Cpp/runtime/BaseErrorListener.h
+++ b/runtime/Cpp/runtime/BaseErrorListener.h
@@ -45,16 +45,16 @@ namespace runtime {
   class BaseErrorListener : public ANTLRErrorListener {
 
     virtual void syntaxError(IRecognizer *recognizer, Token *offendingSymbol, size_t line, int charPositionInLine,
-                             const std::wstring &msg, std::exception_ptr e) override;
+      const std::wstring &msg, std::exception_ptr e) override;
 
     virtual void reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex, bool exact,
-                                 antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) override;
+      antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
     virtual void reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                             antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) override;
+      antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
     virtual void reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                          int prediction, atn::ATNConfigSet *configs) override;
+      int prediction, std::shared_ptr<atn::ATNConfigSet> configs) override;
   };
 
 } // namespace runtime
diff --git a/runtime/Cpp/runtime/DiagnosticErrorListener.cpp b/runtime/Cpp/runtime/DiagnosticErrorListener.cpp
index 5c35cf2c7..ee4c40142 100755
--- a/runtime/Cpp/runtime/DiagnosticErrorListener.cpp
+++ b/runtime/Cpp/runtime/DiagnosticErrorListener.cpp
@@ -47,7 +47,7 @@ DiagnosticErrorListener::DiagnosticErrorListener(bool exactOnly) : exactOnly(exa
 }
 
 void DiagnosticErrorListener::reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                              bool exact, antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) {
+   bool exact, antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) {
   if (exactOnly && !exact) {
     return;
   }
@@ -61,7 +61,7 @@ void DiagnosticErrorListener::reportAmbiguity(Parser *recognizer, dfa::DFA *dfa,
 }
 
 void DiagnosticErrorListener::reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex,
-                                                          size_t stopIndex, antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) {
+  size_t stopIndex, antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) {
   std::wstring decision = getDecisionDescription(recognizer, dfa);
   std::wstring text = recognizer->getTokenStream()->getText(misc::Interval((int)startIndex, (int)stopIndex));
   std::wstring message = L"reportAttemptingFullContext d = " + decision + L", input = '" + text + L"'";
@@ -69,7 +69,7 @@ void DiagnosticErrorListener::reportAttemptingFullContext(Parser *recognizer, df
 }
 
 void DiagnosticErrorListener::reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex,
-                                                       size_t stopIndex, int prediction, atn::ATNConfigSet *configs) {
+  size_t stopIndex, int prediction, std::shared_ptr<atn::ATNConfigSet> configs) {
   std::wstring decision = getDecisionDescription(recognizer, dfa);
   std::wstring text = recognizer->getTokenStream()->getText(misc::Interval((int)startIndex, (int)stopIndex));
   std::wstring message = L"reportContextSensitivity d = " + decision + L", input = '" + text + L"'";
@@ -93,7 +93,8 @@ std::wstring DiagnosticErrorListener::getDecisionDescription(Parser *recognizer,
   return std::to_wstring(decision) + L"(" + ruleName + L")";
 }
 
-antlrcpp::BitSet *DiagnosticErrorListener::getConflictingAlts(antlrcpp::BitSet *reportedAlts, atn::ATNConfigSet *configs) {
+antlrcpp::BitSet *DiagnosticErrorListener::getConflictingAlts(antlrcpp::BitSet *reportedAlts,
+                                                              std::shared_ptr<atn::ATNConfigSet> configs) {
   if (reportedAlts != nullptr) {
     return reportedAlts;
   }
diff --git a/runtime/Cpp/runtime/DiagnosticErrorListener.h b/runtime/Cpp/runtime/DiagnosticErrorListener.h
index c4768970c..3832629f8 100755
--- a/runtime/Cpp/runtime/DiagnosticErrorListener.h
+++ b/runtime/Cpp/runtime/DiagnosticErrorListener.h
@@ -82,13 +82,13 @@ namespace runtime {
     DiagnosticErrorListener(bool exactOnly);
 
     virtual void reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex, bool exact,
-                                 antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) override;
+      antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
     virtual void reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                             antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) override;
+      antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
     virtual void reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                          int prediction, atn::ATNConfigSet *configs) override;
+      int prediction, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
   protected:
     virtual std::wstring getDecisionDescription(Parser *recognizer, dfa::DFA *dfa);
@@ -103,7 +103,7 @@ namespace runtime {
     /// <param name="configs"> The conflicting or ambiguous configuration set. </param>
     /// <returns> Returns {@code reportedAlts} if it is not {@code null}, otherwise
     /// returns the set of alternatives represented in {@code configs}. </returns>
-    virtual antlrcpp::BitSet *getConflictingAlts(antlrcpp::BitSet *reportedAlts, atn::ATNConfigSet *configs);
+    virtual antlrcpp::BitSet *getConflictingAlts(antlrcpp::BitSet *reportedAlts, std::shared_ptr<atn::ATNConfigSet> configs);
   };
 
 } // namespace runtime
diff --git a/runtime/Cpp/runtime/LexerNoViableAltException.cpp b/runtime/Cpp/runtime/LexerNoViableAltException.cpp
index e1c689ca6..02c9b50a5 100755
--- a/runtime/Cpp/runtime/LexerNoViableAltException.cpp
+++ b/runtime/Cpp/runtime/LexerNoViableAltException.cpp
@@ -38,7 +38,8 @@
 
 using namespace org::antlr::v4::runtime;
 
-LexerNoViableAltException::LexerNoViableAltException(Lexer *lexer, CharStream *input, size_t startIndex, atn::ATNConfigSet *deadEndConfigs)
+LexerNoViableAltException::LexerNoViableAltException(Lexer *lexer, CharStream *input, size_t startIndex,
+                                                     std::shared_ptr<atn::ATNConfigSet> deadEndConfigs)
   : RecognitionException(lexer, input, nullptr, nullptr), _startIndex(startIndex), _deadEndConfigs(deadEndConfigs) {
 }
 
@@ -46,7 +47,7 @@ size_t LexerNoViableAltException::getStartIndex() {
   return _startIndex;
 }
 
-atn::ATNConfigSet* LexerNoViableAltException::getDeadEndConfigs() {
+std::shared_ptr<atn::ATNConfigSet> LexerNoViableAltException::getDeadEndConfigs() {
   return _deadEndConfigs;
 }
 
diff --git a/runtime/Cpp/runtime/LexerNoViableAltException.h b/runtime/Cpp/runtime/LexerNoViableAltException.h
index 90e14bc01..ea1a4fa0e 100755
--- a/runtime/Cpp/runtime/LexerNoViableAltException.h
+++ b/runtime/Cpp/runtime/LexerNoViableAltException.h
@@ -41,10 +41,11 @@ namespace runtime {
 
   class LexerNoViableAltException : public RecognitionException {
   public:
-    LexerNoViableAltException(Lexer *lexer, CharStream *input, size_t startIndex, atn::ATNConfigSet *deadEndConfigs);
+    LexerNoViableAltException(Lexer *lexer, CharStream *input, size_t startIndex,
+                              std::shared_ptr<atn::ATNConfigSet> deadEndConfigs);
 
     virtual size_t getStartIndex();
-    virtual atn::ATNConfigSet* getDeadEndConfigs();
+    virtual std::shared_ptr<atn::ATNConfigSet> getDeadEndConfigs();
     virtual std::wstring toString();
 
   private:
@@ -52,7 +53,7 @@ namespace runtime {
     const size_t _startIndex;
 
     /// Which configurations did we try at input.index() that couldn't match input.LA(1)?
-    atn::ATNConfigSet* _deadEndConfigs;
+    std::shared_ptr<atn::ATNConfigSet> _deadEndConfigs;
     
   };
 
diff --git a/runtime/Cpp/runtime/NoViableAltException.cpp b/runtime/Cpp/runtime/NoViableAltException.cpp
index 2beb8f9f5..f3d3ea977 100755
--- a/runtime/Cpp/runtime/NoViableAltException.cpp
+++ b/runtime/Cpp/runtime/NoViableAltException.cpp
@@ -36,12 +36,12 @@
 using namespace org::antlr::v4::runtime;
 
 NoViableAltException::NoViableAltException(Parser *recognizer)
-  : NoViableAltException(recognizer, recognizer->getInputStream(), recognizer->getCurrentToken(), recognizer->getCurrentToken(),
-                         nullptr, recognizer->ctx) {
+  : NoViableAltException(recognizer, recognizer->getInputStream(), recognizer->getCurrentToken(),
+                         recognizer->getCurrentToken(), nullptr, recognizer->ctx) {
 }
 
 NoViableAltException::NoViableAltException(Parser *recognizer, TokenStream *input, Token *startToken,
-  Token *offendingToken, atn::ATNConfigSet *deadEndConfigs, ParserRuleContext *ctx)
+  Token *offendingToken, std::shared_ptr<atn::ATNConfigSet> deadEndConfigs, ParserRuleContext *ctx)
   : RecognitionException(recognizer, input, ctx, offendingToken), _deadEndConfigs(deadEndConfigs), _startToken(startToken) {
 }
 
@@ -49,6 +49,6 @@ Token* NoViableAltException::getStartToken() const {
   return _startToken;
 }
 
-atn::ATNConfigSet* NoViableAltException::getDeadEndConfigs() const {
+std::shared_ptr<atn::ATNConfigSet> NoViableAltException::getDeadEndConfigs() const {
   return _deadEndConfigs;
 }
diff --git a/runtime/Cpp/runtime/NoViableAltException.h b/runtime/Cpp/runtime/NoViableAltException.h
index 773712cd5..0e13b428a 100755
--- a/runtime/Cpp/runtime/NoViableAltException.h
+++ b/runtime/Cpp/runtime/NoViableAltException.h
@@ -48,14 +48,14 @@ namespace runtime {
   public:
     NoViableAltException(Parser *recognizer); // LL(1) error
     NoViableAltException(Parser *recognizer, TokenStream *input, Token *startToken, Token *offendingToken,
-                         atn::ATNConfigSet *deadEndConfigs, ParserRuleContext *ctx);
+                         std::shared_ptr<atn::ATNConfigSet> deadEndConfigs, ParserRuleContext *ctx);
 
     virtual Token* getStartToken() const;
-    virtual atn::ATNConfigSet* getDeadEndConfigs() const;
+    virtual std::shared_ptr<atn::ATNConfigSet> getDeadEndConfigs() const;
 
   private:
     /// Which configurations did we try at input.index() that couldn't match input.LT(1)?
-    atn::ATNConfigSet* _deadEndConfigs;
+    std::shared_ptr<atn::ATNConfigSet>  _deadEndConfigs;
 
     /// The token object at the start index; the input stream might
     /// not be buffering tokens so get a reference to it. (At the
diff --git a/runtime/Cpp/runtime/ProxyErrorListener.cpp b/runtime/Cpp/runtime/ProxyErrorListener.cpp
index c2f9b4ccc..ec182cfb1 100755
--- a/runtime/Cpp/runtime/ProxyErrorListener.cpp
+++ b/runtime/Cpp/runtime/ProxyErrorListener.cpp
@@ -34,21 +34,21 @@
 using namespace org::antlr::v4::runtime;
 
 void ProxyErrorListener::reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                         bool exact, antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) {
+  bool exact, antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) {
   for (auto listener : *delegates) {
     listener->reportAmbiguity(recognizer, dfa, startIndex, stopIndex, exact, ambigAlts, configs);
   }
 }
 
 void ProxyErrorListener::reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex,
-                                                     size_t stopIndex, antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) {
+  size_t stopIndex, antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) {
   for (auto listener : *delegates) {
     listener->reportAttemptingFullContext(recognizer, dfa, startIndex, stopIndex, conflictingAlts, configs);
   }
 }
 
 void ProxyErrorListener::reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                                  int prediction, atn::ATNConfigSet *configs) {
+  int prediction, std::shared_ptr<atn::ATNConfigSet> configs) {
   for (auto listener : *delegates) {
     listener->reportContextSensitivity(recognizer, dfa, startIndex, stopIndex, prediction, configs);
   }
diff --git a/runtime/Cpp/runtime/ProxyErrorListener.h b/runtime/Cpp/runtime/ProxyErrorListener.h
index 32290dba9..b274eeb18 100755
--- a/runtime/Cpp/runtime/ProxyErrorListener.h
+++ b/runtime/Cpp/runtime/ProxyErrorListener.h
@@ -62,13 +62,13 @@ namespace runtime {
     }
 
     virtual void reportAmbiguity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex, bool exact,
-                                 antlrcpp::BitSet *ambigAlts, atn::ATNConfigSet *configs) override;
+                                 antlrcpp::BitSet *ambigAlts, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
     virtual void reportAttemptingFullContext(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                             antlrcpp::BitSet *conflictingAlts, atn::ATNConfigSet *configs) override;
+                                             antlrcpp::BitSet *conflictingAlts, std::shared_ptr<atn::ATNConfigSet> configs) override;
 
     virtual void reportContextSensitivity(Parser *recognizer, dfa::DFA *dfa, size_t startIndex, size_t stopIndex,
-                                          int prediction, atn::ATNConfigSet *configs) override;
+                                          int prediction, std::shared_ptr<atn::ATNConfigSet> configs) override;
   };
 
 } // namespace runtime
diff --git a/runtime/Cpp/runtime/atn/ATNConfigSet.cpp b/runtime/Cpp/runtime/atn/ATNConfigSet.cpp
index d9b113a25..87d962333 100755
--- a/runtime/Cpp/runtime/atn/ATNConfigSet.cpp
+++ b/runtime/Cpp/runtime/atn/ATNConfigSet.cpp
@@ -62,7 +62,7 @@ ATNConfigSet::ATNConfigSet(bool fullCtx, std::shared_ptr<ConfigLookup> lookup) :
   InitializeInstanceFields();
 }
 
-ATNConfigSet::ATNConfigSet(ATNConfigSet *old) : ATNConfigSet(old->fullCtx, std::shared_ptr<ConfigLookup>()) {
+ATNConfigSet::ATNConfigSet(std::shared_ptr<ATNConfigSet> old) : ATNConfigSet(old->fullCtx, std::shared_ptr<ConfigLookup>()) {
   addAll(old);
   uniqueAlt = old->uniqueAlt;
   conflictingAlts = old->conflictingAlts;
@@ -106,7 +106,7 @@ bool ATNConfigSet::add(ATNConfig *config, PredictionContextMergeCache *mergeCach
   return true;
 }
 
-bool ATNConfigSet::addAll(ATNConfigSet *other) {
+bool ATNConfigSet::addAll(std::shared_ptr<ATNConfigSet> other) {
   for (auto &c : other->configs) {
     add(c);
   }
@@ -152,19 +152,19 @@ void ATNConfigSet::optimizeConfigs(ATNSimulator *interpreter) {
   }
 }
 
-bool ATNConfigSet::equals(ATNConfigSet *other) {
-  if (other == this) {
+bool ATNConfigSet::operator == (const ATNConfigSet &other) {
+  if (&other == this) {
     return true;
   }
 
   bool configEquals = true;
-  if (configs.size() == other->configs.size()) {
+  if (configs.size() == other.configs.size()) {
     for (size_t i = 0; i < configs.size(); i++) {
-      if (other->configs.size() < i) {
+      if (other.configs.size() < i) {
         configEquals = false;
         break;
       }
-      if (configs[i] != other->configs[i]) {
+      if (configs[i] != other.configs[i]) {
         configEquals = false;
         break;
       }
@@ -173,9 +173,9 @@ bool ATNConfigSet::equals(ATNConfigSet *other) {
     configEquals = false;
   }
 
-  bool same = configs.size() > 0 && configEquals && this->fullCtx == other->fullCtx && this->uniqueAlt == other->uniqueAlt &&
-    this->conflictingAlts == other->conflictingAlts && this->hasSemanticContext == other->hasSemanticContext &&
-    this->dipsIntoOuterContext == other->dipsIntoOuterContext; // includes stack context
+  bool same = configs.size() > 0 && configEquals && fullCtx == other.fullCtx && uniqueAlt == other.uniqueAlt &&
+    conflictingAlts == other.conflictingAlts && hasSemanticContext == other.hasSemanticContext &&
+    dipsIntoOuterContext == other.dipsIntoOuterContext; // includes stack context
 
   return same;
 }
diff --git a/runtime/Cpp/runtime/atn/ATNConfigSet.h b/runtime/Cpp/runtime/atn/ATNConfigSet.h
index 03e4272c1..db428eb9e 100755
--- a/runtime/Cpp/runtime/atn/ATNConfigSet.h
+++ b/runtime/Cpp/runtime/atn/ATNConfigSet.h
@@ -84,7 +84,7 @@ namespace atn {
     const bool fullCtx;
 
     ATNConfigSet(bool fullCtx, std::shared_ptr<ConfigLookup> lookup);
-    ATNConfigSet(ATNConfigSet *old);
+    ATNConfigSet(std::shared_ptr<ATNConfigSet> old);
 
     virtual ~ATNConfigSet();
 
@@ -114,9 +114,9 @@ namespace atn {
 
     virtual void optimizeConfigs(ATNSimulator *interpreter);
 
-    bool addAll(ATNConfigSet *other);
+    bool addAll(std::shared_ptr<ATNConfigSet> other);
 
-    virtual bool equals(ATNConfigSet *other);
+    bool operator == (const ATNConfigSet &other);
     virtual size_t hashCode();
     virtual size_t size();
     virtual bool isEmpty();
diff --git a/runtime/Cpp/runtime/atn/ATNSimulator.cpp b/runtime/Cpp/runtime/atn/ATNSimulator.cpp
index 783f8887a..e22b7447e 100755
--- a/runtime/Cpp/runtime/atn/ATNSimulator.cpp
+++ b/runtime/Cpp/runtime/atn/ATNSimulator.cpp
@@ -40,7 +40,7 @@
 using namespace org::antlr::v4::runtime::dfa;
 using namespace org::antlr::v4::runtime::atn;
 
-DFAState ATNSimulator::ERROR(INT32_MAX);
+const std::shared_ptr<DFAState> ATNSimulator::ERROR = std::make_shared<DFAState>(INT32_MAX);
 
 ATNSimulator::ATNSimulator() {
 }
diff --git a/runtime/Cpp/runtime/atn/ATNSimulator.h b/runtime/Cpp/runtime/atn/ATNSimulator.h
index b6371dc76..9f7c370e9 100755
--- a/runtime/Cpp/runtime/atn/ATNSimulator.h
+++ b/runtime/Cpp/runtime/atn/ATNSimulator.h
@@ -48,7 +48,7 @@ namespace atn {
     ATNSimulator();
 
     /// Must distinguish between missing edge and edge we know leads nowhere.
-    static dfa::DFAState ERROR;
+    static const std::shared_ptr<dfa::DFAState> ERROR;
     ATN atn;
 
     ATNSimulator(const ATN &atn, std::shared_ptr<PredictionContextCache> sharedContextCache);
diff --git a/runtime/Cpp/runtime/atn/LexerATNSimulator.cpp b/runtime/Cpp/runtime/atn/LexerATNSimulator.cpp
index e054e9b22..55c875761 100755
--- a/runtime/Cpp/runtime/atn/LexerATNSimulator.cpp
+++ b/runtime/Cpp/runtime/atn/LexerATNSimulator.cpp
@@ -125,7 +125,7 @@ int LexerATNSimulator::matchATN(CharStream *input) {
 
   size_t old_mode = _mode;
 
-  ATNConfigSet *s0_closure = computeStartState(input, startState);
+  std::shared_ptr<ATNConfigSet> s0_closure = computeStartState(input, startState);
   bool suppressEdge = s0_closure->hasSemanticContext;
   s0_closure->hasSemanticContext = false;
 
@@ -179,7 +179,7 @@ int LexerATNSimulator::execATN(CharStream *input, dfa::DFAState *ds0) {
       target = computeTargetState(input, s, t);
     }
 
-    if (target == &ERROR) {
+    if (target == ERROR.get()) {
       break;
     }
 
@@ -215,7 +215,7 @@ dfa::DFAState *LexerATNSimulator::getExistingTargetState(dfa::DFAState *s, ssize
 }
 
 dfa::DFAState *LexerATNSimulator::computeTargetState(CharStream *input, dfa::DFAState *s, ssize_t t) {
-  OrderedATNConfigSet *reach = new OrderedATNConfigSet();
+  std::shared_ptr<OrderedATNConfigSet> reach = std::make_shared<OrderedATNConfigSet>();
 
   // if we don't find an existing DFA state
   // Fill reach starting from closure, following t transitions
@@ -224,16 +224,16 @@ dfa::DFAState *LexerATNSimulator::computeTargetState(CharStream *input, dfa::DFA
   if (reach->isEmpty()) { // we got nowhere on t from s
                           // we got nowhere on t, don't throw out this knowledge; it'd
                           // cause a failover from DFA later.
-    addDFAEdge(s, t, &ERROR);
+    addDFAEdge(s, t, ERROR.get());
     // stop when we can't match any more char
-    return &ERROR;
+    return ERROR.get();
   }
 
   // Add an edge from s to target DFA found/created for reach
   return addDFAEdge(s, t, reach);
 }
 
-int LexerATNSimulator::failOrAccept(SimState *prevAccept, CharStream *input, ATNConfigSet *reach, ssize_t t) {
+int LexerATNSimulator::failOrAccept(SimState *prevAccept, CharStream *input, std::shared_ptr<ATNConfigSet> reach, ssize_t t) {
   if (prevAccept->dfaState != nullptr) {
     int ruleIndex = prevAccept->dfaState->lexerRuleIndex;
     int actionIndex = prevAccept->dfaState->lexerActionIndex;
@@ -249,7 +249,8 @@ int LexerATNSimulator::failOrAccept(SimState *prevAccept, CharStream *input, ATN
   }
 }
 
-void LexerATNSimulator::getReachableConfigSet(CharStream *input, ATNConfigSet *closure, ATNConfigSet *reach, ssize_t t) {
+void LexerATNSimulator::getReachableConfigSet(CharStream *input, std::shared_ptr<ATNConfigSet> closure,
+                                              std::shared_ptr<ATNConfigSet> reach, ssize_t t) {
   // this is used to skip processing for configs which have a lower priority
   // than a config that already reached an accept state for the same rule
   int skipAlt = ATN::INVALID_ALT_NUMBER;
@@ -313,9 +314,9 @@ atn::ATNState *LexerATNSimulator::getReachableTarget(Transition *trans, ssize_t
   return nullptr;
 }
 
-atn::ATNConfigSet *LexerATNSimulator::computeStartState(CharStream *input, ATNState *p) {
+std::shared_ptr<ATNConfigSet> LexerATNSimulator::computeStartState(CharStream *input, ATNState *p) {
   std::shared_ptr<EmptyPredictionContext> initialContext  = PredictionContext::EMPTY; // ml: the purpose of this assignment is unclear
-  ATNConfigSet *configs = new OrderedATNConfigSet();
+  std::shared_ptr<ATNConfigSet> configs = std::make_shared<OrderedATNConfigSet>();
   for (size_t i = 0; i < p->getNumberOfTransitions(); i++) {
     ATNState *target = p->transition(i)->target;
     LexerATNConfig *c = new LexerATNConfig(target, (int)(i + 1), initialContext);
@@ -324,7 +325,7 @@ atn::ATNConfigSet *LexerATNSimulator::computeStartState(CharStream *input, ATNSt
   return configs;
 }
 
-bool LexerATNSimulator::closure(CharStream *input, LexerATNConfig *config, ATNConfigSet *configs,
+bool LexerATNSimulator::closure(CharStream *input, LexerATNConfig *config, std::shared_ptr<ATNConfigSet> configs,
                                 bool currentAltReachedAcceptState, bool speculative) {
   if (debug) {
     std::wcout << L"closure(" << config->toString(true) << L")" << std::endl;
@@ -382,7 +383,8 @@ bool LexerATNSimulator::closure(CharStream *input, LexerATNConfig *config, ATNCo
   return currentAltReachedAcceptState;
 }
 
-atn::LexerATNConfig *LexerATNSimulator::getEpsilonTarget(CharStream *input, LexerATNConfig *config, Transition *t, ATNConfigSet *configs, bool speculative) {
+atn::LexerATNConfig *LexerATNSimulator::getEpsilonTarget(CharStream *input, LexerATNConfig *config, Transition *t,
+                                                         std::shared_ptr<ATNConfigSet> configs, bool speculative) {
   LexerATNConfig *c = nullptr;
   switch (t->getSerializationType()) {
     case Transition::RULE: {
@@ -469,7 +471,7 @@ void LexerATNSimulator::captureSimState(SimState *settings, CharStream *input, d
   settings->dfaState = dfaState;
 }
 
-dfa::DFAState *LexerATNSimulator::addDFAEdge(dfa::DFAState *from, ssize_t t, ATNConfigSet *q) {
+dfa::DFAState *LexerATNSimulator::addDFAEdge(dfa::DFAState *from, ssize_t t, std::shared_ptr<ATNConfigSet> q) {
   /* leading to this call, ATNConfigSet.hasSemanticContext is used as a
    * marker indicating dynamic predicate evaluation makes this edge
    * dependent on the specific input sequence, so the static edge in the
@@ -512,7 +514,7 @@ void LexerATNSimulator::addDFAEdge(dfa::DFAState *p, ssize_t t, dfa::DFAState *q
   p->edges[(size_t)(t - MIN_DFA_EDGE)] = q; // connect
 }
 
-dfa::DFAState *LexerATNSimulator::addDFAState(ATNConfigSet *configs) {
+dfa::DFAState *LexerATNSimulator::addDFAState(std::shared_ptr<ATNConfigSet> configs) {
   /* the lexer evaluates predicates on-the-fly; by this point configs
    * should not contain any configurations with unevaluated predicates.
    */
diff --git a/runtime/Cpp/runtime/atn/LexerATNSimulator.h b/runtime/Cpp/runtime/atn/LexerATNSimulator.h
index 828d48d58..87344bc39 100755
--- a/runtime/Cpp/runtime/atn/LexerATNSimulator.h
+++ b/runtime/Cpp/runtime/atn/LexerATNSimulator.h
@@ -155,20 +155,20 @@ namespace atn {
     /// returns <seealso cref="#ERROR"/>. </returns>
     virtual dfa::DFAState *computeTargetState(CharStream *input, dfa::DFAState *s, ssize_t t);
 
-    virtual int failOrAccept(SimState *prevAccept, CharStream *input, ATNConfigSet *reach, ssize_t t);
+    virtual int failOrAccept(SimState *prevAccept, CharStream *input, std::shared_ptr<ATNConfigSet> reach, ssize_t t);
 
     /// <summary>
     /// Given a starting configuration set, figure out all ATN configurations
     ///  we can reach upon input {@code t}. Parameter {@code reach} is a return
     ///  parameter.
     /// </summary>
-    void getReachableConfigSet(CharStream *input, ATNConfigSet *closure, ATNConfigSet *reach, ssize_t t);
+    void getReachableConfigSet(CharStream *input, std::shared_ptr<ATNConfigSet> closure, std::shared_ptr<ATNConfigSet> reach, ssize_t t);
 
     virtual void accept(CharStream *input, int ruleIndex, int actionIndex, size_t index, size_t line, size_t charPos);
 
     virtual ATNState *getReachableTarget(Transition *trans, ssize_t t);
 
-    virtual atn::ATNConfigSet *computeStartState(CharStream *input, ATNState *p);
+    virtual std::shared_ptr<ATNConfigSet> computeStartState(CharStream *input, ATNState *p);
 
     /// <summary>
     /// Since the alternatives within any lexer decision are ordered by
@@ -179,10 +179,12 @@ namespace atn {
     /// </summary>
     /// <returns> {@code true} if an accept state is reached, otherwise
     /// {@code false}. </returns>
-    virtual bool closure(CharStream *input, LexerATNConfig *config, ATNConfigSet *configs, bool currentAltReachedAcceptState, bool speculative);
+    virtual bool closure(CharStream *input, LexerATNConfig *config, std::shared_ptr<ATNConfigSet> configs,
+                         bool currentAltReachedAcceptState, bool speculative);
 
     // side-effect: can alter configs.hasSemanticContext
-    virtual LexerATNConfig *getEpsilonTarget(CharStream *input, LexerATNConfig *config, Transition *t, ATNConfigSet *configs, bool speculative);
+    virtual LexerATNConfig *getEpsilonTarget(CharStream *input, LexerATNConfig *config, Transition *t,
+                                             std::shared_ptr<ATNConfigSet> configs, bool speculative);
 
     /// <summary>
     /// Evaluate a predicate specified in the lexer.
@@ -207,7 +209,7 @@ namespace atn {
     virtual bool evaluatePredicate(CharStream *input, int ruleIndex, int predIndex, bool speculative);
 
     virtual void captureSimState(SimState *settings, CharStream *input, dfa::DFAState *dfaState);
-    virtual dfa::DFAState *addDFAEdge(dfa::DFAState *from, ssize_t t, ATNConfigSet *q);
+    virtual dfa::DFAState *addDFAEdge(dfa::DFAState *from, ssize_t t, std::shared_ptr<ATNConfigSet> q);
     virtual void addDFAEdge(dfa::DFAState *p, ssize_t t, dfa::DFAState *q);
 
     /// <summary>
@@ -216,7 +218,7 @@ namespace atn {
     /// configuration containing an ATN rule stop state. Later, when
     /// traversing the DFA, we will know which rule to accept.
     /// </summary>
-    virtual dfa::DFAState *addDFAState(ATNConfigSet *configs);
+    virtual dfa::DFAState *addDFAState(std::shared_ptr<ATNConfigSet> configs);
 
   public:
     dfa::DFA *getDFA(size_t mode);
diff --git a/runtime/Cpp/runtime/atn/ParserATNSimulator.cpp b/runtime/Cpp/runtime/atn/ParserATNSimulator.cpp
index fb1cad8bd..002ba9f2b 100755
--- a/runtime/Cpp/runtime/atn/ParserATNSimulator.cpp
+++ b/runtime/Cpp/runtime/atn/ParserATNSimulator.cpp
@@ -99,8 +99,8 @@ int ParserATNSimulator::adaptivePredict(TokenStream *input, int decision, Parser
         std::wcout << L"predictATN decision " << dfa->decision << L" exec LA(1)==" << getLookaheadName(input) << L", outerContext=" << outerContext->toString(parser) << std::endl;
       }
       bool fullCtx = false;
-      ATNConfigSet *s0_closure = computeStartState(dynamic_cast<ATNState*>(dfa->atnStartState),
-                                                   ParserRuleContext::EMPTY, fullCtx);
+      std::shared_ptr<ATNConfigSet> s0_closure = computeStartState(dynamic_cast<ATNState*>(dfa->atnStartState),
+                                                                   ParserRuleContext::EMPTY, fullCtx);
       dfa->s0 = addDFAState(dfa, new dfa::DFAState(s0_closure));
     }
 
@@ -142,7 +142,7 @@ int ParserATNSimulator::execATN(dfa::DFA *dfa, dfa::DFAState *s0, TokenStream *i
       D = computeTargetState(dfa, previousD, t);
     }
 
-    if (D == &ERROR) {
+    if (D == ERROR.get()) {
       // if any configs in previous dipped into outer context, that
       // means that input up to t actually finished entry rule
       // at least for SLL decision. Full LL doesn't dip into outer
@@ -192,7 +192,7 @@ int ParserATNSimulator::execATN(dfa::DFA *dfa, dfa::DFAState *s0, TokenStream *i
         std::wcout << L"ctx sensitive state " << outerContext << L" in " << D << std::endl;
       }
       bool fullCtx = true;
-      ATNConfigSet *s0_closure = computeStartState(dfa->atnStartState, outerContext, fullCtx);
+      std::shared_ptr<ATNConfigSet> s0_closure = computeStartState(dfa->atnStartState, outerContext, fullCtx);
       reportAttemptingFullContext(dfa, conflictingAlts, D->configs, startIndex, input->index());
       int alt = execATNWithFullContext(dfa, D, s0_closure, input, startIndex, outerContext);
       return alt;
@@ -240,10 +240,10 @@ dfa::DFAState *ParserATNSimulator::getExistingTargetState(dfa::DFAState *previou
 }
 
 dfa::DFAState *ParserATNSimulator::computeTargetState(dfa::DFA *dfa, dfa::DFAState *previousD, ssize_t t) {
-  ATNConfigSet *reach = computeReachSet(previousD->configs, t, false);
+  std::shared_ptr<ATNConfigSet> reach = computeReachSet(previousD->configs, t, false);
   if (reach == nullptr) {
-    addDFAEdge(dfa, previousD, t, &ERROR);
-    return &ERROR;
+    addDFAEdge(dfa, previousD, t, ERROR.get());
+    return ERROR.get();
   }
 
   // create new target state; we'll add to DFA after it's complete
@@ -309,15 +309,15 @@ void ParserATNSimulator::predicateDFAState(dfa::DFAState *dfaState, DecisionStat
   }
 }
 
-int ParserATNSimulator::execATNWithFullContext(dfa::DFA *dfa, dfa::DFAState *D, ATNConfigSet *s0, TokenStream *input,
-                                               size_t startIndex, ParserRuleContext *outerContext) {
+int ParserATNSimulator::execATNWithFullContext(dfa::DFA *dfa, dfa::DFAState *D, std::shared_ptr<ATNConfigSet> s0,
+  TokenStream *input, size_t startIndex, ParserRuleContext *outerContext) {
   if (debug || debug_list_atn_decisions) {
     std::cout << "execATNWithFullContext " << s0 << std::endl;
   }
   bool fullCtx = true;
   bool foundExactAmbig = false;
-  ATNConfigSet *reach = nullptr;
-  ATNConfigSet *previous = s0;
+  std::shared_ptr<ATNConfigSet> reach;
+  std::shared_ptr<ATNConfigSet> previous = s0;
   input->seek(startIndex);
   ssize_t t = input->LA(1);
   int predictedAlt;
@@ -422,12 +422,13 @@ int ParserATNSimulator::execATNWithFullContext(dfa::DFA *dfa, dfa::DFAState *D,
   return predictedAlt;
 }
 
-atn::ATNConfigSet *ParserATNSimulator::computeReachSet(ATNConfigSet *closure, ssize_t t, bool fullCtx) {
+std::shared_ptr<ATNConfigSet> ParserATNSimulator::computeReachSet(std::shared_ptr<ATNConfigSet> closure,
+                                                                  ssize_t t, bool fullCtx) {
   if (debug) {
     std::wcout << L"in computeReachSet, starting closure: " << closure << std::endl;
   }
 
-  ATNConfigSet *intermediate = new ATNConfigSet(fullCtx, std::shared_ptr<ConfigLookup>());
+  std::shared_ptr<ATNConfigSet> intermediate = std::make_shared<ATNConfigSet>(fullCtx, std::shared_ptr<ConfigLookup>());
 
   /* Configurations already in a rule stop state indicate reaching the end
    * of the decision rule (local context) or end of the start rule (full
@@ -472,8 +473,7 @@ atn::ATNConfigSet *ParserATNSimulator::computeReachSet(ATNConfigSet *closure, ss
   }
 
   // Now figure out where the reach operation can take us...
-
-  ATNConfigSet *reach = nullptr;
+  std::shared_ptr<ATNConfigSet> reach;
 
   /* This block optimizes the reach operation for intermediate sets which
    * trivially indicate a termination state for the overall
@@ -502,7 +502,7 @@ atn::ATNConfigSet *ParserATNSimulator::computeReachSet(ATNConfigSet *closure, ss
    * operation on the intermediate set to compute its initial value.
    */
   if (reach == nullptr) {
-    reach = new ATNConfigSet(fullCtx, std::shared_ptr<ConfigLookup>());
+    reach = std::make_shared<ATNConfigSet>(fullCtx, std::shared_ptr<ConfigLookup>());
     std::set<ATNConfig*> closureBusy;
 
     for (auto c : *intermediate->configLookup) {
@@ -553,12 +553,13 @@ atn::ATNConfigSet *ParserATNSimulator::computeReachSet(ATNConfigSet *closure, ss
   return reach;
 }
 
-atn::ATNConfigSet *ParserATNSimulator::removeAllConfigsNotInRuleStopState(ATNConfigSet *configs, bool lookToEndOfRule) {
+std::shared_ptr<ATNConfigSet> ParserATNSimulator::removeAllConfigsNotInRuleStopState(std::shared_ptr<ATNConfigSet> configs,
+  bool lookToEndOfRule) {
   if (PredictionModeClass::allConfigsInRuleStopStates(configs)) {
     return configs;
   }
 
-  ATNConfigSet *result = new ATNConfigSet(configs->fullCtx, std::shared_ptr<ConfigLookup>());
+  std::shared_ptr<ATNConfigSet> result = std::make_shared<ATNConfigSet>(configs->fullCtx, std::shared_ptr<ConfigLookup>());
 
   for (auto config : *configs->configLookup) {
     if (dynamic_cast<RuleStopState*>(config->state) != nullptr) {
@@ -578,10 +579,10 @@ atn::ATNConfigSet *ParserATNSimulator::removeAllConfigsNotInRuleStopState(ATNCon
   return result;
 }
 
-atn::ATNConfigSet *ParserATNSimulator::computeStartState(ATNState *p, RuleContext *ctx, bool fullCtx) {
+std::shared_ptr<ATNConfigSet> ParserATNSimulator::computeStartState(ATNState *p, RuleContext *ctx, bool fullCtx) {
   // always at least the implicit call to start rule
   PredictionContextRef initialContext = PredictionContext::fromRuleContext(atn, ctx);
-  ATNConfigSet *configs = new ATNConfigSet(fullCtx, std::shared_ptr<ConfigLookup>());
+  std::shared_ptr<ATNConfigSet> configs = std::make_shared<ATNConfigSet>(fullCtx, std::shared_ptr<ConfigLookup>());
 
   for (size_t i = 0; i < p->getNumberOfTransitions(); i++) {
     ATNState *target = p->transition(i)->target;
@@ -603,7 +604,7 @@ atn::ATNState *ParserATNSimulator::getReachableTarget(Transition *trans, int tty
 
 // Note that caller must memory manage the returned value from this function
 std::vector<SemanticContextRef> ParserATNSimulator::getPredsForAmbigAlts(BitSet *ambigAlts,
-  ATNConfigSet *configs, size_t nalts) {
+  std::shared_ptr<ATNConfigSet> configs, size_t nalts) {
   // REACH=[1|1|[]|0:0, 1|2|[]|0:1]
   /* altToPred starts as an array of all null contexts. The entry at index i
    * corresponds to alternative i. altToPred[i] may have one of three values:
@@ -670,7 +671,7 @@ std::vector<dfa::DFAState::PredPrediction *> ParserATNSimulator::getPredicatePre
   return pairs;
 }
 
-int ParserATNSimulator::getAltThatFinishedDecisionEntryRule(ATNConfigSet *configs) {
+int ParserATNSimulator::getAltThatFinishedDecisionEntryRule(std::shared_ptr<ATNConfigSet> configs) {
   misc::IntervalSet *alts = nullptr;
   for (auto c : *configs->configLookup) {
     if (c->reachesIntoOuterContext > 0 || (dynamic_cast<RuleStopState*>(c->state) != nullptr && c->context->hasEmptyPath())) {
@@ -713,14 +714,16 @@ BitSet *ParserATNSimulator::evalSemanticContext(std::vector<dfa::DFAState::PredP
   return predictions;
 }
 
-void ParserATNSimulator::closure(ATNConfig *config, ATNConfigSet *configs, std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx) {
+void ParserATNSimulator::closure(ATNConfig *config, std::shared_ptr<ATNConfigSet> configs,
+  std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx) {
   const int initialDepth = 0;
   closureCheckingStopState(config, configs, closureBusy, collectPredicates, fullCtx, initialDepth);
 
   assert(!fullCtx || !configs->dipsIntoOuterContext);
 }
 
-void ParserATNSimulator::closureCheckingStopState(ATNConfig *config, ATNConfigSet *configs, std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx, int depth) {
+void ParserATNSimulator::closureCheckingStopState(ATNConfig *config, std::shared_ptr<ATNConfigSet> configs,
+  std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx, int depth) {
   if (debug) {
     std::wcout << L"closure(" << config->toString(true) << L")" << std::endl;
   }
@@ -770,7 +773,8 @@ void ParserATNSimulator::closureCheckingStopState(ATNConfig *config, ATNConfigSe
   closure_(config, configs, closureBusy, collectPredicates, fullCtx, depth);
 }
 
-void ParserATNSimulator::closure_(ATNConfig *config, ATNConfigSet *configs, std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx, int depth) {
+void ParserATNSimulator::closure_(ATNConfig *config, std::shared_ptr<ATNConfigSet> configs,
+  std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx, int depth) {
   ATNState *p = config->state;
   // optimization
   if (!p->onlyHasEpsilonTransitions()) {
@@ -940,12 +944,12 @@ atn::ATNConfig *ParserATNSimulator::ruleTransition(ATNConfig *config, RuleTransi
   return new atn::ATNConfig(config, t->target, newContext);
 }
 
-BitSet ParserATNSimulator::getConflictingAlts(ATNConfigSet *configs) {
+BitSet ParserATNSimulator::getConflictingAlts(std::shared_ptr<ATNConfigSet> configs) {
   std::vector<BitSet> altsets = PredictionModeClass::getConflictingAltSubsets(configs);
   return PredictionModeClass::getAlts(altsets);
 }
 
-BitSet ParserATNSimulator::getConflictingAltsOrUniqueAlt(ATNConfigSet *configs) {
+BitSet ParserATNSimulator::getConflictingAltsOrUniqueAlt(std::shared_ptr<ATNConfigSet> configs) {
   BitSet conflictingAlts;
   if (configs->uniqueAlt != ATN::INVALID_ALT_NUMBER) {
     conflictingAlts.set((size_t)configs->uniqueAlt);
@@ -997,11 +1001,11 @@ void ParserATNSimulator::dumpDeadEndConfigs(NoViableAltException *nvae) {
 }
 
 NoViableAltException *ParserATNSimulator::noViableAlt(TokenStream *input, ParserRuleContext *outerContext,
-                                                      ATNConfigSet *configs, size_t startIndex) {
+  std::shared_ptr<ATNConfigSet> configs, size_t startIndex) {
   return new NoViableAltException(parser, input, input->get(startIndex), input->LT(1), configs, outerContext);
 }
 
-int ParserATNSimulator::getUniqueAlt(ATNConfigSet *configs) {
+int ParserATNSimulator::getUniqueAlt(std::shared_ptr<ATNConfigSet> configs) {
   int alt = ATN::INVALID_ALT_NUMBER;
   for (auto c : *configs->configLookup) {
     if (alt == ATN::INVALID_ALT_NUMBER) {
@@ -1049,7 +1053,7 @@ dfa::DFAState *ParserATNSimulator::addDFAEdge(dfa::DFA *dfa, dfa::DFAState *from
 }
 
 dfa::DFAState *ParserATNSimulator::addDFAState(dfa::DFA *dfa, dfa::DFAState *D) {
-  if (D == &ERROR) {
+  if (D == ERROR.get()) {
     return D;
   }
 
@@ -1073,8 +1077,8 @@ dfa::DFAState *ParserATNSimulator::addDFAState(dfa::DFA *dfa, dfa::DFAState *D)
   }
 }
 
-void ParserATNSimulator::reportAttemptingFullContext(dfa::DFA *dfa, BitSet *conflictingAlts, ATNConfigSet *configs,
-                                                     size_t startIndex, size_t stopIndex) {
+void ParserATNSimulator::reportAttemptingFullContext(dfa::DFA *dfa, BitSet *conflictingAlts,
+  std::shared_ptr<ATNConfigSet> configs, size_t startIndex, size_t stopIndex) {
   if (debug || retry_debug) {
     misc::Interval interval = misc::Interval((int)startIndex, (int)stopIndex);
     std::wcout << L"reportAttemptingFullContext decision=" << dfa->decision << L":" << configs << L", input=" << parser->getTokenStream()->getText(interval) << std::endl;
@@ -1084,8 +1088,8 @@ void ParserATNSimulator::reportAttemptingFullContext(dfa::DFA *dfa, BitSet *conf
   }
 }
 
-void ParserATNSimulator::reportContextSensitivity(dfa::DFA *dfa, int prediction, ATNConfigSet *configs, size_t startIndex,
-                                                  size_t stopIndex) {
+void ParserATNSimulator::reportContextSensitivity(dfa::DFA *dfa, int prediction, std::shared_ptr<ATNConfigSet> configs,
+  size_t startIndex, size_t stopIndex) {
   if (debug || retry_debug) {
     misc::Interval interval = misc::Interval((int)startIndex, (int)stopIndex);
     std::wcout << L"reportContextSensitivity decision=" << dfa->decision << L":" << configs << L", input=" << parser->getTokenStream()->getText(interval) << std::endl;
@@ -1096,7 +1100,7 @@ void ParserATNSimulator::reportContextSensitivity(dfa::DFA *dfa, int prediction,
 }
 
 void ParserATNSimulator::reportAmbiguity(dfa::DFA *dfa, dfa::DFAState *D, size_t startIndex, size_t stopIndex,
-                                         bool exact, BitSet *ambigAlts, ATNConfigSet *configs) {
+                                         bool exact, BitSet *ambigAlts, std::shared_ptr<ATNConfigSet> configs) {
   if (debug || retry_debug) {
     //			ParserATNPathFinder finder = new ParserATNPathFinder(parser, atn);
     //			int i = 1;
diff --git a/runtime/Cpp/runtime/atn/ParserATNSimulator.h b/runtime/Cpp/runtime/atn/ParserATNSimulator.h
index 4a640ae59..f983cdcdf 100755
--- a/runtime/Cpp/runtime/atn/ParserATNSimulator.h
+++ b/runtime/Cpp/runtime/atn/ParserATNSimulator.h
@@ -353,9 +353,9 @@ namespace atn {
     virtual void predicateDFAState(dfa::DFAState *dfaState, DecisionState *decisionState);
 
     // comes back with reach.uniqueAlt set to a valid alt
-    virtual int execATNWithFullContext(dfa::DFA *dfa, dfa::DFAState *D, ATNConfigSet *s0, TokenStream *input, size_t startIndex, ParserRuleContext *outerContext); // how far we got before failing over
+    virtual int execATNWithFullContext(dfa::DFA *dfa, dfa::DFAState *D, std::shared_ptr<ATNConfigSet> s0, TokenStream *input, size_t startIndex, ParserRuleContext *outerContext); // how far we got before failing over
 
-    virtual ATNConfigSet *computeReachSet(ATNConfigSet *closure, ssize_t t, bool fullCtx);
+    virtual std::shared_ptr<ATNConfigSet> computeReachSet(std::shared_ptr<ATNConfigSet> closure, ssize_t t, bool fullCtx);
 
     /// <summary>
     /// Return a configuration set containing only the configurations from
@@ -376,19 +376,19 @@ namespace atn {
     /// <returns> {@code configs} if all configurations in {@code configs} are in a
     /// rule stop state, otherwise return a new configuration set containing only
     /// the configurations from {@code configs} which are in a rule stop state </returns>
-    virtual ATNConfigSet *removeAllConfigsNotInRuleStopState(ATNConfigSet *configs, bool lookToEndOfRule);
+    virtual std::shared_ptr<ATNConfigSet> removeAllConfigsNotInRuleStopState(std::shared_ptr<ATNConfigSet> configs, bool lookToEndOfRule);
 
-    virtual ATNConfigSet *computeStartState(ATNState *p, RuleContext *ctx, bool fullCtx);
+    virtual std::shared_ptr<ATNConfigSet> computeStartState(ATNState *p, RuleContext *ctx, bool fullCtx);
 
     virtual ATNState *getReachableTarget(Transition *trans, int ttype);
 
     virtual std::vector<SemanticContextRef> getPredsForAmbigAlts(antlrcpp::BitSet *ambigAlts,
-      ATNConfigSet *configs, size_t nalts);
+      std::shared_ptr<ATNConfigSet> configs, size_t nalts);
 
     virtual std::vector<dfa::DFAState::PredPrediction*> getPredicatePredictions(antlrcpp::BitSet *ambigAlts,
       std::vector<SemanticContextRef> altToPred);
 
-    virtual int getAltThatFinishedDecisionEntryRule(ATNConfigSet *configs);
+    virtual int getAltThatFinishedDecisionEntryRule(std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Look through a list of predicate/alt pairs, returning alts for the
@@ -407,14 +407,14 @@ namespace atn {
      ambig detection thought :(
      */
 
-    virtual void closure(ATNConfig *config, ATNConfigSet *configs, std::set<ATNConfig*> &closureBusy,
+    virtual void closure(ATNConfig *config, std::shared_ptr<ATNConfigSet> configs, std::set<ATNConfig*> &closureBusy,
                          bool collectPredicates, bool fullCtx);
 
-    virtual void closureCheckingStopState(ATNConfig *config, ATNConfigSet *configs, std::set<ATNConfig*> &closureBusy,
-                                          bool collectPredicates, bool fullCtx, int depth);
+    virtual void closureCheckingStopState(ATNConfig *config, std::shared_ptr<ATNConfigSet> configs,
+      std::set<ATNConfig*> &closureBusy, bool collectPredicates, bool fullCtx, int depth);
 
     /// Do the actual work of walking epsilon edges.
-    virtual void closure_(ATNConfig *config, ATNConfigSet *configs, std::set<ATNConfig*> &closureBusy,
+    virtual void closure_(ATNConfig *config, std::shared_ptr<ATNConfigSet> configs, std::set<ATNConfig*> &closureBusy,
                           bool collectPredicates, bool fullCtx, int depth);
 
   public:
@@ -432,7 +432,7 @@ namespace atn {
 
     virtual ATNConfig *ruleTransition(ATNConfig *config, RuleTransition *t);
 
-    virtual antlrcpp::BitSet getConflictingAlts(ATNConfigSet *configs);
+    virtual antlrcpp::BitSet getConflictingAlts(std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Sam pointed out a problem with the previous definition, v3, of
@@ -471,7 +471,7 @@ namespace atn {
     /// that we still need to pursue.
     /// </summary>
 
-    virtual antlrcpp::BitSet getConflictingAltsOrUniqueAlt(ATNConfigSet *configs);
+    virtual antlrcpp::BitSet getConflictingAltsOrUniqueAlt(std::shared_ptr<ATNConfigSet> configs);
 
   public:
     virtual std::wstring getTokenName(ssize_t t);
@@ -486,9 +486,10 @@ namespace atn {
     virtual void dumpDeadEndConfigs(NoViableAltException *nvae);
 
   protected:
-    virtual NoViableAltException *noViableAlt(TokenStream *input, ParserRuleContext *outerContext, ATNConfigSet *configs, size_t startIndex);
+    virtual NoViableAltException *noViableAlt(TokenStream *input, ParserRuleContext *outerContext,
+                                              std::shared_ptr<ATNConfigSet> configs, size_t startIndex);
 
-    static int getUniqueAlt(ATNConfigSet *configs);
+    static int getUniqueAlt(std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Add an edge to the DFA, if possible. This method calls
@@ -527,14 +528,16 @@ namespace atn {
     /// state was not already present. </returns>
     virtual dfa::DFAState *addDFAState(dfa::DFA *dfa, dfa::DFAState *D);
 
-    virtual void reportAttemptingFullContext(dfa::DFA *dfa, antlrcpp::BitSet *conflictingAlts, ATNConfigSet *configs,
-                                             size_t startIndex, size_t stopIndex);
+    virtual void reportAttemptingFullContext(dfa::DFA *dfa, antlrcpp::BitSet *conflictingAlts,
+      std::shared_ptr<ATNConfigSet> configs, size_t startIndex, size_t stopIndex);
 
-    virtual void reportContextSensitivity(dfa::DFA *dfa, int prediction, ATNConfigSet *configs, size_t startIndex, size_t stopIndex);
+    virtual void reportContextSensitivity(dfa::DFA *dfa, int prediction, std::shared_ptr<ATNConfigSet> configs,
+                                          size_t startIndex, size_t stopIndex);
 
     /// <summary>
     /// If context sensitive parsing, we know it's ambiguity not conflict </summary>
-    virtual void reportAmbiguity(dfa::DFA *dfa, dfa::DFAState *D, size_t startIndex, size_t stopIndex, bool exact, antlrcpp::BitSet *ambigAlts, ATNConfigSet *configs);
+    virtual void reportAmbiguity(dfa::DFA *dfa, dfa::DFAState *D, size_t startIndex, size_t stopIndex, bool exact,
+                                 antlrcpp::BitSet *ambigAlts, std::shared_ptr<ATNConfigSet> configs);
 
   public:
     void setPredictionMode(PredictionMode mode);
diff --git a/runtime/Cpp/runtime/atn/PredictionMode.cpp b/runtime/Cpp/runtime/atn/PredictionMode.cpp
index f69a55e86..c1c5bdd51 100755
--- a/runtime/Cpp/runtime/atn/PredictionMode.cpp
+++ b/runtime/Cpp/runtime/atn/PredictionMode.cpp
@@ -59,7 +59,7 @@ struct AltAndContextConfigComparer {
   }
 };
 
-bool PredictionModeClass::hasSLLConflictTerminatingPrediction(PredictionMode* mode, ATNConfigSet* configs) {
+bool PredictionModeClass::hasSLLConflictTerminatingPrediction(PredictionMode* mode, std::shared_ptr<ATNConfigSet> configs) {
   /* Configs in rule stop states indicate reaching the end of the decision
    * rule (local context) or end of start rule (full context). If all
    * configs meet this condition, then none of the configurations is able
@@ -76,7 +76,7 @@ bool PredictionModeClass::hasSLLConflictTerminatingPrediction(PredictionMode* mo
     // since we'll often fail over anyway.
     if (configs->hasSemanticContext) {
       // dup configs, tossing out semantic predicates
-      ATNConfigSet* dup = new ATNConfigSet(true, std::shared_ptr<ConfigLookup>());
+      std::shared_ptr<ATNConfigSet> dup = std::make_shared<ATNConfigSet>(true, std::shared_ptr<ConfigLookup>());
       for (ATNConfig config : *configs->configLookup) {
         ATNConfig* c = new ATNConfig(&config, SemanticContext::NONE);
         dup->add(c);
@@ -93,7 +93,7 @@ bool PredictionModeClass::hasSLLConflictTerminatingPrediction(PredictionMode* mo
   return heuristic;
 }
 
-bool PredictionModeClass::hasConfigInRuleStopState(ATNConfigSet* configs) {
+bool PredictionModeClass::hasConfigInRuleStopState(std::shared_ptr<ATNConfigSet> configs) {
   for (ATNConfig c : *configs->configLookup) {
     if (dynamic_cast<RuleStopState*>(c.state) != NULL) {
       return true;
@@ -103,7 +103,7 @@ bool PredictionModeClass::hasConfigInRuleStopState(ATNConfigSet* configs) {
   return false;
 }
 
-bool PredictionModeClass::allConfigsInRuleStopStates(ATNConfigSet* configs) {
+bool PredictionModeClass::allConfigsInRuleStopStates(std::shared_ptr<ATNConfigSet> configs) {
   for (ATNConfig config : *configs->configLookup) {
     if (dynamic_cast<RuleStopState*>(config.state) == NULL) {
       return false;
@@ -170,7 +170,7 @@ antlrcpp::BitSet PredictionModeClass::getAlts(const std::vector<antlrcpp::BitSet
   return all;
 }
 
-std::vector<antlrcpp::BitSet> PredictionModeClass::getConflictingAltSubsets(ATNConfigSet* configs) {
+std::vector<antlrcpp::BitSet> PredictionModeClass::getConflictingAltSubsets(std::shared_ptr<ATNConfigSet> configs) {
   std::unordered_map<ATNConfig *, antlrcpp::BitSet, AltAndContextConfigHasher, AltAndContextConfigComparer> configToAlts;
   for (auto config : *configs->configLookup) {
     configToAlts[config].set((size_t)config->alt);
@@ -182,7 +182,7 @@ std::vector<antlrcpp::BitSet> PredictionModeClass::getConflictingAltSubsets(ATNC
   return values;
 }
 
-std::map<ATNState*, antlrcpp::BitSet> PredictionModeClass::getStateToAltMap(ATNConfigSet* configs) {
+std::map<ATNState*, antlrcpp::BitSet> PredictionModeClass::getStateToAltMap(std::shared_ptr<ATNConfigSet> configs) {
   std::map<ATNState*, antlrcpp::BitSet> m;
   for (ATNConfig c : *configs->configLookup) {
     m[c.state].set((size_t)c.alt);
@@ -190,7 +190,7 @@ std::map<ATNState*, antlrcpp::BitSet> PredictionModeClass::getStateToAltMap(ATNC
   return m;
 }
 
-bool PredictionModeClass::hasStateAssociatedWithOneAlt(ATNConfigSet* configs) {
+bool PredictionModeClass::hasStateAssociatedWithOneAlt(std::shared_ptr<ATNConfigSet> configs) {
   std::map<ATNState*, antlrcpp::BitSet> x = getStateToAltMap(configs);
   for (std::map<ATNState*, antlrcpp::BitSet>::iterator it = x.begin(); it != x.end(); it++){
     if (it->second.count() == 1) return true;
diff --git a/runtime/Cpp/runtime/atn/PredictionMode.h b/runtime/Cpp/runtime/atn/PredictionMode.h
index 7beca5c03..1df81c27d 100755
--- a/runtime/Cpp/runtime/atn/PredictionMode.h
+++ b/runtime/Cpp/runtime/atn/PredictionMode.h
@@ -204,8 +204,7 @@ namespace atn {
     /// the configurations to strip out all of the predicates so that a standard
     /// <seealso cref="ATNConfigSet"/> will merge everything ignoring predicates.
     /// </summary>
-    static bool hasSLLConflictTerminatingPrediction(PredictionMode *mode,
-                                                    ATNConfigSet *configs);
+    static bool hasSLLConflictTerminatingPrediction(PredictionMode *mode, std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Checks if any configuration in {@code configs} is in a
@@ -217,7 +216,7 @@ namespace atn {
     /// <param name="configs"> the configuration set to test </param>
     /// <returns> {@code true} if any configuration in {@code configs} is in a
     /// <seealso cref="RuleStopState"/>, otherwise {@code false} </returns>
-    static bool hasConfigInRuleStopState(ATNConfigSet *configs);
+    static bool hasConfigInRuleStopState(std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Checks if all configurations in {@code configs} are in a
@@ -229,7 +228,7 @@ namespace atn {
     /// <param name="configs"> the configuration set to test </param>
     /// <returns> {@code true} if all configurations in {@code configs} are in a
     /// <seealso cref="RuleStopState"/>, otherwise {@code false} </returns>
-    static bool allConfigsInRuleStopStates(ATNConfigSet *configs);
+    static bool allConfigsInRuleStopStates(std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Full LL prediction termination.
@@ -486,7 +485,7 @@ namespace atn {
     /// alt and not pred
     /// </pre>
     /// </summary>
-    static std::vector<antlrcpp::BitSet> getConflictingAltSubsets(ATNConfigSet *configs);
+    static std::vector<antlrcpp::BitSet> getConflictingAltSubsets(std::shared_ptr<ATNConfigSet> configs);
 
     /// <summary>
     /// Get a map from state to alt subset from a configuration set. For each
@@ -497,9 +496,9 @@ namespace atn {
     /// cref="ATNConfig#alt alt"/>
     /// </pre>
     /// </summary>
-    static std::map<ATNState*, antlrcpp::BitSet> getStateToAltMap(ATNConfigSet *configs);
+    static std::map<ATNState*, antlrcpp::BitSet> getStateToAltMap(std::shared_ptr<ATNConfigSet> configs);
 
-    static bool hasStateAssociatedWithOneAlt(ATNConfigSet *configs);
+    static bool hasStateAssociatedWithOneAlt(std::shared_ptr<ATNConfigSet> configs);
 
     static int getSingleViableAlt(const std::vector<antlrcpp::BitSet> &altsets);
   };
diff --git a/runtime/Cpp/runtime/dfa/DFAState.cpp b/runtime/Cpp/runtime/dfa/DFAState.cpp
index 12b1057ef..f98c8c1e1 100755
--- a/runtime/Cpp/runtime/dfa/DFAState.cpp
+++ b/runtime/Cpp/runtime/dfa/DFAState.cpp
@@ -55,10 +55,11 @@ void DFAState::PredPrediction::InitializeInstanceFields() {
 DFAState::DFAState() : DFAState(-1) {
 }
 
-DFAState::DFAState(int stateNumber) : DFAState(new atn::ATNConfigSet(true, std::shared_ptr<ConfigLookup>()), stateNumber) {
+DFAState::DFAState(int stateNumber) : DFAState(std::make_shared<ATNConfigSet>(true, std::shared_ptr<ConfigLookup>()),
+  stateNumber) {
 }
 
-DFAState::DFAState(atn::ATNConfigSet *configs, int stateNumber) : configs(configs), stateNumber(stateNumber) {
+DFAState::DFAState(std::shared_ptr<ATNConfigSet> configs, int stateNumber) : configs(configs), stateNumber(stateNumber) {
   InitializeInstanceFields();
 }
 
@@ -82,13 +83,13 @@ size_t DFAState::hashCode() {
   return hash;
 }
 
-bool DFAState::equals(DFAState *o) {
+bool DFAState::operator == (const DFAState &o) {
   // compare set of ATN configurations in this set with other
-  if (this == o) {
+  if (this == &o) {
     return true;
   }
 
-  return configs->equals(o->configs);
+  return configs == o.configs;
 }
 
 std::wstring DFAState::toString() {
diff --git a/runtime/Cpp/runtime/dfa/DFAState.h b/runtime/Cpp/runtime/dfa/DFAState.h
index 38f37ea1b..8d8496c95 100755
--- a/runtime/Cpp/runtime/dfa/DFAState.h
+++ b/runtime/Cpp/runtime/dfa/DFAState.h
@@ -78,7 +78,7 @@ namespace dfa {
   public:
     int stateNumber;
 
-    atn::ATNConfigSet *configs;
+    std::shared_ptr<atn::ATNConfigSet> configs;
 
     /// <summary>
     /// {@code edges[symbol]} points to target of symbol. Shift up by 1 so (-1)
@@ -124,7 +124,7 @@ namespace dfa {
     /// Map a predicate to a predicted alternative.
     DFAState();
     DFAState(int stateNumber);
-    DFAState(atn::ATNConfigSet *configs, int stateNumber = -1);
+    DFAState(std::shared_ptr<atn::ATNConfigSet> configs, int stateNumber = -1);
 
     /// <summary>
     /// Get the set of all alts mentioned by all ATN configurations in this
@@ -147,7 +147,7 @@ namespace dfa {
     /// exists that has this exact set of ATN configurations. The
     /// <seealso cref="#stateNumber"/> is irrelevant.
     /// </summary>
-    virtual bool equals(DFAState *o);
+    bool operator == (const DFAState &o);
 
     virtual std::wstring toString();