Fix crash/hang in Parser::newClosureName

The parser was updating a static std::map without a lock.
It looks like this is supposed to be local to a file anyway,
so add the map as a member of ParserBase.

hphp/util/parser/parser.cpp

@@ -53,8 +53,7 @@ std::string ParserBase::newClosureName(
   }
   name += funcName;
 
-  static std::map<std::string, int> s_seenClosures;
-  int id = ++s_seenClosures[name];
+  int id = ++m_seenClosures[name];
   if (id > 1) {
     // we've seen the same name before, uniquify
     name = name + '#' + std::to_string(id);

hphp/util/parser/parser.h

@@ -199,6 +199,7 @@ protected:
   bool m_nsFileScope;
   std::string m_namespace; // current namespace
   hphp_string_imap<std::string> m_aliases;
+  hphp_string_imap<int> m_seenClosures;
 };
 
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