Index: src/ResolvExpr/RenameVars.cc
===================================================================
--- src/ResolvExpr/RenameVars.cc	(revision c66254e1a876dbcd46b647136bf10d44b9645140)
+++ src/ResolvExpr/RenameVars.cc	(revision 02fdb8eb4c22b14a7fc7116a96f53d73dae71205)
@@ -10,6 +10,6 @@
 // Created On       : Sun May 17 12:05:18 2015
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Wed Mar  2 17:36:32 2016
-// Update Count     : 5
+// Last Modified On : Tue Apr 30 17:07:57 2019
+// Update Count     : 7
 //
 
@@ -39,5 +39,5 @@
 		  private:
 			int level, resetCount;
-			std::list< std::map< std::string, std::string > > mapStack;
+			std::list< std::unordered_map< std::string, std::string > > mapStack;
 		};
 
@@ -55,5 +55,5 @@
 	namespace {
 		RenameVars::RenameVars() : level( 0 ), resetCount( 0 ) {
-			mapStack.push_front( std::map< std::string, std::string >() );
+			mapStack.push_front( std::unordered_map< std::string, std::string >() );
 		}
 
@@ -65,5 +65,5 @@
 		void RenameVars::previsit( TypeInstType * instType ) {
 			previsit( (Type *)instType );
-			std::map< std::string, std::string >::const_iterator i = mapStack.front().find( instType->name );
+			std::unordered_map< std::string, std::string >::const_iterator i = mapStack.front().find( instType->name );
 			if ( i != mapStack.front().end() ) {
 				instType->name = i->second;
Index: src/ResolvExpr/TypeEnvironment.h
===================================================================
--- src/ResolvExpr/TypeEnvironment.h	(revision c66254e1a876dbcd46b647136bf10d44b9645140)
+++ src/ResolvExpr/TypeEnvironment.h	(revision 02fdb8eb4c22b14a7fc7116a96f53d73dae71205)
@@ -9,7 +9,7 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 12:24:58 2015
-// Last Modified By : Aaron B. Moss
-// Last Modified On : Mon Jun 18 11:58:00 2018
-// Update Count     : 4
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Tue Apr 30 23:04:10 2019
+// Update Count     : 9
 //
 
@@ -18,6 +18,7 @@
 #include <iostream>                    // for ostream
 #include <list>                        // for list, list<>::iterator, list<>...
-#include <map>                         // for map, map<>::value_compare
-#include <set>                         // for set
+#include <map>						   // for map, map<>::value_compare
+#include <unordered_map>
+#include <set>						   // for set
 #include <string>                      // for string
 #include <utility>                     // for move, swap
@@ -64,6 +65,6 @@
 		AssertionSetValue() : isUsed(false), resnSlot(0) {}
 	};
-	typedef std::map< DeclarationWithType*, AssertionSetValue, AssertCompare > AssertionSet;
-	typedef std::map< std::string, TypeDecl::Data > OpenVarSet;
+	typedef std::map< DeclarationWithType *, AssertionSetValue, AssertCompare > AssertionSet;
+	typedef std::unordered_map< std::string, TypeDecl::Data > OpenVarSet;
 
 	/// merges one set of open vars into another