Index: src/AST/GenericSubstitution.cpp
===================================================================
--- src/AST/GenericSubstitution.cpp	(revision f69fac7faef547c274fcfbc767d8c423a7f3a207)
+++ src/AST/GenericSubstitution.cpp	(revision 4f6dda063e7b3a906904ff494b7cf4bb41f5a5c5)
@@ -45,5 +45,5 @@
 			visit_children = false;
 			const AggregateDecl * aggr = ty->aggr();
-			sub = TypeSubstitution{ aggr->params.begin(), aggr->params.end(), ty->params.begin() };
+			sub = TypeSubstitution( aggr->params, ty->params );
 		}
 
Index: src/AST/TypeSubstitution.hpp
===================================================================
--- src/AST/TypeSubstitution.hpp	(revision f69fac7faef547c274fcfbc767d8c423a7f3a207)
+++ src/AST/TypeSubstitution.hpp	(revision 4f6dda063e7b3a906904ff494b7cf4bb41f5a5c5)
@@ -37,4 +37,6 @@
   public:
 	TypeSubstitution();
+	template< typename FormalContainer, typename ActualContainer >
+	TypeSubstitution( FormalContainer formals, ActualContainer actuals );
 	template< typename FormalIterator, typename ActualIterator >
 	TypeSubstitution( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin );
@@ -76,6 +78,8 @@
 	bool empty() const;
 
+	template< typename FormalContainer, typename ActualContainer >
+	void addAll( FormalContainer formals, ActualContainer actuals );
 	template< typename FormalIterator, typename ActualIterator >
-	void add( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin );
+	void addAll( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin );
 
 	/// create a new TypeSubstitution using bindings from env containing all of the type variables in expr
@@ -112,7 +116,24 @@
 };
 
+template< typename FormalContainer, typename ActualContainer >
+TypeSubstitution::TypeSubstitution( FormalContainer formals, ActualContainer actuals ) {
+	assert( formals.size() == actuals.size() );
+	addAll( formals.begin(), formals.end(), actuals.begin() );
+}
+
+template< typename FormalIterator, typename ActualIterator >
+TypeSubstitution::TypeSubstitution( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin ) {
+	addAll( formalBegin, formalEnd, actualBegin );
+}
+
+template< typename FormalContainer, typename ActualContainer >
+void TypeSubstitution::addAll( FormalContainer formals, ActualContainer actuals ) {
+	assert( formals.size() == actuals.size() );
+	addAll( formals.begin(), formals.end(), actuals.begin() );
+}
+
 // this is the only place where type parameters outside a function formal may be substituted.
 template< typename FormalIterator, typename ActualIterator >
-void TypeSubstitution::add( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin ) {
+void TypeSubstitution::addAll( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin ) {
 	// FormalIterator points to a TypeDecl
 	// ActualIterator points to a Type
@@ -129,16 +150,8 @@
 			} // if
 		} else {
-			
+			// Is this an error?
 		} // if
 	} // for
 }
-
-
-
-template< typename FormalIterator, typename ActualIterator >
-TypeSubstitution::TypeSubstitution( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin ) {
-	add( formalBegin, formalEnd, actualBegin );
-}
-
 
 } // namespace ast