Index: src/GenPoly/Box.cc
===================================================================
--- src/GenPoly/Box.cc	(revision fea7ca72a864654b68ee68c30d09b8423c12bc64)
+++ src/GenPoly/Box.cc	(revision 540de412b77591cc4fdbb16932060ef6229a3f1d)
@@ -10,5 +10,5 @@
 // Created On       : Mon May 18 07:44:20 2015
 // Last Modified By : Rob Schluntz
-// Last Modified On : Fri Apr 29 12:16:11 2016
+// Last Modified On : Mon May 02 14:49:01 2016
 // Update Count     : 295
 //
@@ -785,5 +785,5 @@
 					} else {
 						/// xxx - should this be an assertion?
-						throw SemanticError( "unbound type variable in application ", appExpr );
+						throw SemanticError( "unbound type variable: " + tyParm->first + " in application ", appExpr );
 					} // if
 				} // if
Index: src/GenPoly/GenPoly.cc
===================================================================
--- src/GenPoly/GenPoly.cc	(revision fea7ca72a864654b68ee68c30d09b8423c12bc64)
+++ src/GenPoly/GenPoly.cc	(revision 540de412b77591cc4fdbb16932060ef6229a3f1d)
@@ -5,10 +5,10 @@
 // file "LICENCE" distributed with Cforall.
 //
-// GenPoly.cc -- 
+// GenPoly.cc --
 //
 // Author           : Richard C. Bilson
 // Created On       : Mon May 18 07:44:20 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Tue Dec 15 16:11:18 2015
+// Last Modified By : Rob Schluntz
+// Last Modified On : Mon May 02 14:53:33 2016
 // Update Count     : 13
 //
@@ -81,5 +81,5 @@
 		return 0;
 	}
-	
+
 	Type *isPolyType( Type *type, const TyVarMap &tyVars, const TypeSubstitution *env ) {
 		if ( TypeInstType *typeInst = dynamic_cast< TypeInstType * >( type ) ) {
@@ -112,5 +112,5 @@
 		return 0;
 	}
-	
+
 	Type *isPolyPtr( Type *type, const TyVarMap &tyVars, const TypeSubstitution *env ) {
 		if ( PointerType *ptr = dynamic_cast< PointerType *>( type ) ) {
@@ -146,5 +146,5 @@
 		return isPolyType( type, env );
 	}
-	
+
 	Type * hasPolyBase( Type *type, const TyVarMap &tyVars, int *levels, const TypeSubstitution *env ) {
 		int dummy;
@@ -192,4 +192,8 @@
 				if ( ! fn || fn->get_name() != std::string("*?") ) return 0;
 				expr = *untypedExpr->begin_args();
+			} else if ( CommaExpr *commaExpr = dynamic_cast< CommaExpr* >( expr ) ) {
+				// copy constructors insert comma exprs, look at second argument which contains the variable
+				expr = commaExpr->get_arg2();
+				continue;
 			} else break;
 
@@ -209,5 +213,5 @@
 		}
 	}
-	
+
 	void printTyVarMap( std::ostream &os, const TyVarMap &tyVarMap ) {
 		for ( TyVarMap::const_iterator i = tyVarMap.begin(); i != tyVarMap.end(); ++i ) {
Index: src/GenPoly/PolyMutator.cc
===================================================================
--- src/GenPoly/PolyMutator.cc	(revision fea7ca72a864654b68ee68c30d09b8423c12bc64)
+++ src/GenPoly/PolyMutator.cc	(revision 540de412b77591cc4fdbb16932060ef6229a3f1d)
@@ -5,10 +5,10 @@
 // file "LICENCE" distributed with Cforall.
 //
-// PolyMutator.cc -- 
+// PolyMutator.cc --
 //
 // Author           : Richard C. Bilson
 // Created On       : Mon May 18 07:44:20 2015
 // Last Modified By : Rob Schluntz
-// Last Modified On : Fri Aug 14 15:28:50 2015
+// Last Modified On : Mon May 02 14:50:58 2016
 // Update Count     : 11
 //
@@ -63,4 +63,5 @@
 				env = expr->get_env();
 			}
+			// xxx - should env be cloned (or moved) onto the result of the mutate?
 			return expr->acceptMutator( *this );
 		} else {
@@ -144,6 +145,6 @@
 		return untypedExpr;
 	}
- 
- 
+
+
 	Initializer *PolyMutator::mutate( SingleInit *singleInit ) {
 		singleInit->set_value( mutateExpression( singleInit->get_value() ) );