Index: src/SynTree/TypeSubstitution.h
===================================================================
--- src/SynTree/TypeSubstitution.h	(revision 8217e8fb39e467042f9fbdd33aea43d4644c44db)
+++ src/SynTree/TypeSubstitution.h	(revision d104b0259d2af56d64a4f024802ad2afa0236505)
@@ -111,5 +111,5 @@
 				} // if
 			} else {
-				throw SemanticError( "Attempt to provide non-type parameter for type parameter", formal );
+				throw SemanticError( toString( "Attempt to provide non-type parameter: ", toString( *actualIt ).c_str(), " for type parameter " ), formal );
 			} // if
 		} else {