diff --git a/libtrellis/tools/wasmexcept.hpp b/libtrellis/tools/wasmexcept.hpp
index 657d9dc..ab89553 100644
--- a/libtrellis/tools/wasmexcept.hpp
+++ b/libtrellis/tools/wasmexcept.hpp
@@ -11,9 +11,13 @@
 }
 
 namespace boost {
+struct source_location;
 void throw_exception(std::exception const &e) { 
 	std::cerr << "boost::exception(): " << e.what() << std::endl;
 }
+void throw_exception(std::exception const &e, boost::source_location const &) { 
+	std::cerr << "boost::exception(): " << e.what() << std::endl;
+}
 } // namespace boost
 
 #endif