diff --git a/ProgramOptions.h b/ProgramOptions.h
index b50426c..c6edb00 100644
--- a/ProgramOptions.h
+++ b/ProgramOptions.h
@@ -290,7 +290,7 @@ namespace Alepha::Hydrogen  ::detail::  ProgramOptions_m
 					// TODO: This should steal the impl from the vector form, above, and that should defer to this.
 
 					using parse_type= typename arg_type::value_type;
-					auto handler= [handler, name= name]( std::optional< std::string > argument )
+					auto wrapped= [handler, name= name]( std::optional< std::string > argument )
 					{
 						impl::checkArgument( argument, name );
 
@@ -311,7 +311,7 @@ namespace Alepha::Hydrogen  ::detail::  ProgramOptions_m
 						};
 						handler( parsed );
 					};
-					return registerHandler( handler );
+					return registerHandler( wrapped );
 				}
 				else
 				{