resolving https://github.com/Theano/Theano/issues/4445

theano/compile/function_module.py

@@ -822,10 +822,14 @@ class Function(object):
 
                     except Exception as e:
                         function_name = "theano function"
+                        argument_name = "argument"
                         if self.name:
-                            function_name += ' with name "' + self.name + '" '
-                        e.args = ("Bad input argument to " + function_name +
-                                  " at index %d(0-based)" % i,) + e.args
+                            function_name += ' with name "' + self.name + '"'
+                        if arg.name:
+                            argument_name += ' with name "' + arg.name + '"'
+                        e.args = ("Bad input " + argument_name + " to "
+                                  + function_name + " at index %d (0-based)"
+                                  % i,) + e.args
                         raise
                 s.provided += 1
                 i += 1