#2126	Compile-time error

An invalid combination of tests was encountered in a stream type test.

Additional Information

For stream 'X', current keyword is 'Y'.
where X is the name of the stream in the test, and Y is the current keyword which conflicts with keywords already present in the test.

Certain tests make no sense, such as "WHEN STREAM IS (OPEN AND CLOSED)" or "(FILE AND SOURCE-BUFFER)" or "(READER-FUNCTION AND REFERENT AND OPEN)". The compiler does not complain about redundant tests, such as "(OPEN AND OPEN)" or "(FILE AND SINK)".