[ASN.1] Is this a legal SEQUENCE ?

[Ed Day]

Hi,   I have come across the following definition in a spec which I believe to be legal:   MAP-AcceptInfo ::= SEQUENCE {  ...,  extensionContainer ExtensionContainer OPTIONAL  -- extensionContainer must not be used in version 2  } Yet, this does not seem parsable by the rules as currently stated in X.680.   When decomposed, the rule for SequenceType would appear to have only two possibilities for a type starting with an extension marker:   SEQUENCE { ExtensionAndException OptionalExtensionMarker }   or (via ComponentTypeLists):   SEQUENCE { ExtensionAndException ExtensionAdditions ExtensionEndMarker , RootComponentTypeList }   It does not appear that either of these allows the above construct to be handled.  Is the type definition wrong or are the rules wrong or am I missing something?  (and yes, I went back to read the Corrigenda to see if this was corrected anywhere).   Regards,   Ed Day Principal Engineer Objective Systems, Inc. [EMAIL PROTECTED] (484) 875-3020 (main) (610) 608-4930 (mobile) (610) 321-0361 (fax) (877) 307-6855 (toll-free)