HasCustomAttribute tag value 19 in FSharp.Core.dll

In FSharp.Core.dll (4.0.30319.1) I found HasCustomAttribute tag with value 19. This value is not specified in ECMA-335. ECMA-335 (Part II, 24.2.6) describes only values from 0 to 18.

Anybody knows what mean with value?

Update:

Seems like tag (19) specify Ge开发者_StackOverflow中文版nericParamTable.

Core.EqualityConditionalOnAttribute Class

Collections.Map<'Key,'Value> Class

but 6th version of Reflector does not show attributes on generic parameters of FSharp.Core.Collections.FSharpMap type.

Update 2:

Question is closed. Answer in 5th edition of ECMA-335. (I used 4th edition).

ECMA 335 5th edition specifies 19 as GenericParam. Partition II Section 22.20 has this to say about it:

The GenericParam table stores the generic parameters used in generic type definitions and generic method definitions. These generic parameters can be constrained (i.e., generic arguments shall extend some class and/or implement certain interfaces) or unconstrained. (Such constraints are stored in the GenericParamConstraint table.)