irritability of structure name conflicts

[Dave Mason <dmason@sarg.Ryerson.CA>]

I have the following as part of a type declaration:
	and variable = {name:scheme; mutable value:scheme; next:variable}
	and field = {fname:scheme;
		     fclass:scheme;
		     finit:scheme option;
		     fnext:field}
	and clause = {tags:scheme list;code:scheme list}
	and binding = {id:int;mutable set:bool;value:scheme}

all of which compiles fine, but I get the error:
	The label value belongs to the type Types.binding
	but is here mixed with labels of type Types.variable
at a line that says, in part:
	 {name=sym;value=r;next=symbol_table.(idx)}

I didn't get the error before I added the field type!  I'm (a)
confused, and (b) irritated that I have to keep making up names for
labels!

Is there some way I can force it to interpret the type constructor as
a particular type so that it chooses the labels from the correct set?

Thanks	../Dave