OCL21 — add ’and’ between both expression parts

8. – [1] An ocl message argument evaluation has either an ocl expression
– evaluation, or an unspecified value expression evaluation, not both.
context OclMessageArgEval inv:
expression->size() = 1 implies unspecified->size() = 0
expression->size() = 0 implies unspecified->size() = 1
==> add ’and’ between both expression parts

Yes. But I cannot check the precedence without reading the spec so use a more obvious exposition