[O] buglet in org-babel-expand-body:R ?

[Charles C. Berry]

org-babel-expand-body:R has this arglist:

        (body params &optional &graphics-file)

which seems to work OK.

But edebug does not like it. The error message is:

 edebug-syntax-error: Invalid read syntax: "Failed matching"...

when I try to instrument the function.

Unless somebody can point me toward a rationale for the `&' prefixed to 
`graphics-file', I will remove it.

Chuck