Packages and shadowing

[Laura Bagnall <LAURA at MIT-MC>]

But it DIDN'T query me when I redefined a global function.  My file
redefined ARRAY-DIMENSIONS and when I loaded the file into my new
package SCHEME without shadowing it, it redefined the global function
without querying me.  ARRAY-DIMENSIONS is a very low-level function and
I was not able to recover without rebooting.  When I included 
(shadow array-dimensions) in my PACKAGE-DECLARE the problem went away.
I am sure that the redefined function was put into the global package
because when I INSPECTED global:array-dimensions it had my file-name
listed as the source.