Yanking regular expression to regular expression search minibuffer or to regular expression search / replace minibuffer

[glen.d.scott@gmail.com]

   I have tried to yank to a regular expression search replace
minibuffer, and also to a regular expression search minibuffer with M-
y, but am not meeting with success.

   When I yank the text:
[^A-Z0-9_]

  to a regular expression search minibuffer with the shortcut M-y, the
text that is placed in the minibuffer to search for is the text:
\[\^A-Z0-9_]

(note the leading \ characters before the [ and before the ^
characters)

   When I try to yank the same regexp to the search replace
minibuffer, I get an error:
Previous command was not a yank

and the text does not get yanked into the minibuffer at all.

   What is the way to yank a regular expression into the regular
expression search minibuffer, or even better, into the search /
replace minibuffer?

Thanks,
Glen Scott