wanted: push/pop declarations or similar

[Nikodemus Siivola]

From sbcl-devel, by Tobias Rittweiler:

Say you want to get rid of compiler-notes for a very specific
area of code inside a macro. However, the following won't cut it:

 `(locally (declare (sb-ext:muffle-conditions sb-ext:compiler-note)
    (with-foo (...)
      (declare (sb-ext:unmuffle-conditions sb-ext:compiler-note))
      ,@body))

The reason why that is not sufficient is because inside WITH-FOO
we'll unconditionally unmuffle compiler-notes even though there
may a global muffling declaration active.

Presumably you can get at the list of currently muffled condition
from a macro's &environment object, so you can probably write the
above as

 (let ((muffled-conditions (get-declaration 'sb-ext:muffle-conditions
env)))
   `(locally (declare (sb-ext:muffle-conditions sb-ext:compiler-note)
      (with-foo (...)
        (declare (sb-ext:unmuffle-conditions sb-ext:compiler-note))
        (declare (sb-ext:muffle-conditions ,@muffled-conditions))
        ,@body)))

I'm wondering if this warrants a new declaration REMUFFLE-CONDITIONS?

[Nikodemus Siivola (nikodemus)]

Similar issue probably affects ENABLE-PACKAGE-LOCKS and DISABLE-PACKAGE-LOCKS.