In the latest CVS M-. became slightly more convenient.
It’s now able to find definitions of symbols whose names are prefixed with punctuation, for example, some lisps produces warnings

In FOO: Undeclared free variable X

And pressing M-. on FOO tried to find “FOO:” before, now it sees that there’s no symbol named “FOO:”, it tries to find “FOO”.

This is controlled by two new variables, which can be customized in ~/.swank.lisp

*find-definitions-right-trim*, default value “,:.”
*find-definitions-left-trim*, default value “#:”.

All those are arguments to cl:string-x-trim.

With the default value for left-trim it’s now possible to use M-. on
#: symbols in package definitions.