Have you heard of local? See source of Web::Scraper, the jist of which is

sub my_outer(&) {
    my( $callback  ) = @_;
    my $stash = {};
    no warnings 'redefine';
## closure
    local *my_inners = sub { ... $stash ... };
    local *foo       = sub { ... $stash ... }; 
    local *result    = sub { ... $stash ... };
    return $callback->( $stash );
}
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