=head1 CAVEATS
+Using this pragma will cause a slight global slowdown of any subsequent compilation phase that happens anywere in your code - even outside of the scope of use of C<use Lexical::Types> - which may become noticeable if you rely heavily on numerous calls to C<eval STRING>.
+
The restrictions on the type (being either a defined package name or a constant) apply even if you use the C<'as'> option to redirect to another package, and are unlikely to find a workaround as this happens deep inside the lexer - far from the reach of an extension.
Only one mangler or prefix can be in use at the same time in a given scope.
+Typed lexicals declarations that appear in code C<eval>'d during the global destruction phase of a spawned thread or pseudo-fork (the processes used internally for the C<fork> emulation on Windows) are ignored.
+
The implementation was tweaked to work around several limitations of vanilla C<perl> pragmas : it's thread safe, and doesn't suffer from a C<perl 5.8.x-5.10.0> bug that causes all pragmas to propagate into C<require>d scopes.
With 5.8 perls, the pragma does not propagate into C<eval STRING>.