goto into construct that is optimized away

[jkeenan]

As part of my research on Fatalization of currently deprecated goto
construct I have been
re-reading our current documentation of goto in blead and have been trying
to locate in our test suite examples of each claim made in that documentation.
What we find -- or fail to find -- there will have an impact on the
documentation updates provided as part of a pull request like the current
#23782. I've posted the preliminary results
of that documentation review
here.

This is the eighth in a series of GH issues addressing the items which I
believe are lacking in that documentation.

perldoc -f goto states:

["goto LABEL"] also can't be used to go into a construct that is
optimized away.

What would be an example of a "construct" that is optimized away?

Do we have any tests of such constructs anywhere in the test suite?

How would we adapt such a test to the case of goto LABEL?

[mauke]

What would be an example of a "construct" that is optimized away?

Off the top of my head:

goto FOO;
if (0) {
    FOO: print "oops\n";
}

If a condition is known to be false at compile time, the parser throws the whole if block away AFAIK.