Need tests that exercise 'goto __SUB__'

[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 second in a series of GH issues addressing the items which I
believe are lacking in that documentation.

perldoc -f goto states that goto:

The "goto EXPR" form expects to evaluate "EXPR" to a code
reference or a label name. If it evaluates to a code reference,
it will be handled like "goto &NAME", below. This is especially
useful for implementing tail recursion via "goto __SUB__".

So far I cannot locate any test in t/op/goto-sub.t that exercises goto __SUB__. Write some.

[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 second in a series of GH issues addressing the items which I believe are lacking in that documentation.

perldoc -f goto states that goto:

The "goto EXPR" form expects to evaluate "EXPR" to a code
reference or a label name. If it evaluates to a code reference,
it will be handled like "goto &NAME", below. This is especially
useful for implementing tail recursion via "goto __SUB__".

So far I cannot locate any test in t/op/goto-sub.t that exercises goto __SUB__. Write some.

@mauke, in #13035 (comment), you wrote:

Experiments suggest that 'goto EXPR' performs a tail call (i.e. is equivalent
to 'goto &{ EXPR }') if EXPR evaluates to a code reference. This should be
documented under 'goto EXPR'.

@rjbs subsequently wrote the documentation I quoted above. Would you be able to resurrect one of your experiments and transform it into a test for t/op/goto-sub.t in blead? Thanks.