David,
The payload isn’t required. Your reading of 7.16.2 is right, and succession flow prepareSandwich.sandwich to eatSandwich.sandwich; with untyped parameters renders correctly on its own. The only change needed is the expose.
Looking at the diagram in your reply, the legend in the lower right reads expose enjoyLunch::* with one asterisk. Two are needed:
view 'Show Succession Flow' : StandardViewDefinitions::GeneralView {
expose enjoyLunch::**;
}
One asterisk exposes only the direct children of enjoyLunch, so prepareSandwich and eatSandwich come through but their sandwich parameters do not. The flow ends then have nothing to attach to, and dropping the separate expose enjoyLunch; line removes the owner that start and done were hanging from, which is why those disappeared too. With ::** and nothing else changed, your original file produces the pins, the direction arrows, and the dashed succession flow.
So the two things you tested were tangled together. Adding the payload also worked, but only because it happened to be tested against the single-asterisk view. Either change alone is enough, and you do not need the payload if the parameter typing is carrying the meaning.
What is still missing is the dashed rendering on the plain successions from start to prepareSandwich and from eatSandwich to done. Those come out solid. That one is a known bug and is being worked on; thanks for identifying this for us!
Finally, usages in packages are a fraught topic, and are tripping a lot of folks up. I created a dedicated topic about what a package-level usage means in Megathread: Package-level usages, with the spec text and the OMG issues.
Adam Layne, PhD