ponder-lab / Hybridize-Functions-Refactoring / #3310

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main: 88%

Pull #1022

github

Pin the walk's memo with a frame reached along two paths

A frame calling the next one from two sites gives each site its own
node, so the `called_twice` case exercised what `forwarded` already
does. Contexts merge two frames up, though, so a frame above a helper
called twice is reached along two paths in one walk, and the memo is
what keeps the second path from reading as unguarded. The `diamond`
case replaces `called_twice` and fails when the memo is reverted to a
`seen` set.

The walk's Javadoc now says what the memo is for, and notes that a
hopped call counts as guarded whether or not its argument comes from
the guarded call's.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NTnpjPjJj2aZy1ZkUD1eAn

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