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Read old(this) in a precondition as the state before the call - #422
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The state machine builder passed preconditions such as "closed(this) && connected(old(this))" to the solver with old() still in them, so building the machine failed and errors on such classes got no hints, category or state context. Replace old(this) with the state before the call, as the verifier does when it checks the call. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
rcosta358
approved these changes
Oct 25, 2026
CatarinaGamboa
marked this pull request as draft
October 26, 2026 11:32
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Why
The state machine builder sent preconditions that mention
old(this)to the solver without replacingold. One example is the expert DatagramSocket spec'sfrom = "closed(this) && connected(old(this))". The solver failed withGhost 'old' could not be found, and since the analysis is best effort, every state error on such a class lost its hints, its category and (since #421) itsStateErrorContext.The liquidjava-fsm test that checks the verifier's states against the diagram found this.
What
In
StateMachineBuilder.transitionsOf,old(this)in a precondition now means the state before the call, which is howAuxStateHandler.changeStatereads it (changeOldMentions(name, name)).Tests
ErrorStateHintOldInPreconditionwithTestStateHints#oldInAPreconditionIsTheStateBeforeTheCall. It fails without the fix and passes with it. On the fsm DatagramSocket client, the error now gets the path-dependent hint.mvn test: 494 tests pass.🤖 Generated with Claude Code