Preserve State in State Refinements without Postcondition#191
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Preserve State in State Refinements without Postcondition#191
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CatarinaGamboa
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Mar 27, 2026
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im surprised the change is so small haha but looks good!
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Closes #51.
Fixes a bug where
@StateRefinementannotations with afromcondition but notocondition were incorrectly treated as state transitions. This caused LiquidJava to weaken object state after calls that should only check a precondition, losing precise information needed by later calls.Root cause
When a state refinement had
from != nullandto == null, the verifier created a post-state by copyingfromintoto, which turned a pure state check into an actual transition. Fixed this by removing this part of the logic.This means that, for example, a method that should only require
x(this) > 0could overwrite a more precise state such asx(this) == 2with the weaker predicatex(this) > 0.