CBMC 5.95.1 crashes on proof of simple array equality function about cbmc HOT 7 CLOSED

In loop contracts, we replace quantified variables with a tmp variable and add the tmp variable to the symbol map. However, the detection of the quantified variables is not complete now: https://github.com/diffblue/cbmc/blob/develop/src/goto-instrument/contracts/utils.cpp#L425. It does not include equal expression. The error doesn't persist once I add the equal expression to the detection.

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As a workaround before the fix is merged, you may want to use the boolean variable arrays_not_match and invariant arrays_not_match != __CPROVER_forall instead.

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Please let me know when this fix is merged.

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I tried inverting the logic and using != instead of ==, but I don't like it because it makes the code much harder to read and understand.

With that change, I get 2 warnings that say "warning: ignoring forall" which are followed by a print out of some syntax tree. What does that mean?

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"warning: ignoring forall"

The SAT backend eagerly grounds quantifiers when domains are small, but ignores them when domains are too large, which is seems to be the case here. You should try using the SMT back-end to solve this example, quantifiers are passed to the SMT back-end and grounded using the solver's heuristics.

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OK. Please improve the error message to make it clearer what's wrong and what the corrective action should be.

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Please let me know when this fix is merged.

#8299 was merged.

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