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fix: circuit simplify and extens must not prove false judgements - #1203
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Two circuit tactics proved false hoare judgements.
`circuit simplify` replaced each bitstring / array equality of the
postcondition by `true` when the circuits prove it valid, and by
`false` otherwise. An equality that is not valid may still hold in
some states, so this is unsound under a negation. With
proc f(x : W8) = { return x; }
it proved
hoare[M.f : true ==> !(res = of_int 0)]
An equality that the circuits do not prove valid is now kept as is.
`extens [x]` replaces `x` by each of its values in the program, the
precondition and the postcondition, but the postcondition reads `x` in
the final memory. With
proc f(x : W8) = { x <- of_int 0; return x; }
it proved
hoare[M.f : x = of_int 1 ==> res = of_int 1]
It now fails when the program writes `x`.
Fixes #1201.
Fixes #1202.
Origin: e07ffa0 (2026-06-24), first released in r2026.07.
Test: tests/circuits/circuit_soundness.ec (the previous build accepts
the two `fail` lines). tests/circuits, unit (125 files) and stdlib
(128) pass.
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Two circuit tactics proved false hoare judgements.
circuit simplifyreplaced each bitstring / array equality of thepostcondition by
truewhen the circuits prove it valid, and byfalseotherwise. An equality that is not valid may still hold insome states, so this is unsound under a negation. With
it proved
An equality that the circuits do not prove valid is now kept as is.
extens [x]replacesxby each of its values in the program, theprecondition and the postcondition, but the postcondition reads
xinthe final memory. With
it proved
It now fails when the program writes
x.Fixes #1201.
Fixes #1202.
Origin: e07ffa0 (2026-06-24), first released in r2026.07.
Test: tests/circuits/circuit_soundness.ec (the previous build accepts
the two
faillines). tests/circuits, unit (125 files) and stdlib(128) pass.