feat(lean): add negated condition to while loop spec#1863
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abentkamp
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maximebuyse
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Jan 13, 2026
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This PR strengthens the specification
Rust_primitives.Hax.while_loop.specof while loops by specifying that the condition is false after exiting the loop. To do this, we convert the condition into a pure function in the same way that we convert the loop invariant and the termination measure. This is necessary to refer to the condition in the postcondition.While experimenting with the new feature, I found that using
decideto convertProptoBoolin the specs of greater-than, less-then, etc. makes more sense than the implicit conversion toPropthat was present in those specs previously.