[Termination Plugin] Extend Expr Support#618
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ArquintL
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@jcp19 This PR adds all expressions that occur in Gobra's unit tests as well as my own project. Might be worth double-checking with Verified SCION whether anything is still missing |
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@ArquintL seems to work with SCION |
marcoeilers
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One comment/question about default or unsupported cases, the rest LGTM.
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@marcoeilers would you mind taking another look please? |
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The termination plugin uses
transformExpto turn preconditions, function bodies, and postconditions into a statement.Each statement is then used as the body of a new method to prove termination for the corresponding expression.
So far, the transformer was not able to handle wildcard permission amounts and forall & existential quantifiers. Additionally, the support for set and multiset-related operations was limited.
This PR extends the transformer to handle these expressions as well.
The transformation for forall quantifiers performs a forall introduction by showing that the expression terminates for an arbitrary choice of quantified variable values.
In the case of existential quantifiers, we obtain the witness and thus perform existential elimination