30 lines
905 B
Ruby
30 lines
905 B
Ruby
methods {
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balanceOf(address, uint256) returns uint256 envfree
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isApprovedForAll(address,address) returns bool envfree
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}
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/// If a method call reduces account balances, the caller must be either the
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/// holder of the account or approved to act on the holder's behalf.
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rule onlyHolderOrApprovedCanReduceBalance {
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address holder; uint256 token; uint256 amount;
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uint256 balanceBefore = balanceOf(holder, token);
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method f; env e; calldataarg args;
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f(e, args);
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uint256 balanceAfter = balanceOf(holder, token);
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assert balanceAfter < balanceBefore => e.msg.sender == holder || isApprovedForAll(holder, e.msg.sender),
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"An account balance may only be reduced by the holder or a holder-approved agent";
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}
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/// This rule should always fail.
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rule sanity {
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method f; env e; calldataarg args;
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f(e, args);
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assert false,
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"This rule should always fail";
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}
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