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Dan RobinsonParadigm
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Dan Robinson
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for-init tuple variable declaration returns Panic(0)

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Author
@onlybejita
Points
0
Verdict
—
Resolution
—
Submitted
Aug 1, 2026, 03:41 PM
Reviewed
Aug 9, 2026, 07:02 PM

Source

// SPDX-License-Identifier: MIT
pragma solidity 0.8.35;

/* ===ARENA-MANIFEST===
{
  "deploy": { "contract": "T", "args": [], "value": 0 },
  "entry":  { "function": "f", "args": [] },
  "note":   "SOUNDNESS_GAP: a TUPLE variable declaration in a for-loop initializer. solc 0.8.35 accepts it and the loop sums 0..9, returning 45; solidity-lean runs and reverts Panic(0). The same tuple declaration in a loop BODY, an if branch, an unchecked block or a bare nested block is handled correctly, so the gap is specific to the for-initializer slot."
}
===END-ARENA-MANIFEST=== */

contract T {
    function f() external pure returns (uint256) {
        uint256 acc;
        for ((uint256 i, uint256 j) = (0, 10); i < j; i++) {
            acc += i;
        }
        return acc;
    }
}