Type Change Consequences

Consequence

Type change consequences refer to the adverse effects that arise when the data type of a variable within a smart contract’s storage is altered, particularly during an upgrade. Changing a variable from, for instance, a uint256 to a bytes32 or a smaller integer type can lead to misinterpretation of existing data. The EVM interprets storage slots based on their declared types, so a mismatch can cause data corruption, truncation, or incorrect value reads. This is a critical structural vulnerability.