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Version: 0.9

SuspiciousMessageMode

Severity: Low—Medium | Category: Security

Detects suspicious usage of the mode field in SendParameters struct instances.

Why is it bad?​

Incorrect usage of the mode field in SendParameters can lead to unintended behavior when sending messages, such as incorrect flags being set, which can cause security vulnerabilities or unexpected contract behavior.

What it checks:

  • Ensures that the mode expression only uses the bitwise OR operator |.
  • Warns if integer literals are used instead of symbolic constants.
  • Warns if the same flag is used multiple times in the mode expression.

Example​

// Suspicious usage:
send(SendParameters{
    to: recipient,
    value: amount,
    mode: SendRemainingBalance | SendRemainingBalance // Bad: Duplicate flag
});

// Correct usage:
send(SendParameters{
    to: recipient,
    value: amount,
    mode: SendRemainingBalance | SendDestroyIfZero // Ok
});