mcp-server-semgrep/semgrep-rules/solidity/performance/array-length-outside-loop.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
  - id: array-length-outside-loop
    message: Caching the array length outside a loop saves reading it on each
      iteration, as long as the array's length is not changed during the loop.
    metadata:
      references:
        - https://github.com/byterocket/c4-common-issues/blob/main/0-Gas-Optimizations.md/#g002---cache-array-length-outside-of-loop
      category: performance
      technology:
        - solidity
    patterns:
      - pattern-either:
          - pattern-inside: |
              for (...) {
                ...
              }
          - pattern-inside: |
              while (...) {
                ...
              }
      - pattern-not-inside: |
          function $F(..., $TYPE calldata $VAR, ...) {
            ...
          }
      - pattern-not-inside: |
          function $F(...) {
            ...
            $TYPE[...] storage $VAR;
            ...
          }
      - pattern-not-inside: |
          function $F(...) {
            ...
            $TYPE[...] storage $VAR = ...;
            ...
          }
      - pattern: |
          $VAR.length
    languages:
      - solidity
    severity: INFO