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rust-doctor · Performance

large-enum-variant

Flags enums where variants have significantly different sizes (>3x field count disparity). The enum's size equals its largest variant, wasting memory for smaller variants.

Severity
warning
Confidence
medium
Analyzer
syn-ast
Default policy
Enabled

Tags

  • heuristic
  • performance

Framework requirements

No framework requirement.

Limitations

  • The rule counts fields rather than calculating each variant's concrete byte layout.

Remediation

Box the large variant's data: `LargeVariant(Box<LargeData>)`.

Fix capability: guidance