No Fallthrough Only
ID |
swift.no_fallthrough_only |
Severity |
low |
Remediation Complexity |
trivial |
Remediation Risk |
low |
Remediation Effort |
low |
Resource |
Reliability |
Language |
Swift |
Tags |
reliability, suspicious-code |
Description
Reports a switch case whose body is exactly one fallthrough
statement. The case has no work of its own and behaves identically to
extending the next case label’s pattern list.
switch state {
case .loading:
fallthrough // FLAW
case .ready:
refresh()
}Rationale
A case that does nothing but fall through is almost always either a
typo (the case body was forgotten) or a translation artefact from a
C-style switch. The equivalent Swift idiom is a single case label
with multiple patterns — that makes the "same body for both" intent
explicit, prevents accidental drift if .ready later changes
behaviour, and avoids relying on the order of cases.
Remediation
Collapse the patterns into a single case label:
switch state {
case .loading, .ready:
refresh()
}If the intent was actually to run additional code before falling
through, add a real statement before the fallthrough — the rule
only fires when the case body is a lone fallthrough.