feat: add detectors for unused events and unused modifiers#2970
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ep0chzer0 wants to merge 2 commits intocrytic:masterfrom
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feat: add detectors for unused events and unused modifiers#2970ep0chzer0 wants to merge 2 commits intocrytic:masterfrom
ep0chzer0 wants to merge 2 commits intocrytic:masterfrom
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Add two new informational detectors to identify dead code: - `unused-events`: Detects events declared but never emitted anywhere in the compilation unit. Skips interface contracts and dependencies. - `unused-modifiers`: Detects modifiers declared but never applied to any function. Handles inheritance correctly by skipping virtual modifiers that are overridden in child contracts. Both detectors include comprehensive test contracts covering: - Basic unused/used elements - Inheritance chains (base events emitted by children) - Virtual modifier override patterns - Interface event declarations Closes crytic#2782 (partial - errors covered by crytic#2902)
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Summary
Adds two new informational detectors for comprehensive dead code detection, addressing #2782:
unused-events— Detects events declared but never emitted anywhere in the compilation unitunused-modifiers— Detects modifiers declared but never applied to any functionTogether with the unused custom errors detector in #2902, this completes the dead code detection coverage for errors, events, and modifiers requested in #2782.
Detection Logic
Unused Events
EventCallIR operations to build a set of emitted event namesUnused Modifiers
function.modifiersacross all derived contractsoverridden_byand manual inheritance chain check)Test Coverage
Unused Events (6 contracts):
NeverEmitted,AlsoNeverEmitted,OrphanEvent(in base contract)Unused Modifiers (5 contracts):
neverUsed,alsoNeverUsed,unusedVirtualMod(virtual but not overridden)Files Changed
slither/detectors/functions/unused_events.py— New detectorslither/detectors/functions/unused_modifiers.py— New detectorslither/detectors/all_detectors.py— Register both detectorstests/e2e/detectors/test_detectors.py— Add test entriestests/e2e/detectors/test_data/unused-events/— Test contracts and artifactstests/e2e/detectors/test_data/unused-modifiers/— Test contracts and artifactstests/e2e/detectors/snapshots/— Expected output snapshotsAll 383 detector tests pass (381 existing + 2 new).
Closes #2782 (events + modifiers; errors covered by #2902)