False-positive using protocols and nested structs

[meyers-oai]

Describe the bug
I've come across a false positive in my dependency injection setup. I'm not sure why, but I've simplified the repro case (attached) to 50 lines.
Didn't seem like this is related to any known bugs or open issues.

Reproduction
test-periphery.zip

Scanning will report the following 3 false-positives:

test-periphery/test/testApp.swift:21:8: warning: Struct 'DefaultCache' is unused
test-periphery/test/testApp.swift:51:7: warning: Property 'cache' is unused
test-periphery/test/testApp.swift:59:7: warning: Property 'cache' is unused

Environment
3.3.0
swift-driver version: 1.127.14.1 Apple Swift version 6.2.1 (swiftlang-6.2.1.4.8 clang-1700.4.4.1)
Target: arm64-apple-macosx26.0
Xcode 26.1.1
Build version 17B100

[meyers-oai]

Thank you @ileitch!