# Redundant conformance error using protocol composition

**URL:** <https://forums.swift.org/t/redundant-conformance-error-using-protocol-composition/21415>\
**Category:** Compiler\
**Tags:** swift5\
**Created:** [March 9, 2019, 2:58pm UTC](https://forums.swift.org/t/redundant-conformance-error-using-protocol-composition/21415 "2019-03-09T14:58:04Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![Douglas\_Gregor](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/douglas_gregor/32/1362_2.png) [@Douglas\_Gregor](https://forums.swift.org/u/Douglas_Gregor)\
**Post date:** [July 18, 2019, 4:16pm UTC](https://forums.swift.org/t/redundant-conformance-error-using-protocol-composition/21415/4 "2019-07-18T16:16:37Z")

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> [@stunba](#):
>
> It's compilation errors. I tried to set everything like "treat warning like errors" to false but it didn't help.  
> It tried it on swift 5.0 snapshots.

We just managed to fix this with [[5.1] [Name lookup] Deduplicate nominal declarations found via resolveTypeDeclsToNominal by DougGregor · Pull Request #26177 · apple/swift · GitHub](https://github.com/apple/swift/pull/26177).

Doug

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