# Need Help Understanding Protocols and Generics

**URL:** <https://forums.swift.org/t/need-help-understanding-protocols-and-generics/37564>\
**Category:** Using Swift\
**Created:** [June 14, 2020, 12:55pm UTC](https://forums.swift.org/t/need-help-understanding-protocols-and-generics/37564 "2020-06-14T12:55:56Z")\
**Posts on this page:** 1\
**Showing post:** 21

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**Author:** ![xwu](https://avatars.discourse-cdn.com/v4/letter/x/b487fb/32.png) [@xwu](https://forums.swift.org/u/xwu)\
**Post date:** [June 15, 2020, 4:55pm UTC](https://forums.swift.org/t/need-help-understanding-protocols-and-generics/37564/21 "2020-06-15T16:55:43Z")

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> [@Nevin](#):
>
> ```swift
> class C: P {}
> class D: C, Q { var id: String { "D" } }
> 
> ```

This implicates bug [SR-103](https://bugs.swift.org/browse/SR-103). See also [this thread](https://forums.swift.org/t/default-protocol-implementation-inheritance-behaviour-the-current-situation-and-what-if-anything-should-be-done-about-it/28049).

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