swift

223944b5 - RequirementMachine: Don't diagnose trivial circularity 'protocol P : P' as redundant

RequirementMachine: Don't diagnose trivial circularity 'protocol P : P' as redundant Every protocol gets an 'identity conformance' rule [P].[P] => [P]. A trivially-stated circularity is always redundant because of this rule, and we diagnose circular inheritance elsewhere as a hard error, so just add a special case to skip adding such a rule here to avoid the useless warning on top of the existing error.