Sema: Map raw type into context before checking conditional conformance

Author: slavapestov

lib/Sema/TypeCheckProtocol.cpp

@@ -5674,6 +5674,9 @@ void swift::diagnoseConformanceFailure(Type T,
 
       // If the reason is that the raw type does not conform to
       // Equatable, say so.
+      //
+      // Map it into context since we want to check conditional requirements.
+      rawType = enumDecl->mapTypeIntoContext(rawType);
       if (!TypeChecker::conformsToKnownProtocol(
               rawType, KnownProtocolKind::Equatable, DC->getParentModule())) {
         SourceLoc loc = enumDecl->getInherited().getStartLoc();