diff --git a/lib/selectors/user-selectors.js b/lib/selectors/user-selectors.js
--- a/lib/selectors/user-selectors.js
+++ b/lib/selectors/user-selectors.js
@@ -16,10 +16,7 @@
 import type { BaseAppState } from '../types/redux-types.js';
 import { userRelationshipStatus } from '../types/relationship-types.js';
 import { threadTypes } from '../types/thread-types-enum.js';
-import type {
-  LegacyRawThreadInfo,
-  RawThreadInfos,
-} from '../types/thread-types.js';
+import type { RawThreadInfos } from '../types/thread-types.js';
 import type {
   UserInfos,
   RelativeUserInfo,
@@ -54,55 +51,35 @@
   return relativeUserInfos;
 }
 
-type ExtractArrayParam = <T>(arr: $ReadOnlyArray<T>) => T;
-
-function getRelativeMemberInfos<TI: RawThreadInfo | LegacyRawThreadInfo>(
-  threadInfo: ?TI,
+function getRelativeMemberInfos(
+  threadInfo: ?RawThreadInfo,
   currentUserID: ?string,
   userInfos: UserInfos,
-): $ReadOnlyArray<
-  $ReadOnly<{
-    ...$Call<ExtractArrayParam, $PropertyType<TI, 'members'>>,
-    +username: ?string,
-    +isViewer: boolean,
-  }>,
-> {
-  const relativeMemberInfos: Array<
-    $ReadOnly<{
-      ...$Call<ExtractArrayParam, $PropertyType<TI, 'members'>>,
-      +username: ?string,
-      +isViewer: boolean,
-    }>,
-  > = [];
+): $ReadOnlyArray<RelativeMemberInfo> {
+  const relativeMemberInfos: RelativeMemberInfo[] = [];
   if (!threadInfo) {
     return relativeMemberInfos;
   }
   const memberInfos = threadInfo.members;
-  for (const memberInfoInput of memberInfos) {
-    const memberInfo: $Call<
-      ExtractArrayParam,
-      $PropertyType<TI, 'members'>,
-    > = memberInfoInput;
+  for (const memberInfo of memberInfos) {
     if (!memberInfo.role) {
       continue;
     }
-    const username: ?string = userInfos[memberInfo.id]
+    const username = userInfos[memberInfo.id]
       ? userInfos[memberInfo.id].username
       : null;
-    const isViewer: boolean = memberInfo.id === currentUserID;
-    const relativeMemberInfo: $ReadOnly<{
-      ...$Call<ExtractArrayParam, $PropertyType<TI, 'members'>>,
-      +username: ?string,
-      +isViewer: boolean,
-    }> = {
-      ...memberInfo,
-      username,
-      isViewer,
-    };
-    if (isViewer) {
-      relativeMemberInfos.unshift(relativeMemberInfo);
+    if (memberInfo.id === currentUserID) {
+      relativeMemberInfos.unshift({
+        ...memberInfo,
+        username,
+        isViewer: true,
+      });
     } else {
-      relativeMemberInfos.push(relativeMemberInfo);
+      relativeMemberInfos.push({
+        ...memberInfo,
+        username,
+        isViewer: false,
+      });
     }
   }
   return relativeMemberInfos;