diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -1733,11 +1733,11 @@
 }
 
 function patchThreadInfoToIncludeMentionedMembersOfParent(
-  threadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
-  parentThreadInfo: ThreadInfo | MinimallyEncodedThreadInfo,
+  threadInfo: ThreadInfo,
+  parentThreadInfo: ThreadInfo,
   messageText: string,
   viewerID: string,
-): ThreadInfo | MinimallyEncodedThreadInfo {
+): ThreadInfo {
   const members: UserIDAndUsername[] = threadInfo.members
     .map(({ id, username }) => (username ? { id, username } : null))
     .filter(Boolean);
diff --git a/lib/utils/entity-helpers.js b/lib/utils/entity-helpers.js
--- a/lib/utils/entity-helpers.js
+++ b/lib/utils/entity-helpers.js
@@ -93,7 +93,7 @@
 function useResolvedThreadInfosObj(
   threadInfosObj: { +[id: string]: ThreadInfo },
   options?: ?UseENSNamesOptions,
-): { +[id: string]: ResolvedThreadInfo } {
+): { +[id: string]: ResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo } {
   const threadInfosArray = React.useMemo(
     () => values(threadInfosObj),
     [threadInfosObj],
diff --git a/web/input/input-state-container.react.js b/web/input/input-state-container.react.js
--- a/web/input/input-state-container.react.js
+++ b/web/input/input-state-container.react.js
@@ -1284,16 +1284,10 @@
       time: Date.now(),
     };
 
-    // Branching to appease `flow`.
-    const newThreadInfo = threadInfo.minimallyEncoded
-      ? {
-          ...threadInfo,
-          id: newThreadID,
-        }
-      : {
-          ...threadInfo,
-          id: newThreadID,
-        };
+    const newThreadInfo = {
+      ...threadInfo,
+      id: newThreadID,
+    };
     this.props.dispatchActionPromise(
       sendTextMessageActionTypes,
       this.sendTextMessageAction(