refactor(types): typed send helpers replace 16 as any casts (#210)

- sendRoomMessage (composer's fire-and-forget sends: text, location, voice,
  files, GIFs) and sendRoomEvent (polls, poll responses/ends, forwards,
  reactions, edits) in utils/room.ts carry the one cast each needs
  (`keyof TimelineEvents` / `RoomMessageEventContent`, no `any`).
- sendRoomMessage also swallows the rejected promise: a failed send already
  shows on the local echo (Failed to send + Retry, or the consent prompt), so
  it no longer surfaces as an unhandled error in the console.
- getAccountData narrows to `keyof AccountDataEvents`; ForwardMessageDialog's
  guard now narrows `contentToSend` itself (same behaviour).
- `as any` 39 → 23; eslint warnings 46 → 36, ratchet tightened to 36.

Verified in Chromium on a local Synapse: a text message, a quick reaction and
an edit all reach the server with the right content; a consent-blocked send
no longer logs an unhandled MatrixError. 1219 unit tests pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

package.json

@@ -12,7 +12,7 @@
     "build": "vite build",
     "preview": "vite preview",
     "lint": "npm run check:eslint && npm run check:prettier",
-    "check:eslint": "eslint src/* --max-warnings 46",
+    "check:eslint": "eslint src/* --max-warnings 36",
     "check:prettier": "prettier --check .",
     "fix:prettier": "prettier --write .",
     "typecheck": "tsc --noEmit",

src/app/components/message/content/PollContent.tsx

@@ -1,10 +1,9 @@
-/* eslint-disable @typescript-eslint/no-explicit-any */
 import React, { KeyboardEvent, useCallback, useEffect, useMemo, useState } from 'react';
 import { Box, Chip, color, config, Icon, Icons, Text, toRem } from 'folds';
 import { RelationsEvent } from 'matrix-js-sdk/lib/models/relations';
 import { MatrixEvent, Room, RoomEvent, PollEvent } from 'matrix-js-sdk';
 import { useMatrixClient } from '../../../hooks/useMatrixClient';
-import { getMemberName } from '../../../utils/room';
+import { getMemberName, sendRoomEvent } from '../../../utils/room';
 import {
   ParsedPoll,
   PollResponse,
@@ -220,7 +219,7 @@ export function PollContent({
     setPending(next);
     // Send the STABLE m.poll.response (matches Lotus's stable m.poll.start; the reader
     // accepts both namespaces).
-    mx.sendEvent(roomId, 'm.poll.response' as any, {
+    sendRoomEvent(mx, roomId, null, 'm.poll.response', {
       'm.relates_to': { rel_type: 'm.reference', event_id: eventId },
       'm.selections': Array.from(next),
     }).catch(() => setPending(null));
@@ -229,7 +228,7 @@ export function PollContent({
   const handleEndPoll = () => {
     if (!roomId || !eventId || ending) return;
     setEnding(true);
-    mx.sendEvent(roomId, 'm.poll.end' as any, {
+    sendRoomEvent(mx, roomId, null, 'm.poll.end', {
       'm.relates_to': { rel_type: 'm.reference', event_id: eventId },
       'm.poll.end': {},
       'm.text': 'The poll has ended.',

src/app/features/room/PollCreator.tsx

@@ -21,6 +21,7 @@ import { Room } from 'matrix-js-sdk';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { stopPropagation } from '../../utils/keyboard';
 import { useModalStyle } from '../../hooks/useModalStyle';
+import { sendRoomEvent } from '../../utils/room';
 
 interface PollCreatorProps {
   roomId: string;
@@ -89,7 +90,7 @@ export function PollCreator({ roomId, threadRootId, onClose }: PollCreatorProps)
       );
       // Pass the thread id explicitly (like the sticker path in RoomInput); the
       // legacy 3-arg form always resolves to the main timeline.
-      await mx.sendEvent(roomId, threadRootId ?? null, 'm.poll.start' as any, {
+      await sendRoomEvent(mx, roomId, threadRootId ?? null, 'm.poll.start', {
         'm.poll': {
           question: { 'm.text': trimmedQuestion },
           answers: filledOptions.map((o, i) => ({ 'm.id': `${i}`, 'm.text': o })),

src/app/features/room/RoomInput.tsx

@@ -112,7 +112,12 @@ import {
   getImageMsgContent,
   getVideoMsgContent,
 } from './msgContent';
-import { getMemberName, getMentionContent, trimReplyFromBody } from '../../utils/room';
+import {
+  getMemberName,
+  getMentionContent,
+  sendRoomMessage,
+  trimReplyFromBody,
+} from '../../utils/room';
 import { CommandAutocomplete } from './CommandAutocomplete';
 import {
   Command,
@@ -324,7 +329,7 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
           // MSC3488 extensible location: send the geo_uri (legacy) alongside the
           // m.location/m.asset/m.ts blocks so Element and other clients render a
           // proper "shared location" pin instead of falling back to plain text.
-          mx.sendMessage(roomId, threadRootId ?? null, {
+          sendRoomMessage(mx, roomId, threadRootId ?? null, {
             msgtype: 'm.location',
             body: `Shared a location: ${geoUri}`,
             geo_uri: geoUri,
@@ -332,7 +337,7 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             'org.matrix.msc3488.asset': { type: 'm.self' },
             'org.matrix.msc3488.ts': ts,
             'm.ts': ts,
-          } as any);
+          });
         },
         (err) => {
           setLocating(false);
@@ -363,19 +368,19 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
         if (room.hasEncryptionStateEvent()) {
           const { encInfo, file: encBlob } = await encryptFile(blob);
           const uploadResult = await mx.uploadContent(encBlob);
-          mx.sendMessage(roomId, threadRootId ?? null, {
+          sendRoomMessage(mx, roomId, threadRootId ?? null, {
             ...baseContent,
             file: { ...encInfo, url: uploadResult.content_uri },
-          } as any);
+          });
         } else {
           const uploadResult = await mx.uploadContent(blob, {
             name: 'voice-message.ogg',
             type: mimeType,
           });
-          mx.sendMessage(roomId, threadRootId ?? null, {
+          sendRoomMessage(mx, roomId, threadRootId ?? null, {
             ...baseContent,
             url: uploadResult.content_uri,
-          } as any);
+          });
         }
       },
       [mx, room, roomId, threadRootId],
@@ -625,7 +630,7 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
         });
         handleCancelUpload(uploads);
         const contents = fulfilledPromiseSettledResult(await Promise.allSettled(contentsPromises));
-        contents.forEach((content) => mx.sendMessage(roomId, threadRootId ?? null, content as any));
+        contents.forEach((content) => sendRoomMessage(mx, roomId, threadRootId ?? null, content));
       },
       [mx, roomId, threadRootId, selectedFiles, handleCancelUpload],
     );
@@ -732,7 +737,7 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
           content['m.relates_to'].is_falling_back = false;
         }
       }
-      mx.sendMessage(roomId, threadRootId ?? null, content as any);
+      sendRoomMessage(mx, roomId, threadRootId ?? null, content);
       resetEditor(editor);
       resetEditorHistory(editor);
       setCharCount(0);
@@ -955,10 +960,10 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             const uploadRes = await mx.uploadContent(encBlob);
             const mxcUrl = (uploadRes as { content_uri: string }).content_uri;
             if (!mxcUrl) return;
-            mx.sendMessage(roomId, threadRootId ?? null, {
+            sendRoomMessage(mx, roomId, threadRootId ?? null, {
               ...baseContent,
               file: { ...encInfo, url: mxcUrl },
-            } as any);
+            });
           } else {
             const uploadRes = await mx.uploadContent(gifFile, {
               type: 'image/gif',
@@ -967,10 +972,10 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             });
             const mxcUrl = (uploadRes as { content_uri: string }).content_uri;
             if (!mxcUrl) return;
-            mx.sendMessage(roomId, threadRootId ?? null, {
+            sendRoomMessage(mx, roomId, threadRootId ?? null, {
               ...baseContent,
               url: mxcUrl,
-            } as any);
+            });
           }
         } catch (e) {
           console.error('GIF send failed:', e instanceof Error ? e.message : 'unknown error');

src/app/features/room/RoomTimeline.tsx

@@ -89,6 +89,7 @@ import {
   getReactionContent,
   isMembershipChanged,
   reactionOrEditEvent,
+  sendRoomEvent,
 } from '../../utils/room';
 import { getLastEditDiff } from '../../utils/editDiff';
 import { tick } from '../../utils/haptics';
@@ -1160,9 +1161,11 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
         shortcode ||
         (reactions.find(eventWithShortcode)?.getContent().shortcode as string | undefined);
       tick('reaction', hapticFeedback);
-      mx.sendEvent(
+      sendRoomEvent(
+        mx,
         room.roomId,
-        MessageEvent.Reaction as any,
+        null,
+        MessageEvent.Reaction,
         getReactionContent(targetEventId, key, rShortcode),
       );
     },

src/app/features/room/message/ForwardMessageDialog.tsx

@@ -36,7 +36,12 @@ import { mxcUrlToHttp } from '../../../utils/matrix';
 import { RoomAvatar, RoomIcon } from '../../../components/room-avatar';
 import { UserAvatar } from '../../../components/user-avatar';
 import { ThumbnailContent } from '../../../components/message/content/ThumbnailContent';
-import { getMemberAvatarMxc, getMemberName, trimReplyFromBody } from '../../../utils/room';
+import {
+  getMemberAvatarMxc,
+  getMemberName,
+  sendRoomEvent,
+  trimReplyFromBody,
+} from '../../../utils/room';
 import { nameInitials } from '../../../utils/common';
 import {
   recentForwardTargetsAtom,
@@ -349,12 +354,12 @@ export function ForwardMessageDialog({ mEvent, onClose }: Props) {
       // content; unencrypted ones get the plaintext version, or fail outright if
       // that couldn't be built — never fall back to sending the encrypted `file`.
       const contentToSend = fwdContent.file && !destEncrypted ? plaintextContent : fwdContent;
-      if (fwdContent.file && !destEncrypted && !contentToSend) {
+      // Only undefined when a plaintext copy was needed and couldn't be built.
+      if (!contentToSend) {
         return Promise.reject(new Error(plaintextContentError));
       }
-      // threadId-aware overload (P3-8): explicit null = send to the main timeline.
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      const sendForward = () => mx.sendEvent(id, null, mEvent.getType() as any, contentToSend);
+      // Explicit null thread = send to the main timeline.
+      const sendForward = () => sendRoomEvent(mx, id, null, mEvent.getType(), contentToSend);
       // Send the optional comment first so it reads as a note above the
       // forwarded content. The room counts as failed if either send rejects.
       // Track rooms whose comment already landed so a retry (after the FORWARD

src/app/features/room/message/MessageEditor.tsx

@@ -21,7 +21,15 @@ import {
 } from 'folds';
 import { Editor, Transforms } from 'slate';
 import { ReactEditor } from 'slate-react';
-import { IContent, IMentions, MatrixEvent, MsgType, RelationType, Room } from 'matrix-js-sdk';
+import {
+  EventType,
+  IContent,
+  IMentions,
+  MatrixEvent,
+  MsgType,
+  RelationType,
+  Room,
+} from 'matrix-js-sdk';
 import { isKeyHotkey } from 'is-hotkey';
 import {
   AUTOCOMPLETE_PREFIXES,
@@ -55,6 +63,7 @@ import {
   getEditedEvent,
   getMemberName,
   getMentionContent,
+  sendRoomEvent,
   trimReplyFromFormattedBody,
 } from '../../../utils/room';
 import { mobileOrTablet } from '../../../utils/user-agent';
@@ -192,8 +201,7 @@ export const MessageEditor = as<'div', MessageEditorProps>(
               rel_type: RelationType.Replace,
             },
           };
-          // eslint-disable-next-line @typescript-eslint/no-explicit-any
-          return mx.sendMessage(roomId, content as any);
+          return sendRoomEvent(mx, roomId, null, EventType.RoomMessage, content);
         }
 
         const [prevBody, prevCustomHtml, prevMentions] = getPrevBodyAndFormattedBody();
@@ -241,8 +249,7 @@ export const MessageEditor = as<'div', MessageEditorProps>(
           },
         };
 
-        // eslint-disable-next-line @typescript-eslint/no-explicit-any
-        return mx.sendMessage(roomId, content as any);
+        return sendRoomEvent(mx, roomId, null, EventType.RoomMessage, content);
       }, [
         stripTracking,
         mx,

src/app/features/room/thread/ThreadTimeline.tsx

@@ -67,6 +67,7 @@ import {
   getMemberName,
   getReactionContent,
   reactionOrEditEvent,
+  sendRoomEvent,
 } from '../../../utils/room';
 import { useSetting } from '../../../state/hooks/settings';
 import { MessageLayout, settingsAtom } from '../../../state/settings';
@@ -576,12 +577,12 @@ export function ThreadTimeline({ room, thread, editor }: ThreadTimelineProps) {
         shortcode ||
         (reactions.find(eventWithShortcode)?.getContent().shortcode as string | undefined);
       tick('reaction', hapticFeedback);
-      mx.sendEvent(
+      sendRoomEvent(
+        mx,
         room.roomId,
         // A reaction on the root is a main-timeline event, not a thread reply.
         isRoot ? null : thread.id,
-        // eslint-disable-next-line @typescript-eslint/no-explicit-any
-        MessageEvent.Reaction as any,
+        MessageEvent.Reaction,
         getReactionContent(targetEventId, key, rShortcode),
       );
     },

src/app/utils/room.ts

@@ -1,9 +1,11 @@
 import { IconName, IconSrc } from 'folds';
 
 import {
+  AccountDataEvents,
   EventTimeline,
   EventTimelineSet,
   EventType,
+  IContent,
   IMentions,
   IPowerLevelsContent,
   IPushRule,
@@ -17,8 +19,10 @@ import {
   RelationType,
   Room,
   RoomMember,
+  TimelineEvents,
 } from 'matrix-js-sdk';
 import { CryptoBackend } from 'matrix-js-sdk/lib/common-crypto/CryptoBackend';
+import type { RoomMessageEventContent } from 'matrix-js-sdk/lib/@types/events';
 import { AccountDataEvent } from '../../types/matrix/accountData';
 import {
   IRoomCreateContent,
@@ -62,10 +66,43 @@ export function sendStateEvent<T extends object>(
   return mx.sendStateEvent(roomId, eventType as any, content, stateKey);
 }
 
+// Typed message send for the composer's fire-and-forget sends. The SDK's
+// `sendMessage` wants its `RoomMessageEventContent` union, which the composer's
+// extensible content (MSC3488 location, MSC3245 voice, `m.mentions`, encrypted
+// `file`) doesn't narrow to; the single cast lives here. A failed send already
+// shows on the local echo ("Failed to send" with Retry, or the consent prompt),
+// so the rejection is swallowed rather than surfacing as an unhandled error.
+export function sendRoomMessage(
+  mx: MatrixClient,
+  roomId: string,
+  threadId: string | null,
+  content: IContent,
+): void {
+  mx.sendMessage(roomId, threadId, content as RoomMessageEventContent).catch(() => undefined);
+}
+
+// Typed send for events whose type isn't one of the SDK's typed timeline events
+// (MSC3381 polls, forwarded arbitrary types, the fork's reaction enum) or whose
+// content is extensible. Keeps the one cast out of every call site.
+export function sendRoomEvent(
+  mx: MatrixClient,
+  roomId: string,
+  threadId: string | null,
+  eventType: string,
+  content: IContent,
+): Promise<ISendEventResponse> {
+  return mx.sendEvent(
+    roomId,
+    threadId,
+    eventType as keyof TimelineEvents,
+    content as TimelineEvents[keyof TimelineEvents],
+  );
+}
+
 export const getAccountData = (
   mx: MatrixClient,
   eventType: AccountDataEvent | string,
-): MatrixEvent | undefined => mx.getAccountData(eventType as any);
+): MatrixEvent | undefined => mx.getAccountData(eventType as keyof AccountDataEvents);
 
 export const getMDirects = (mDirectEvent: MatrixEvent): Set<string> => {
   const roomIds = new Set<string>();