diff --git a/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts b/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts
index 5fc2a3cec3..6c69a80cb1 100644
--- a/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts
+++ b/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts
@@ -5245,7 +5245,15 @@ export class ClassDynamicDispatch {
     if (methodInfo) {
       owner = methodInfo.declarer;
       params = methodInfo.sig.params;
-      result = methodInfo.sig.ret;
+      // An untyped async method's `dyn` result is its promise's payload; the
+      // call answers the promise. An async generator method answers its
+      // generator object, which its signature already returns.
+      result =
+        methodInfo.sig.async === true &&
+        !methodInfo.sig.gen &&
+        methodInfo.sig.ret.kind !== "promise"
+          ? { kind: "promise", inner: methodInfo.sig.ret }
+          : methodInfo.sig.ret;
       callee = `%${owner.def.name}.${method}`;
       virtual = lowerer.overrideBelow(owner, method) || methodInfo.sig.abstract === true;
     } else if (
diff --git a/packages/compiler/src/frontend/lowering/class-prototypes.ts b/packages/compiler/src/frontend/lowering/class-prototypes.ts
index 6c6c7811dd..7b4b58ae36 100644
--- a/packages/compiler/src/frontend/lowering/class-prototypes.ts
+++ b/packages/compiler/src/frontend/lowering/class-prototypes.ts
@@ -189,12 +189,16 @@ export function classPrototypeData(
         continue;
       const compiled = classMethodValue(lowerer, access, info, method, locOf(access));
       if (!compiled) continue;
+      // A method value without a checked-dynamic form (an async method's
+      // promise-returning signature) gets no data slot.
+      const boxedValue = lowerer.coerceToExpected(compiled, DYN);
+      if (boxedValue.type.kind !== "dyn") continue;
       const descriptor: IrExpr = {
         kind: "dynObjLit",
         fields: [
           {
             key: { kind: "strLit", value: "value", type: STRING, loc },
-            value: lowerer.coerceToExpected(compiled, DYN),
+            value: boxedValue,
           },
           {
             key: { kind: "strLit", value: "writable", type: STRING, loc },
diff --git a/packages/compiler/src/frontend/lowering/lower-classes.ts b/packages/compiler/src/frontend/lowering/lower-classes.ts
index 182a73f14e..10927e49b2 100644
--- a/packages/compiler/src/frontend/lowering/lower-classes.ts
+++ b/packages/compiler/src/frontend/lowering/lower-classes.ts
@@ -6723,14 +6723,22 @@ function thunkAsyncSlot(
 ): void {
   if (overridden.sig.async !== true) return;
   const declarer = overridden.declarer;
+  // The slot answers the body's promise: an untyped async method's `dyn`
+  // result is the promise's payload, so the slot's ABI is that promise. An
+  // async generator method's slot keeps its generator object.
+  const ret: IrType =
+    overridden.sig.gen || overridden.sig.ret.kind === "promise"
+      ? overridden.sig.ret
+      : { kind: "promise", inner: overridden.sig.ret };
   declarer.returnAdapters ??= new Map();
   if (!declarer.returnAdapters.has(mName)) {
     declarer.returnAdapters.set(mName, {
       params: [...overridden.sig.params],
-      ret: overridden.sig.ret,
+      ret,
       async: true,
     });
   }
+  overridden.sig.ret = ret;
   delete overridden.sig.async;
 }
 
diff --git a/packages/compiler/src/ir/ir.ts b/packages/compiler/src/ir/ir.ts
index 4c5bbd183f..f71b8de2c2 100644
--- a/packages/compiler/src/ir/ir.ts
+++ b/packages/compiler/src/ir/ir.ts
@@ -4214,6 +4214,10 @@ export function canConvertToDyn(
         (a) =>
           a.kind === "undefinedT" ||
           isJsonSafeType(a, getRecord, getUnion) ||
+          // Composite arms (records holding dyn, Map or Set members) box
+          // through the walker beside the promise arm: a method answering
+          // either its result or a promise of it.
+          canBoxDynComposite(a, getRecord, getUnion, visiting) ||
           isDynTypedRefType(a) ||
           a.kind === "classval" ||
           DYN_HANDLE_KINDS.has(a.kind) ||
diff --git a/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6419-untyped-async-package/main.ts.json b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6419-untyped-async-package/main.ts.json
new file mode 100644
index 0000000000..ab4ee5819a
--- /dev/null
+++ b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6419-untyped-async-package/main.ts.json
@@ -0,0 +1,6 @@
+{
+ "order": [
+  "<repo>/tests/corpus/6419-untyped-async-package/main.ts"
+ ],
+ "diags": []
+}
diff --git a/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6592-promise-armed-method-values/main.ts.json b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6592-promise-armed-method-values/main.ts.json
new file mode 100644
index 0000000000..1fb3f21bc8
--- /dev/null
+++ b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6592-promise-armed-method-values/main.ts.json
@@ -0,0 +1,6 @@
+{
+ "order": [
+  "<repo>/tests/corpus/6592-promise-armed-method-values/main.ts"
+ ],
+ "diags": []
+}
diff --git a/tests/corpus/6419-untyped-async-package/main.ts b/tests/corpus/6419-untyped-async-package/main.ts
new file mode 100644
index 0000000000..9ec10f7c50
--- /dev/null
+++ b/tests/corpus/6419-untyped-async-package/main.ts
@@ -0,0 +1,38 @@
+// Untyped async methods of a package, reached through the package's own
+// untyped callers and prototype reflection, and overridden by a typed
+// subclass. An async generator method called from the package answers its
+// generator object.
+import { Pool, Schema, limiter, listIssues, prototypeNames, validateAll } from "token-pool";
+
+class CountingPool extends Pool {
+  acquired = 0;
+  async acquire(): Promise<void> {
+    await super.acquire();
+    this.acquired++;
+  }
+}
+
+async function main(): Promise<void> {
+  const pool = new CountingPool(1);
+  await pool.acquire();
+  const waiting = pool.acquire();
+  console.log("waiting", pool.nrWaiting());
+  pool.release("t");
+  await waiting;
+  console.log("acquired", pool.acquired, pool.nrWaiting());
+  const base = new Pool(1);
+  console.log("token", await base.acquire());
+  const run = limiter(1);
+  console.log(await Promise.all([run(async () => 1), run(async () => 2)]));
+  const schema = new Schema((value) => typeof value === "number");
+  console.log(await validateAll(schema, [1, "x", 3]));
+  console.log(await listIssues(schema, ["p", 5, "q"]));
+  console.log(await schema.parseAsync(4));
+  try {
+    await schema.parseAsync("y");
+  } catch (e) {
+    console.log("rejected", e instanceof Error ? e.message : String(e));
+  }
+  console.log(prototypeNames());
+}
+main();
diff --git a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts
new file mode 100644
index 0000000000..ed0c82579f
--- /dev/null
+++ b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts
@@ -0,0 +1,17 @@
+export declare class Pool {
+    constructor(size: number);
+    tryAcquire(): any;
+    acquire(): Promise<any>;
+    release(token?: any): void;
+    nrWaiting(): number;
+}
+export declare function limiter(size: number): <T>(work: () => Promise<T>) => Promise<T>;
+export declare class Schema {
+    constructor(check: (value: unknown) => boolean);
+    safeParseAsync(data: unknown): Promise<any>;
+    parseAsync(data: unknown): Promise<any>;
+    issues(values: unknown[]): AsyncGenerator<any>;
+}
+export declare function validateAll(schema: Schema, values: unknown[]): Promise<string>;
+export declare function listIssues(schema: Schema, values: unknown[]): Promise<string>;
+export declare function prototypeNames(): string;
diff --git a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js
new file mode 100644
index 0000000000..04935ff29e
--- /dev/null
+++ b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js
@@ -0,0 +1,123 @@
+"use strict";
+// An untyped token pool and schema in the shape of a semaphore and a
+// validation library: async methods whose results come from storage that
+// passes through untyped helpers.
+Object.defineProperty(exports, "__esModule", { value: true });
+function moveItems(src, srcIndex, dst, dstIndex, len) {
+    for (let j = 0; j < len; ++j) {
+        dst[j + dstIndex] = src[j + srcIndex];
+        src[j + srcIndex] = void 0;
+    }
+}
+class Queue {
+    constructor() {
+        this._length = 0;
+        this.arr = [];
+    }
+    push(item) {
+        if (this._length > 64) moveItems(this.arr, 1, this.arr, 0, this._length - 1);
+        this.arr[this._length] = item;
+        this._length = this._length + 1;
+    }
+    pop() {
+        const length = this._length;
+        if (length === 0) return void 0;
+        const ret = this.arr[length - 1];
+        this.arr[length - 1] = void 0;
+        this._length = length - 1;
+        return ret;
+    }
+    shift() {
+        const length = this._length;
+        if (length === 0) return void 0;
+        const ret = this.arr[0];
+        for (let i = 1; i < length; i++) this.arr[i - 1] = this.arr[i];
+        this.arr[length - 1] = void 0;
+        this._length = length - 1;
+        return ret;
+    }
+    get length() {
+        return this._length;
+    }
+}
+class Pool {
+    constructor(size) {
+        this.free = new Queue();
+        this.waiting = new Queue();
+        for (let i = 0; i < size; i++) this.free.push("token" + i);
+    }
+    tryAcquire() {
+        return this.free.pop();
+    }
+    async acquire() {
+        const token = this.tryAcquire();
+        if (token !== void 0) return token;
+        return new Promise((resolve) => {
+            this.waiting.push(resolve);
+        });
+    }
+    release(token) {
+        const next = this.waiting.shift();
+        if (next) next(token);
+        else this.free.push(token);
+    }
+    nrWaiting() {
+        return this.waiting.length;
+    }
+}
+exports.Pool = Pool;
+function limiter(size) {
+    const pool = new Pool(size);
+    return async function limited(work) {
+        const token = await pool.acquire();
+        try {
+            return await work();
+        } finally {
+            pool.release(token);
+        }
+    };
+}
+exports.limiter = limiter;
+class Schema {
+    constructor(check) {
+        this.check = check;
+        this.results = new Queue();
+    }
+    async safeParseAsync(data) {
+        await null;
+        this.results.push(this.check(data) ? { success: true, data } : { success: false, issue: "invalid " + data });
+        return this.results.pop();
+    }
+    async *issues(values) {
+        for (const value of values) {
+            const result = await this.safeParseAsync(value);
+            if (!result.success) yield result.issue;
+        }
+    }
+    async parseAsync(data) {
+        const result = await this.safeParseAsync(data);
+        if (result.success) return result.data;
+        throw new Error(result.issue);
+    }
+}
+exports.Schema = Schema;
+async function validateAll(schema, values) {
+    const out = [];
+    for (const value of values) {
+        const result = await schema.safeParseAsync(value);
+        out.push(result.success ? "ok " + result.data : result.issue);
+    }
+    return out.join(", ");
+}
+exports.validateAll = validateAll;
+async function listIssues(schema, values) {
+    const out = [];
+    const it = schema.issues(values);
+    for (let step = await it.next(); !step.done; step = await it.next()) out.push(step.value);
+    return out.join(", ");
+}
+exports.listIssues = listIssues;
+function prototypeNames() {
+    return typeof Schema.prototype.parseAsync + " " + typeof Schema.prototype.safeParseAsync;
+}
+exports.prototypeNames = prototypeNames;
diff --git a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/package.json b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/package.json
new file mode 100644
index 0000000000..994de07b2a
--- /dev/null
+++ b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/package.json
@@ -0,0 +1 @@
+{ "name": "token-pool", "version": "1.0.0", "main": "index.js", "types": "index.d.ts" }
diff --git a/tests/corpus/6592-promise-armed-method-values/main.ts b/tests/corpus/6592-promise-armed-method-values/main.ts
new file mode 100644
index 0000000000..379c56ef92
--- /dev/null
+++ b/tests/corpus/6592-promise-armed-method-values/main.ts
@@ -0,0 +1,27 @@
+// Parse steps that answer either a status record or a promise of one keep
+// their method values: reads through untyped code, detached calls, and the
+// per-instance rebinding of the base constructor all see the function.
+import { map, number, object, record, set, stepDetached, stepKinds } from "status-schema";
+async function main(): Promise<void> {
+  const shaped = object({ count: number(), size: number() });
+  const counts = record(number());
+  const byName = map(number());
+  const seen = set(number());
+  console.log(stepKinds(shaped), "|", stepKinds(counts), "|", stepKinds(byName), "|", stepKinds(seen));
+  console.log(shaped.safeParse({ count: 1, size: 2 }).success, shaped.safeParse({ count: "x", size: 2 }).success);
+  console.log(JSON.stringify(shaped.parse({ count: 3, size: 4 })));
+  console.log(JSON.stringify(await shaped.parseAsync({ count: 5, size: 6 })), (await shaped.spa(7)).success);
+  console.log(counts.safeParse({ a: 1, b: 2 }).success, (await counts.safeParseAsync({ a: "x" })).success);
+  console.log(byName.safeParse(new Map([["a", 1]])).success, (await byName.safeParseAsync(new Map([["b", "x"]]))).success);
+  console.log(seen.safeParse(new Set([1, 2])).success, (await seen.spa(new Set([3]))).success);
+  console.log(await stepDetached(shaped, { count: 1, size: 1 }), "|", await stepDetached(counts, { a: "x" }));
+  console.log(await stepDetached(byName, new Map([["c", 2]])), "|", await stepDetached(seen, [1]));
+  try {
+    await counts.parseAsync(null);
+  } catch (e) {
+    console.log("rejected", e instanceof Error ? e.message : String(e));
+  }
+  const nested = object({ inner: record(number()), tags: set(number()) });
+  console.log(JSON.stringify(await nested.parseAsync({ inner: { q: 1 }, tags: new Set([1]) })));
+}
+main();
diff --git a/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/index.d.ts b/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/index.d.ts
new file mode 100644
index 0000000000..6607bf0c7e
--- /dev/null
+++ b/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/index.d.ts
@@ -0,0 +1,18 @@
+export interface SafeResult {
+    success: boolean;
+    data?: unknown;
+}
+export declare class Schema {
+    safeParse(data: unknown): SafeResult;
+    parse(data: unknown): unknown;
+    safeParseAsync(data: unknown): Promise<SafeResult>;
+    spa(data: unknown): Promise<SafeResult>;
+    parseAsync(data: unknown): Promise<unknown>;
+}
+export declare function number(): Schema;
+export declare function object(shape: { [key: string]: Schema }): Schema;
+export declare function record(valueType: Schema): Schema;
+export declare function map(valueType: Schema): Schema;
+export declare function set(valueType: Schema): Schema;
+export declare function stepKinds(schema: Schema): string;
+export declare function stepDetached(schema: Schema, data: unknown): Promise<string>;
diff --git a/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/index.js b/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/index.js
new file mode 100644
index 0000000000..4fb5ae4600
--- /dev/null
+++ b/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/index.js
@@ -0,0 +1,118 @@
+// A schema hierarchy in the shape of a validation library's: each parse
+// step answers a status record or, in async mode, a promise of one built
+// by a static async merge helper. The base constructor rebinds its
+// methods per instance, async ones included.
+export const INVALID = Object.freeze({ status: "aborted" });
+export class Status {
+    static async mergeAsync(pairs) {
+        const settled = [];
+        for (const pair of pairs) {
+            settled.push({ key: pair.key, value: await pair.value });
+        }
+        return Status.mergeSync(settled);
+    }
+    static mergeSync(pairs) {
+        const value = {};
+        for (const pair of pairs) {
+            if (pair.value.status === "aborted") return INVALID;
+            value[pair.key] = pair.value.value;
+        }
+        return { status: "valid", value };
+    }
+}
+export class Schema {
+    constructor(def) {
+        this.spa = this.safeParseAsync;
+        this._def = def;
+        this.parse = this.parse.bind(this);
+        this.safeParse = this.safeParse.bind(this);
+        this.parseAsync = this.parseAsync.bind(this);
+        this.safeParseAsync = this.safeParseAsync.bind(this);
+        this.spa = this.spa.bind(this);
+    }
+    safeParse(data) {
+        const result = this._parse({ data, async: false });
+        if (result instanceof Promise) throw new Error("async parse step in safeParse");
+        return result.status === "valid" ? { success: true, data: result.value } : { success: false };
+    }
+    parse(data) {
+        const result = this.safeParse(data);
+        if (result.success) return result.data;
+        throw new Error(this._def.name + ": invalid input");
+    }
+    async safeParseAsync(data) {
+        const result = await this._parse({ data, async: true });
+        return result.status === "valid" ? { success: true, data: result.value } : { success: false };
+    }
+    async parseAsync(data) {
+        const result = await this.safeParseAsync(data);
+        if (result.success) return result.data;
+        throw new Error(this._def.name + ": invalid input");
+    }
+}
+export class NumberSchema extends Schema {
+    _parse(input) {
+        return typeof input.data === "number" ? { status: "valid", value: input.data } : INVALID;
+    }
+}
+export class ObjectSchema extends Schema {
+    _parse(input) {
+        if (input.data === null || typeof input.data !== "object") return INVALID;
+        const pairs = [];
+        for (const key of Object.keys(this._def.shape)) {
+            pairs.push({ key, value: this._def.shape[key]._parse({ data: input.data[key], async: input.async }) });
+        }
+        return input.async ? Status.mergeAsync(pairs) : Status.mergeSync(pairs);
+    }
+}
+export class RecordSchema extends Schema {
+    _parse(input) {
+        if (input.data === null || typeof input.data !== "object") return INVALID;
+        const pairs = [];
+        for (const key in input.data) {
+            pairs.push({ key, value: this._def.valueType._parse({ data: input.data[key], async: input.async }) });
+        }
+        return input.async ? Status.mergeAsync(pairs) : Status.mergeSync(pairs);
+    }
+}
+export class MapSchema extends Schema {
+    _parse(input) {
+        if (!(input.data instanceof Map)) return INVALID;
+        const finish = () => {
+            const out = new Map();
+            for (const [k, v] of input.data) {
+                if (this._def.valueType._parse({ data: v, async: false }).status !== "valid") return INVALID;
+                out.set(k, v);
+            }
+            return { status: "valid", value: out };
+        };
+        return input.async ? Promise.resolve().then(finish) : finish();
+    }
+}
+export class SetSchema extends Schema {
+    _parse(input) {
+        if (!(input.data instanceof Set)) return INVALID;
+        const finish = () => {
+            const out = new Set();
+            for (const v of input.data) {
+                if (this._def.valueType._parse({ data: v, async: false }).status !== "valid") return INVALID;
+                out.add(v);
+            }
+            return { status: "valid", value: out };
+        };
+        return input.async ? Promise.resolve().then(finish) : finish();
+    }
+}
+export const number = () => new NumberSchema({ name: "number" });
+export const object = (shape) => new ObjectSchema({ name: "object", shape });
+export const record = (valueType) => new RecordSchema({ name: "record", valueType });
+export const map = (valueType) => new MapSchema({ name: "map", valueType });
+export const set = (valueType) => new SetSchema({ name: "set", valueType });
+// Untyped readers of the parse step's method value.
+export const stepKinds = (schema) => typeof schema._parse + " " + typeof Object.getPrototypeOf(schema)._parse;
+export const stepDetached = async (schema, data) => {
+    const step = schema._parse;
+    const sync = step.call(schema, { data, async: false });
+    const later = await step.call(schema, { data, async: true });
+    return sync.status + " " + later.status;
+};
diff --git a/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/package.json b/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/package.json
new file mode 100644
index 0000000000..1160994b13
--- /dev/null
+++ b/tests/corpus/6592-promise-armed-method-values/node_modules/status-schema/package.json
@@ -0,0 +1 @@
+{ "name": "status-schema", "version": "1.0.0", "type": "module", "main": "index.js", "types": "index.d.ts" }