Compile SDK-declared data types, any-valued members and Pick views of classes

[cramforce]

Service code often types its messages with declarations from SDKs and shared type packages. Several of those shapes were refused, and since a message type usually reaches a provider interface, one refused member blocked every function that handled the message. The diagnostic also named only the outermost member, so finding the offending one inside a 40-member record meant bisecting by hand.

any-valued dictionaries

type Dictionary<T = any> = { [key: string]: T };
interface Build { use: string; config?: Dictionary }
interface Upload { url: string; fields: { [key: string]: any } }

An index signature whose value type is any now holds checked-dynamic values, exactly as Record<string, unknown> does. This includes a generic dictionary alias used without a type argument.

any[] members

A record member that an interface, type literal or class declares as any[], also optional or nullable, is the checked-dynamic array, as unknown[] already maps. An object literal's inferred any[] member and all other any[] positions keep their existing rules, so programs that already compiled build the same code.

Data classes declared by types-only packages

// in a package's .d.ts, never constructed: the value arrives as JSON
export declare class PresignedPost {
  url: string;
  fields: PresignedPost.Fields;
}
export declare namespace PresignedPost {
  interface Fields { Policy: string; [key: string]: string }
}

A class that a package's declaration file declares with public instance fields only (no constructor, methods, accessors, index signatures, static, private or protected members, base classes or type parameters), optionally merged with a namespace of types, describes data. It now maps structurally, like an interface, so values from JSON.parse or object literals compile as records. Its class value, which has no implementation, stays refused.

Pick and Omit views of a class

interface Context { client: Pick<ApiClient, "request"> }
function finish(client: Pick<ApiClient, "request" | "close">) { client.close(); }

Pick<C, K> and Omit<C, K> over a program class, when the view exposes a method, are treated like an interface the class matches: values keep a live receiver, so calls through the view run on the instance and share its state. Field-only views keep their record representation.

Nested member paths in record diagnostics

values of type 'Provider' cannot be compiled: the record shape is supported, but its member 'poll().jobs[].handle' has type 'Promise<number> & { cancel(): void; }', which does not compile

The record-member diagnostic now follows the failure through function results (()), promise payloads and union arms, record members (.name) and array elements ([]) down to the member it comes from. A member that holds any is named itself.

Not included

Function types with any parameters ((reason?: any) => void) are handled by #1433.

Evidence

• Corpus: 6412-any-valued-dictionaries.ts, 6413-sdk-declared-data-class (a types-only package) and 6414-pick-class-method-views.ts. All three match Node byte for byte in the plain and sanitized lanes.
• Diagnostics: a new fixture, nested-member-blocker-path.ts. Existing snapshots are unchanged, because a path stops at the member that holds an any. diagnostics.test.ts: 200/200.
• Zero-cost gate against main bf2afee: PASS, with all 2501 bench, self and corpus programs identical (IR, LLVM and release executables). The bench geomean changes by -0.23% and self-compile time by +1.31%, both within tolerance. A first run caught one corpus program whose object literal had an inferred any[] member; that is why the any[] rule is limited to declared members. The self-hosted compiler IR build exits 0 with no diagnostics. Frontend and IR unit tests: 1243/1243.
• pnpm lint and pnpm format:check are clean, and pnpm test:ts7 --baselines-only passes, with 4 new baselines and no existing ones changed.
• No compatibility rows change.

🤖 Generated with Claude Code

[vercel]

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Project	Deployment	Actions	Updated
scriptc	Ready	Preview, v0	Oct 20, 2026 5:34pm UTC

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