@studnicky/no-unparsed-assertion

Disallows a TypeScript assertion from an unknown or any value to a named type reference, including the legacy <Type>value form. A named type assertion presents a shape as proven without parsing the source value, so it bypasses the entity boundary. The rule uses TypeScript type information and does nothing when parser services are unavailable.

Assertions inside an entity namespace’s intake member are allowed, because intake is the parsing boundary. Literal as const assertions and widening assertions to unknown, object, or primitive keyword types are also allowed.

Fixable: No · Options: Yes · Suggested severity: error

Options

Name	Type	Default	Description
exemptPackages	string[]	['@studnicky/types', '@studnicky/eslint-config', '@studnicky/intake-kit']	Package names whose files are excluded from the rule.

✗ Incorrect

type Payload = { readonly value: string };
declare const raw: unknown;
const payload = raw as Payload;

type Payload = { readonly value: string };
declare const raw: unknown;
const payload = <Payload>raw;

✓ Correct

namespace PayloadEntity {
  export type Type = { readonly value: string };
  export function intake(input: unknown): Type {
    return input as Type;
  }
}

const payload = { value: 'parsed' } as const;

declare const raw: unknown;
const widened = raw as unknown;

type Payload = { readonly value: string };
declare const parsed: Payload;
const repeated = parsed as Payload;

type ForeignNode = { readonly kind: string };
declare const raw: unknown;
const node = raw as ForeignNode;

Rationale

all-types-are-entities, whole-canonical-types, folder-content-shape, and intake-parse-only make an entity type evidence that its value passed through an entity’s parsing boundary. An assertion from unknown or any to a named type forges that evidence, so this rule closes the remaining escape hatch.

@studnicky/types is exempt because it supplies the narrowing primitives that parsers are built from. @studnicky/eslint-config is exempt because it works with foreign ESLint and TypeScript AST node shapes rather than application data; the repository’s assertions in that package describe those foreign shapes.