- A direct call drops its receiver's evaluation, so a name receiver must
hold its value whenever the read runs: a parameter, a function
declaration, or a variable declared with an initializer by an earlier
top-level statement and never assigned again. A variable read before it
is assigned (undefined, a TypeError) or in its temporal dead zone (a
ReferenceError) keeps the member read.
- A store between a constructor and its methods counts as a definition
only when its receiver is a constant object, which has no setters,
reached without running code, and its key is not `__proto__`. A store
that may run a setter keeps the constructor function, since the setter
could see the prototype without its methods.
- `propertyIsEnumerable` asked of the prototype or the constructor, or
reached other than as a direct method call, keeps the constructor
function: assigned methods are enumerable and class methods are not.
The static-ns fixture covers each case and prints what Node prints.
With the shape overlay on, a first round of structural rewrites runs before
the typed overlay (shape-inference/static-objects.ts, stage 2b of
DESIGN-constant-objects.md), proven by the constant object graphs:
- An ES5 constructor stored by a top-level statement whose prototype is a
constant object of plain methods becomes a class declaration with those
methods, when the program cannot tell: the function is only ever
constructed and never escapes, its prototype is never replaced, nothing
enumerates instances with for-in or reflects on the prototype or the
function, nothing reads their names or sources, the bodies are
strict-mode safe, and only definitions run between the constructor and
its last method.
- A constant namespace member holding a `this`-free function expression
becomes a function declaration, and reads of the member in the same file
whose receiver is exactly that constant object refer to it directly.
The rounds rerun the analysis on the rebuilt program, the overlay now also
covers the program's own JavaScript files, and the build report counts the
rewrites. A JavaScript switch whose case tests lower to another type than
the discriminant compares with === instead of being refused.
Namespace benchmark (n=20000): 1.55 s -> 0.42-0.47 s, output identical to
Node (typed TypeScript twin 85 ms, Node 21 ms).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Chris Tate