- An arrow function or method on the right of an untyped `instanceof`
has no prototype. Node throws "Function has non-object prototype
'undefined' in instanceof check" for any object, but the runtime threw
only for plain objects, arrays and functions, and answered false for
typed arrays, native handles, promises and typed references. It now
answers false only for primitives.
- Coverage lowers the body of a signature-blocked function for its
diagnostics. A declared `this` parameter now gives that body its
receiver, as lowerFunction does, so `this.label` reports nothing.
Before, each use reported SC1080.
- An empty `[]` whose own type is `never[]` (a `return []` in an async
function, whose contextual type is `T[] | PromiseLike<T[]>`, or an
object literal's `files: []` field) builds as the unit-only element
array, like the empty tuple, so typed array slots receive it through
the checked empty-array lift. It was `number[]`, so `string[]` slots
refused it with SC1090 or SC2002.
- The refusal "instanceof against this native constructor" names its
site, and coverage lists the sites whose right-hand side is `Object` or
`Function`, which always reach it. An arrow function or method on the
right of an untyped `instanceof` throws Node's "Function has non-object
prototype" TypeError for an object.
- Coverage lists the diagnostics of a function whose signature did not
compile. A use of a parameter whose type did not compile reports SC2004.
- Coverage lists deferred fences in a module's top-level code under "runs
at startup", and the diagnostics envelope marks them `startup: true`.
Chris Tate