scriptc/tests/diagnostics/blocked-binding-cascade.ts

// Uses of a binding whose DECLARATION was blocked report the SC2004
// cascade — "inherits the blocker on its declaration" — instead of
// misattributing the reference itself. The root diagnostic stays on the
// declaration site; every use points back at it.

// A poisoned declaration (WeakMap values are fenced, and the type can't
// be salvaged): uses of 'w' cascade — reads and writes alike. (This
// battery used Symbol before symbol values grew a lowering.)
let w = new WeakMap<object, number>();
console.log(typeof w);
w = new WeakMap<object, number>();

// A signature-blocked function (WeakMap return type) used as a value: the
// deferred signature diagnostic flushes at the reference, and the value
// use itself cascades.
function makeWm(): WeakMap<object, number> {
  return new WeakMap<object, number>();
}
const f = makeWm;