One of the ivy acceptance tests currently fails in IE10. This
is because we recently added a new test that asserts that injecting
`ViewRef` results in a `NullInjectorError`.
Due to limitations in TypeScript and in polyfills for `setPrototypeOf`,
the error cannot be thrown as `ViewRef` is always considered injectable.
In reality, `ViewRef` should not be injectable, as explicitly noted
in c00f4ab2ae.
There seems no way to simulate the proper prototype chain in such
browsers that do not natively support `__proto__`, so TypeScript
and `core-js` polyfills simply break the prototype chain and
assign inherited properties directly on `ViewRef`. i.e. so that
`ViewRef.__NG_ELEMENT_ID__` exists and DI picks it up.
There is a way for TypeScript to theoretically generate proper
prototype chain in ES5 output, but they intend to only bother
about the proper prototype chain in ES6 where `setPrototypeOf`
etc. are offically standarized. See the response:
https://github.com/microsoft/TypeScript/issues/1601#issuecomment-94892833.
PR Close#37892
6b731a067a