Type narrowing down on a union type with null results in incorrect type when applying `typeof`

Bug Report

🔎 Search Terms

type narrowing down, typeof

🕗 Version & Regression Information

I've tested all versions until 4.4.0 (Nightly)

⏯ Playground Link

https://www.typescriptlang.org/play?ts=4.4.0-dev.20210706#code/C4TwDgpgBAwg9gO2AQwJYIgJygXigbygGNEV0sAuA0SKgIgDM446BfKAH2vAnoCNkmNpygIArgBsJUVgFgAUAoZiERYKkRRgEAM7AAFOjBjgVeEjQZMASgIKoDqKgZRDCY8AB0JC+UwB+TxpoHFCoAHImOHDbfHtHBIB6RKgAdzhMAGsdeISHZCIiCDBgHQAxZjcPb1JLLGsAbly8gqKS8sr8YPootmtmpJSAEThdUThgNIzsgcdW4tKKuCqTGt8rKGQdLR44FyNVnzIrfvk8ucKFjuWunh7mYS2dyD2nd0Pav1OEuXlfpRUag0CE2l3aSxWpm4tCgjAerFirCAA

💻 Code

type Container = { container: {type: "foo"} | {type: "bar"} | null }

function test(input: Container) {
    if (input.container?.type === 'foo') {
        // works
        acceptsFoo(input.container);
        acceptsFoo({type: "foo"})
        // Does not works
        acceptsFoo(input.container as typeof input.container)
        acceptsFoo({type: "foo"} as typeof input.container)
		/**
Error:
 Argument of type '{ type: "foo"; } | null' is not assignable to parameter of type '{ type: "foo"; }'.
  Type 'null' is not assignable to type '{ type: "foo"; }'.(2345) \
**/
    }
}

function acceptsFoo(input: {type: "foo"}) {}

🙁 Actual behavior

input.container and input.container as typeof input.container are not equivalent.

🙂 Expected behavior

input.container and input.container as typeof input.container should be equivalent.

Reproduisez le comportement de narrowing signalé dans le TypeScript Playground lié en utilisant le Container et la fonction de test fournis. Commencez par suivre le traitement par le vérificateur de types du narrowing des propriétés optionnelles et des assertions typeof ; c’est terminé lorsque input.container et input.container as typeof input.container sont traités de manière équivalente sans l’erreur de nullabilité.