Type checking is ignored with spread operator, especially with truthy expression. #57248

type Type = {
    property: string,
}

let typedVar1: Type = {
    property: 'string',
    anotherProperty: 'foo', // TS-2353: Object literal may only specify known properties, and 'anotherProperty' does not exist in type 'Type'.
}

let typedVar2: Type = {
    property: 'string',
    ...({anotherProperty: 'bar'}), // No error
}

let typedVar3: Type = {
    property: 'string',
    anotherProperty: 'foo', // TS-2783: 'anotherProperty' is specified more than once, so this usage will be overwritten.
    ...({anotherProperty: 'bar'}),
}

let typedVar4: Type = {
    property: 'string',
    anotherProperty: 'foo', // No error, total ingoring
    ...(1 == 1 && {anotherProperty: 'bar'}),
}

console.log(typedVar2); // {"property": "string", "anotherProperty": "bar"} 
console.log(typedVar2.anotherProperty); // TS-2339 : Property 'anotherProperty' does not exist on type 'Type'.
console.log(typedVar4); // {"property": "string", "anotherProperty": "bar"} 
console.log(typedVar4.anotherProperty); // TS-2339 : Property 'anotherProperty' does not exist on type 'Type'.