Conjunction of two disjunctions cause incorrect errors

TypeScript Version: 3.3

Search Terms:

• Conjunction

Code

interface Small {
    small: true,
    callbackWhenSmallIsFalsy?: undefined;
}

interface NotSmall {
    small?: false;
    callbackWhenSmallIsFalsy: () => void;
}

interface Green {
    green?: false
    numberWhenGreenTrue?: undefined
}

interface NotGreen {
    green: true
    numberWhenGreenTrue: number;
}

type SmallProps = Small | NotSmall;
type GreenProps = Green | NotGreen;

type Props = SmallProps & GreenProps;

const try1: Props = {
    green: true,
    numberWhenGreenTrue: 5,
    small: true
} // OK

const try2: Props = {
    green: false,
    numberWhenGreenTrue: 5,
    small: true
} // Unexpected Error: 'callbackWhenSmallIsFalsy' is missing...
// Expected Error: 5 is not assignable to undefined for 'numberWhenGreenTrue'

 const try3: Props = {
    green: false,
    small: true
} // OK

 const try4: Props = {
    green: false,
    small: true,
    callbackWhenSmallIsFalsy: () => 5
} // Acceptable Error: Types of property 'small' are incompatible.
// TS can't know which of the conditions to use, so this is okay. NTH: It lists multiple possible errors

Expected behavior:
in try3 I don't expect the error to be about callbackWhenSmallIsFalsy. I would expect an error about green or numberWhenGreenTrue

Actual behavior:
When the conjunction is evaluated as false, it appears that the compiler tries to force an error into the first part of the conjunction, when the falsehood is from the second part of the conjunction.

Playground Link:
http://www.typescriptlang.org/play/#src=interface%20Small%20%7B%0A%20%20%20%20small%3A%20true%2C%0A%20%20%20%20callbackWhenSmallIsFalsy%3F%3A%20undefined%3B%0A%7D%0A%0Ainterface%20NotSmall%20%7B%0A%20%20%20%20small%3F%3A%20false%3B%0A%20%20%20%20callbackWhenSmallIsFalsy%3A%20()%20%3D%3E%20void%3B%0A%7D%0A%0Ainterface%20Green%20%7B%0A%20%20%20%20green%3F%3A%20false%0A%20%20%20%20numberWhenGreenTrue%3F%3A%20undefined%0A%7D%0A%0Ainterface%20NotGreen%20%7B%0A%20%20%20%20green%3A%20true%0A%20%20%20%20numberWhenGreenTrue%3A%20number%3B%0A%7D%0A%0Atype%20SmallProps%20%3D%20Small%20%7C%20NotSmall%3B%0Atype%20GreenProps%20%3D%20Green%20%7C%20NotGreen%3B%0A%0Atype%20Props%20%3D%20SmallProps%20%26%20GreenProps%3B%0A%0Aconst%20try1%3A%20Props%20%3D%20%7B%0A%20%20%20%20green%3A%20true%2C%0A%20%20%20%20numberWhenGreenTrue%3A%205%2C%0A%20%20%20%20small%3A%20true%0A%7D%20%2F%2F%20OK%0A%0Aconst%20try2%3A%20Props%20%3D%20%7B%0A%20%20%20%20green%3A%20false%2C%0A%20%20%20%20numberWhenGreenTrue%3A%205%2C%0A%20%20%20%20small%3A%20true%0A%7D%20%2F%2F%20Unexpected%20Error%3A%20'callbackWhenSmallIsFalsy'%20is%20missing...%0A%2F%2F%20Expected%20Error%3A%205%20is%20not%20assignable%20to%20undefined%20for%20'numberWhenGreenTrue'%0A%0A%20const%20try3%3A%20Props%20%3D%20%7B%0A%20%20%20%20green%3A%20false%2C%0A%20%20%20%20small%3A%20true%0A%7D%20%2F%2F%20OK%0A%0A%20const%20try4%3A%20Props%20%3D%20%7B%0A%20%20%20%20green%3A%20false%2C%0A%20%20%20%20small%3A%20true%2C%0A%20%20%20%20callbackWhenSmallIsFalsy%3A%20()%20%3D%3E%205%0A%7D%20%2F%2F%20Acceptable%20Error%3A%20Types%20of%20property%20'small'%20are%20incompatible.%0A%2F%2F%20TS%20can't%20know%20which%20of%20the%20conditions%20to%20use%2C%20so%20this%20is%20okay.%20NTH%3A%20It%20lists%20multiple%20possible%20errors

Related Issues:

Inizia riproducendo l’esempio di conjunction dell’issue nel TypeScript Playground, in particolare try2 e try3, e ispeziona il comportamento del compilatore per il controllo dei tipi e la diagnostica. Il lavoro è completo quando l’errore per try2 punta a numberWhenGreenTrue o green invece che a callbackWhenSmallIsFalsy, mentre gli altri casi mostrati mantengono il comportamento previsto.