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tests/cases/conformance/types/spread/objectSpreadStrictNull.ts(14,9): error TS2322: Type '{ sn: number | undefined; }' is not assignable to type '{ sn: string | number; }'.
Types of property 'sn' are incompatible.
Type 'number | undefined' is not assignable to type 'string | number'.
Type 'undefined' is not assignable to type 'string | number'.
tests/cases/conformance/types/spread/objectSpreadStrictNull.ts(15,9): error TS2322: Type '{ sn: number | undefined; }' is not assignable to type '{ sn: string | number; }'.
Types of property 'sn' are incompatible.
Type 'number | undefined' is not assignable to type 'string | number'.
tests/cases/conformance/types/spread/objectSpreadStrictNull.ts(18,9): error TS2322: Type '{ sn: string | number | undefined; }' is not assignable to type '{ sn: string | number | boolean; }'.
Types of property 'sn' are incompatible.
Type 'string | number | undefined' is not assignable to type 'string | number | boolean'.
Type 'undefined' is not assignable to type 'string | number | boolean'.
tests/cases/conformance/types/spread/objectSpreadStrictNull.ts(28,26): error TS2322: Type 'undefined' is not assignable to type 'string'.
tests/cases/conformance/types/spread/objectSpreadStrictNull.ts(42,5): error TS2322: Type '{ foo: number | undefined; bar: string | undefined; }' is not assignable to type 'Fields'.
Types of property 'foo' are incompatible.
Type 'number | undefined' is not assignable to type 'number'.
Type 'undefined' is not assignable to type 'number'.
==== tests/cases/conformance/types/spread/objectSpreadStrictNull.ts (5 errors) ====
function f(
definiteBoolean: { sn: boolean },
definiteString: { sn: string },
optionalString: { sn?: string },
optionalNumber: { sn?: number },
undefinedString: { sn: string | undefined },
undefinedNumber: { sn: number | undefined }) {
// optional
let optionalUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
// undefined
let undefinedUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedNumber };
~~~~~~~~~~~~~~~~~~~
!!! error TS2322: Type '{ sn: number | undefined; }' is not assignable to type '{ sn: string | number; }'.
!!! error TS2322: Types of property 'sn' are incompatible.
!!! error TS2322: Type 'number | undefined' is not assignable to type 'string | number'.
!!! error TS2322: Type 'undefined' is not assignable to type 'string | number'.
let undefinedUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedString, ...undefinedNumber };
~~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2322: Type '{ sn: number | undefined; }' is not assignable to type '{ sn: string | number; }'.
!!! error TS2322: Types of property 'sn' are incompatible.
!!! error TS2322: Type 'number | undefined' is not assignable to type 'string | number'.
let allUndefined: { sn: string | number | undefined } = { ...undefinedString, ...undefinedNumber };
let undefinedWithOptionalContinues: { sn: string | number | boolean } = { ...definiteBoolean, ...undefinedString, ...optionalNumber };
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2322: Type '{ sn: string | number | undefined; }' is not assignable to type '{ sn: string | number | boolean; }'.
!!! error TS2322: Types of property 'sn' are incompatible.
!!! error TS2322: Type 'string | number | undefined' is not assignable to type 'string | number | boolean'.
!!! error TS2322: Type 'undefined' is not assignable to type 'string | number | boolean'.
}
type Movie = {
title: string;
yearReleased: number;
}
const m = { title: "The Matrix", yearReleased: 1999 };
// should error here because title: undefined is not assignable to string
const x: Movie = { ...m, title: undefined };
~~~~~
!!! error TS2322: Type 'undefined' is not assignable to type 'string'.
!!! related TS6500 tests/cases/conformance/types/spread/objectSpreadStrictNull.ts:22:5: The expected type comes from property 'title' which is declared here on type 'Movie'
interface Fields {
foo: number;
bar: string;
}
interface NearlyPartialFields {
foo: number | undefined;
bar: string | undefined;
}
function g(fields: Fields, partialFields: Partial<Fields>, nearlyPartialFields: NearlyPartialFields) {
// ok, undefined is stripped from optional properties when spread
fields = { ...fields, ...partialFields };
// error: not optional, undefined remains
fields = { ...fields, ...nearlyPartialFields };
~~~~~~
!!! error TS2322: Type '{ foo: number | undefined; bar: string | undefined; }' is not assignable to type 'Fields'.
!!! error TS2322: Types of property 'foo' are incompatible.
!!! error TS2322: Type 'number | undefined' is not assignable to type 'number'.
!!! error TS2322: Type 'undefined' is not assignable to type 'number'.
}
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