69 lines
No EOL
1.2 KiB
TypeScript
69 lines
No EOL
1.2 KiB
TypeScript
// @strictNullChecks: true
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type Item = Item1 | Item2;
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interface Base {
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bar: boolean;
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}
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interface Item1 extends Base {
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kind: "A";
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foo: string | undefined;
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baz: boolean;
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qux: true;
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}
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interface Item2 extends Base {
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kind: "B";
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foo: string | undefined;
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baz: boolean;
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qux: false;
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}
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function goo1(x: Item) {
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if (x.kind === "A" && x.foo !== undefined) {
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x.foo.length;
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}
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}
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function goo2(x: Item) {
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if (x.foo !== undefined && x.kind === "A") {
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x.foo.length; // Error, intervening discriminant guard
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}
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}
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function foo1(x: Item) {
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if (x.bar && x.foo !== undefined) {
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x.foo.length;
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}
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}
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function foo2(x: Item) {
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if (x.foo !== undefined && x.bar) {
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x.foo.length;
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}
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}
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function foo3(x: Item) {
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if (x.baz && x.foo !== undefined) {
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x.foo.length;
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}
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}
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function foo4(x: Item) {
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if (x.foo !== undefined && x.baz) {
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x.foo.length;
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}
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}
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function foo5(x: Item) {
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if (x.qux && x.foo !== undefined) {
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x.foo.length;
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}
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}
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function foo6(x: Item) {
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if (x.foo !== undefined && x.qux) {
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x.foo.length; // Error, intervening discriminant guard
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}
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} |