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AndaristAndarist
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Fixed an issue with missingType narrowing by case undefined in default cases (#58001)
1 parent 33b1561 commit f01cae8

10 files changed

Lines changed: 837 additions & 1 deletion

‎src/compiler/checker.ts‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -28543,7 +28543,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
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if (!hasDefaultClause) {
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return caseType;
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}
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const defaultType = filterType(type, t => !(isUnitLikeType(t) && contains(switchTypes, getRegularTypeOfLiteralType(extractUnitType(t)))));
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const defaultType = filterType(type, t => !(isUnitLikeType(t) && contains(switchTypes, t.flags & TypeFlags.Undefined ? undefinedType : getRegularTypeOfLiteralType(extractUnitType(t)))));
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return caseType.flags & TypeFlags.Never ? defaultType : getUnionType([caseType, defaultType]);
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}
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‎tests/baselines/reference/narrowBySwitchDiscriminantUndefinedCase1(exactoptionalpropertytypes=false,nouncheckedindexedaccess=false).symbols‎

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//// [tests/cases/compiler/narrowBySwitchDiscriminantUndefinedCase1.ts] ////
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=== narrowBySwitchDiscriminantUndefinedCase1.ts ===
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// https://github.com/microsoft/TypeScript/issues/57999
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interface A {
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>A : Symbol(A, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 0, 0))
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optionalProp?: "hello";
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>optionalProp : Symbol(A.optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 2, 13))
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}
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function func(arg: A) {
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>func : Symbol(func, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 4, 1))
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>arg : Symbol(arg, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 6, 14))
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>A : Symbol(A, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 0, 0))
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const { optionalProp } = arg;
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 7, 9))
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>arg : Symbol(arg, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 6, 14))
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switch (optionalProp) {
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 7, 9))
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case undefined:
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>undefined : Symbol(undefined)
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return undefined;
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>undefined : Symbol(undefined)
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case "hello":
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return "hello";
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default:
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assertUnreachable(optionalProp);
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>assertUnreachable : Symbol(assertUnreachable, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 30, 1))
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 7, 9))
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}
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}
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function func2() {
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>func2 : Symbol(func2, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 17, 1))
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const optionalProp = ["hello" as const][Math.random()];
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 20, 7))
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>const : Symbol(const)
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>Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
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>Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
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>random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
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switch (optionalProp) {
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 20, 7))
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case undefined:
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>undefined : Symbol(undefined)
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return undefined;
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>undefined : Symbol(undefined)
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case "hello":
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return "hello";
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default:
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assertUnreachable(optionalProp);
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>assertUnreachable : Symbol(assertUnreachable, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 30, 1))
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 20, 7))
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}
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}
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function assertUnreachable(_: never): never {
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>assertUnreachable : Symbol(assertUnreachable, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 30, 1))
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>_ : Symbol(_, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 32, 27))
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throw new Error("Unreachable path taken");
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>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
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}
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‎tests/baselines/reference/narrowBySwitchDiscriminantUndefinedCase1(exactoptionalpropertytypes=false,nouncheckedindexedaccess=false).types‎

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//// [tests/cases/compiler/narrowBySwitchDiscriminantUndefinedCase1.ts] ////
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=== narrowBySwitchDiscriminantUndefinedCase1.ts ===
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// https://github.com/microsoft/TypeScript/issues/57999
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interface A {
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optionalProp?: "hello";
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>optionalProp : "hello" | undefined
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> : ^^^^^^^^^^^^^^^^^^^
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}
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function func(arg: A) {
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>func : (arg: A) => "hello" | undefined
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> : ^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^
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>arg : A
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> : ^
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const { optionalProp } = arg;
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>optionalProp : "hello" | undefined
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> : ^^^^^^^^^^^^^^^^^^^
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>arg : A
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> : ^
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switch (optionalProp) {
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>optionalProp : "hello" | undefined
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> : ^^^^^^^^^^^^^^^^^^^
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case undefined:
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>undefined : undefined
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> : ^^^^^^^^^
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return undefined;
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>undefined : undefined
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> : ^^^^^^^^^
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case "hello":
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>"hello" : "hello"
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> : ^^^^^^^
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return "hello";
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>"hello" : "hello"
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> : ^^^^^^^
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default:
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assertUnreachable(optionalProp);
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>assertUnreachable(optionalProp) : never
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> : ^^^^^
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>assertUnreachable : (_: never) => never
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> : ^^^^^^^^^^^^^^^^^^^
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>optionalProp : never
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> : ^^^^^
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}
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}
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function func2() {
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>func2 : () => "hello" | undefined
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> : ^^^^^^^^^^^^^^^^^^^^^^^^^
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const optionalProp = ["hello" as const][Math.random()];
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>optionalProp : "hello"
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> : ^^^^^^^
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>["hello" as const][Math.random()] : "hello"
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> : ^^^^^^^
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>["hello" as const] : "hello"[]
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> : ^^^^^^^^^
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>"hello" as const : "hello"
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> : ^^^^^^^
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>"hello" : "hello"
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> : ^^^^^^^
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>Math.random() : number
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> : ^^^^^^
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>Math.random : () => number
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> : ^^^^^^^^^^^^
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>Math : Math
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> : ^^^^
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>random : () => number
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> : ^^^^^^^^^^^^
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switch (optionalProp) {
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>optionalProp : "hello"
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> : ^^^^^^^
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case undefined:
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>undefined : undefined
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> : ^^^^^^^^^
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return undefined;
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>undefined : undefined
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> : ^^^^^^^^^
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case "hello":
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>"hello" : "hello"
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> : ^^^^^^^
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return "hello";
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>"hello" : "hello"
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> : ^^^^^^^
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default:
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assertUnreachable(optionalProp);
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>assertUnreachable(optionalProp) : never
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> : ^^^^^
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>assertUnreachable : (_: never) => never
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> : ^^^^^^^^^^^^^^^^^^^
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>optionalProp : never
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> : ^^^^^
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}
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}
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function assertUnreachable(_: never): never {
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>assertUnreachable : (_: never) => never
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> : ^^^^ ^^^^^
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>_ : never
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> : ^^^^^
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throw new Error("Unreachable path taken");
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>new Error("Unreachable path taken") : Error
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> : ^^^^^
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>Error : ErrorConstructor
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> : ^^^^^^^^^^^^^^^^
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>"Unreachable path taken" : "Unreachable path taken"
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> : ^^^^^^^^^^^^^^^^^^^^^^^^
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}
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‎tests/baselines/reference/narrowBySwitchDiscriminantUndefinedCase1(exactoptionalpropertytypes=false,nouncheckedindexedaccess=true).symbols‎

Lines changed: 75 additions & 0 deletions
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//// [tests/cases/compiler/narrowBySwitchDiscriminantUndefinedCase1.ts] ////
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=== narrowBySwitchDiscriminantUndefinedCase1.ts ===
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// https://github.com/microsoft/TypeScript/issues/57999
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interface A {
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>A : Symbol(A, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 0, 0))
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optionalProp?: "hello";
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>optionalProp : Symbol(A.optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 2, 13))
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}
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function func(arg: A) {
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>func : Symbol(func, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 4, 1))
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>arg : Symbol(arg, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 6, 14))
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>A : Symbol(A, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 0, 0))
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const { optionalProp } = arg;
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 7, 9))
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>arg : Symbol(arg, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 6, 14))
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switch (optionalProp) {
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 7, 9))
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case undefined:
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>undefined : Symbol(undefined)
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return undefined;
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>undefined : Symbol(undefined)
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case "hello":
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return "hello";
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default:
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assertUnreachable(optionalProp);
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>assertUnreachable : Symbol(assertUnreachable, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 30, 1))
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 7, 9))
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}
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}
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function func2() {
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>func2 : Symbol(func2, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 17, 1))
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const optionalProp = ["hello" as const][Math.random()];
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 20, 7))
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>const : Symbol(const)
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>Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
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>Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
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>random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
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switch (optionalProp) {
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 20, 7))
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case undefined:
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>undefined : Symbol(undefined)
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return undefined;
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>undefined : Symbol(undefined)
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case "hello":
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return "hello";
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default:
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assertUnreachable(optionalProp);
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>assertUnreachable : Symbol(assertUnreachable, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 30, 1))
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>optionalProp : Symbol(optionalProp, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 20, 7))
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}
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}
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function assertUnreachable(_: never): never {
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>assertUnreachable : Symbol(assertUnreachable, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 30, 1))
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>_ : Symbol(_, Decl(narrowBySwitchDiscriminantUndefinedCase1.ts, 32, 27))
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throw new Error("Unreachable path taken");
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>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
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}
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