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Merge pull request #31572 from microsoft/normalizedIntersectionLimiter
Limit size of union types resulting from intersection type normalization
2 parents b460d8c + 01d1514 commit 7ff97d1

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‎src/compiler/checker.ts

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@@ -9912,6 +9912,12 @@ namespace ts {
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else {
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// We are attempting to construct a type of the form X & (A | B) & Y. Transform this into a type of
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// the form X & A & Y | X & B & Y and recursively reduce until no union type constituents remain.
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// If the estimated size of the resulting union type exceeds 100000 constituents, report an error.
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const size = reduceLeft(typeSet, (n, t) => n * (t.flags & TypeFlags.Union ? (<UnionType>t).types.length : 1), 1);
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if (size >= 100000) {
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error(currentNode, Diagnostics.Expression_produces_a_union_type_that_is_too_complex_to_represent);
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return errorType;
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}
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const unionIndex = findIndex(typeSet, t => (t.flags & TypeFlags.Union) !== 0);
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const unionType = <UnionType>typeSet[unionIndex];
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result = getUnionType(map(unionType.types, t => getIntersectionType(replaceElement(typeSet, unionIndex, t))),

‎tests/baselines/reference/normalizedIntersectionTooComplex.errors.txt

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tests/cases/compiler/normalizedIntersectionTooComplex.ts(36,14): error TS2590: Expression produces a union type that is too complex to represent.
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tests/cases/compiler/normalizedIntersectionTooComplex.ts(36,40): error TS7006: Parameter 'x' implicitly has an 'any' type.
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==== tests/cases/compiler/normalizedIntersectionTooComplex.ts (2 errors) ====
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// Repro from #30050
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interface Obj<T> {
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ref: T;
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}
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interface Func<T> {
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(x: T): void;
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}
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type UnionToIntersection<U> = (U extends any ? (k: U) => void : never) extends ((k: infer I) => void) ? I : never;
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type CtorOf<T> = (arg: UnionToIntersection<T>) => T;
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interface Big {
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"0": { common?: string; "0"?: number, ref?: Obj<Big["0"]> | Func<Big["0"]>; }
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"1": { common?: string; "1"?: number, ref?: Obj<Big["1"]> | Func<Big["1"]>; }
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"2": { common?: string; "2"?: number, ref?: Obj<Big["2"]> | Func<Big["2"]>; }
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"3": { common?: string; "3"?: number, ref?: Obj<Big["3"]> | Func<Big["3"]>; }
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"4": { common?: string; "4"?: number, ref?: Obj<Big["4"]> | Func<Big["4"]>; }
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"5": { common?: string; "5"?: number, ref?: Obj<Big["5"]> | Func<Big["5"]>; }
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"6": { common?: string; "6"?: number, ref?: Obj<Big["6"]> | Func<Big["6"]>; }
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"7": { common?: string; "7"?: number, ref?: Obj<Big["7"]> | Func<Big["7"]>; }
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"8": { common?: string; "8"?: number, ref?: Obj<Big["8"]> | Func<Big["8"]>; }
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"9": { common?: string; "9"?: number, ref?: Obj<Big["9"]> | Func<Big["9"]>; }
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"10": { common?: string; "10"?: number, ref?: Obj<Big["10"]> | Func<Big["10"]>; }
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"11": { common?: string; "11"?: number, ref?: Obj<Big["11"]> | Func<Big["11"]>; }
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"12": { common?: string; "12"?: number, ref?: Obj<Big["12"]> | Func<Big["12"]>; }
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"13": { common?: string; "13"?: number, ref?: Obj<Big["13"]> | Func<Big["13"]>; }
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"14": { common?: string; "14"?: number, ref?: Obj<Big["14"]> | Func<Big["14"]>; }
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"15": { common?: string; "15"?: number, ref?: Obj<Big["15"]> | Func<Big["15"]>; }
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"16": { common?: string; "16"?: number, ref?: Obj<Big["16"]> | Func<Big["16"]>; }
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"17": { common?: string; "17"?: number, ref?: Obj<Big["17"]> | Func<Big["17"]>; }
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}
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declare function getCtor<T extends keyof Big>(comp: T): CtorOf<Big[T]>
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declare var all: keyof Big;
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const ctor = getCtor(all);
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const comp = ctor({ common: "ok", ref: x => console.log(x) });
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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!!! error TS2590: Expression produces a union type that is too complex to represent.
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~
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!!! error TS7006: Parameter 'x' implicitly has an 'any' type.
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‎tests/baselines/reference/normalizedIntersectionTooComplex.js

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//// [normalizedIntersectionTooComplex.ts]
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// Repro from #30050
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interface Obj<T> {
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ref: T;
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}
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interface Func<T> {
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(x: T): void;
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}
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type UnionToIntersection<U> = (U extends any ? (k: U) => void : never) extends ((k: infer I) => void) ? I : never;
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type CtorOf<T> = (arg: UnionToIntersection<T>) => T;
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interface Big {
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"0": { common?: string; "0"?: number, ref?: Obj<Big["0"]> | Func<Big["0"]>; }
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"1": { common?: string; "1"?: number, ref?: Obj<Big["1"]> | Func<Big["1"]>; }
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"2": { common?: string; "2"?: number, ref?: Obj<Big["2"]> | Func<Big["2"]>; }
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"3": { common?: string; "3"?: number, ref?: Obj<Big["3"]> | Func<Big["3"]>; }
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"4": { common?: string; "4"?: number, ref?: Obj<Big["4"]> | Func<Big["4"]>; }
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"5": { common?: string; "5"?: number, ref?: Obj<Big["5"]> | Func<Big["5"]>; }
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"6": { common?: string; "6"?: number, ref?: Obj<Big["6"]> | Func<Big["6"]>; }
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"7": { common?: string; "7"?: number, ref?: Obj<Big["7"]> | Func<Big["7"]>; }
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"8": { common?: string; "8"?: number, ref?: Obj<Big["8"]> | Func<Big["8"]>; }
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"9": { common?: string; "9"?: number, ref?: Obj<Big["9"]> | Func<Big["9"]>; }
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"10": { common?: string; "10"?: number, ref?: Obj<Big["10"]> | Func<Big["10"]>; }
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"11": { common?: string; "11"?: number, ref?: Obj<Big["11"]> | Func<Big["11"]>; }
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"12": { common?: string; "12"?: number, ref?: Obj<Big["12"]> | Func<Big["12"]>; }
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"13": { common?: string; "13"?: number, ref?: Obj<Big["13"]> | Func<Big["13"]>; }
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"14": { common?: string; "14"?: number, ref?: Obj<Big["14"]> | Func<Big["14"]>; }
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"15": { common?: string; "15"?: number, ref?: Obj<Big["15"]> | Func<Big["15"]>; }
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"16": { common?: string; "16"?: number, ref?: Obj<Big["16"]> | Func<Big["16"]>; }
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"17": { common?: string; "17"?: number, ref?: Obj<Big["17"]> | Func<Big["17"]>; }
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}
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declare function getCtor<T extends keyof Big>(comp: T): CtorOf<Big[T]>
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declare var all: keyof Big;
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const ctor = getCtor(all);
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const comp = ctor({ common: "ok", ref: x => console.log(x) });
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//// [normalizedIntersectionTooComplex.js]
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"use strict";
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// Repro from #30050
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var ctor = getCtor(all);
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var comp = ctor({ common: "ok", ref: function (x) { return console.log(x); } });

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