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Fix assignability of unconstrained T[K] #23768

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Merged
merged 3 commits into from
Apr 29, 2018
Merged

Fix assignability of unconstrained T[K] #23768

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fc2f16c
Treat unconstrained T[K] the same as unconstrained T
ahejlsberg Apr 29, 2018
936444a
Add tests
ahejlsberg Apr 29, 2018
f46040b
Accept new baselines
ahejlsberg Apr 29, 2018
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33 changes: 11 additions & 22 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -10670,23 +10670,8 @@ namespace ts {
}
}

if (source.flags & TypeFlags.TypeParameter) {
let constraint = getConstraintForRelation(<TypeParameter>source);
// A type parameter with no constraint is not related to the non-primitive object type.
if (constraint || !(target.flags & TypeFlags.NonPrimitive)) {
if (!constraint || constraint.flags & TypeFlags.Any) {
constraint = emptyObjectType;
}
// Report constraint errors only if the constraint is not the empty object type
const reportConstraintErrors = reportErrors && constraint !== emptyObjectType;
if (result = isRelatedTo(constraint, target, reportConstraintErrors)) {
errorInfo = saveErrorInfo;
return result;
}
}
}
else if (source.flags & TypeFlags.IndexedAccess) {
if (target.flags & TypeFlags.IndexedAccess) {
if (source.flags & TypeFlags.TypeVariable) {
if (source.flags & TypeFlags.IndexedAccess && target.flags & TypeFlags.IndexedAccess) {
// A type S[K] is related to a type T[J] if S is related to T and K is related to J.
if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
result &= isRelatedTo((<IndexedAccessType>source).indexType, (<IndexedAccessType>target).indexType, reportErrors);
Expand All @@ -10696,11 +10681,15 @@ namespace ts {
return result;
}
}
// A type S[K] is related to a type T if C is related to T, where C is the
// constraint of S[K].
const constraint = getConstraintForRelation(<IndexedAccessType>source);
if (constraint) {
if (result = isRelatedTo(constraint, target, reportErrors)) {
let constraint = getConstraintForRelation(<TypeParameter>source);
// A type variable with no constraint is not related to the non-primitive object type.
if (constraint || !(target.flags & TypeFlags.NonPrimitive)) {
if (!constraint || constraint.flags & TypeFlags.Any) {
constraint = emptyObjectType;
}
// Report constraint errors only if the constraint is not the empty object type
const reportConstraintErrors = reportErrors && constraint !== emptyObjectType;
if (result = isRelatedTo(constraint, target, reportConstraintErrors)) {
errorInfo = saveErrorInfo;
return result;
}
Expand Down
70 changes: 70 additions & 0 deletions tests/baselines/reference/keyofAndIndexedAccess.js
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Original file line number Diff line number Diff line change
Expand Up @@ -319,6 +319,20 @@ function f90<T extends S2, K extends keyof S2>(x1: S2[keyof S2], x2: T[keyof S2]
x4.length;
}

function f91<T, K extends keyof T>(x: T, y: T[keyof T], z: T[K]) {
let a: {};
a = x;
a = y;
a = z;
}

function f92<T, K extends keyof T>(x: T, y: T[keyof T], z: T[K]) {
let a: {} | null | undefined;
a = x;
a = y;
a = z;
}

// Repros from #12011

class Base {
Expand Down Expand Up @@ -592,6 +606,27 @@ type DynamicDBRecord<Flag extends string> = ({ dynamicField: number } | { dynami
function getFlagsFromDynamicRecord<Flag extends string>(record: DynamicDBRecord<Flag>, flags: Flag[]) {
return record[flags[0]];
}

// Repro from #21368

interface I {
foo: string;
}

declare function take<T>(p: T): void;

function fn<T extends I, K extends keyof T>(o: T, k: K) {
take<{} | null | undefined>(o[k]);
take<any>(o[k]);
}

// Repro from #23133

class Unbounded<T> {
foo(x: T[keyof T]) {
let y: {} | undefined | null = x;
}
}


//// [keyofAndIndexedAccess.js]
Expand Down Expand Up @@ -830,6 +865,18 @@ function f90(x1, x2, x3, x4) {
x3.length;
x4.length;
}
function f91(x, y, z) {
var a;
a = x;
a = y;
a = z;
}
function f92(x, y, z) {
var a;
a = x;
a = y;
a = z;
}
// Repros from #12011
var Base = /** @class */ (function () {
function Base() {
Expand Down Expand Up @@ -986,6 +1033,19 @@ function getFlagsFromSimpleRecord(record, flags) {
function getFlagsFromDynamicRecord(record, flags) {
return record[flags[0]];
}
function fn(o, k) {
take(o[k]);
take(o[k]);
}
// Repro from #23133
var Unbounded = /** @class */ (function () {
function Unbounded() {
}
Unbounded.prototype.foo = function (x) {
var y = x;
};
return Unbounded;
}());


//// [keyofAndIndexedAccess.d.ts]
Expand Down Expand Up @@ -1126,6 +1186,8 @@ declare type S2 = {
b: string;
};
declare function f90<T extends S2, K extends keyof S2>(x1: S2[keyof S2], x2: T[keyof S2], x3: S2[K], x4: T[K]): void;
declare function f91<T, K extends keyof T>(x: T, y: T[keyof T], z: T[K]): void;
declare function f92<T, K extends keyof T>(x: T, y: T[keyof T], z: T[K]): void;
declare class Base {
get<K extends keyof this>(prop: K): this[K];
set<K extends keyof this>(prop: K, value: this[K]): void;
Expand Down Expand Up @@ -1298,3 +1360,11 @@ declare type DynamicDBRecord<Flag extends string> = ({
dynamicField: string;
}) & DBBoolTable<Flag>;
declare function getFlagsFromDynamicRecord<Flag extends string>(record: DynamicDBRecord<Flag>, flags: Flag[]): DynamicDBRecord<Flag>[Flag];
interface I {
foo: string;
}
declare function take<T>(p: T): void;
declare function fn<T extends I, K extends keyof T>(o: T, k: K): void;
declare class Unbounded<T> {
foo(x: T[keyof T]): void;
}
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