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Mapped types allow numeric constraint types #18346

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bd2c386
Mapped types allow numeric constraint types
sandersn Sep 8, 2017
3cd24b7
Test:numeric constraint types for mapped types
sandersn Sep 8, 2017
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44 changes: 27 additions & 17 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3119,7 +3119,7 @@ namespace ts {
}
}
if ((symbol as TransientSymbol).syntheticLiteralTypeOrigin) {
const stringValue = (symbol as TransientSymbol).syntheticLiteralTypeOrigin.value;
const stringValue = "" + (symbol as TransientSymbol).syntheticLiteralTypeOrigin.value;
if (!isIdentifierText(stringValue, compilerOptions.target)) {
return `"${escapeString(stringValue, CharacterCodes.doubleQuote)}"`;
}
Expand Down Expand Up @@ -5722,6 +5722,7 @@ namespace ts {
function resolveMappedTypeMembers(type: MappedType) {
const members: SymbolTable = createSymbolTable();
let stringIndexInfo: IndexInfo;
let numberIndexInfo: IndexInfo;
// Resolve upfront such that recursive references see an empty object type.
setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, undefined, undefined);
// In { [P in K]: T }, we refer to P as the type parameter type, K as the constraint type,
Expand Down Expand Up @@ -5749,7 +5750,7 @@ namespace ts {
const iterationType = keyType.flags & TypeFlags.Index ? getIndexType(getApparentType((<IndexType>keyType).type)) : keyType;
forEachType(iterationType, addMemberForKeyType);
}
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, undefined);
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);

function addMemberForKeyType(t: Type, propertySymbolOrIndex?: Symbol | number) {
let propertySymbol: Symbol;
Expand All @@ -5765,25 +5766,34 @@ namespace ts {
const iterationMapper = createTypeMapper([typeParameter], [t]);
const templateMapper = type.mapper ? combineTypeMappers(type.mapper, iterationMapper) : iterationMapper;
const propType = instantiateType(templateType, templateMapper);
// If the current iteration type constituent is a string literal type, create a property.
// If the current iteration type constituent is a string or number literal type, create a property.
// Otherwise, for type string create a string index signature.
if (t.flags & TypeFlags.StringLiteral) {
const propName = escapeLeadingUnderscores((<StringLiteralType>t).value);
const modifiersProp = getPropertyOfType(modifiersType, propName);
const isOptional = templateOptional || !!(modifiersProp && modifiersProp.flags & SymbolFlags.Optional);
const prop = createSymbol(SymbolFlags.Property | (isOptional ? SymbolFlags.Optional : 0), propName);
prop.checkFlags = templateReadonly || modifiersProp && isReadonlySymbol(modifiersProp) ? CheckFlags.Readonly : 0;
prop.type = propType;
if (propertySymbol) {
prop.syntheticOrigin = propertySymbol;
prop.declarations = propertySymbol.declarations;
}
prop.syntheticLiteralTypeOrigin = t as StringLiteralType;
members.set(propName, prop);
if (t.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
const propName = escapeLeadingUnderscores("" + (<StringLiteralType | NumberLiteralType>t).value);
if (members.has(propName)) {
// in case of a conflict between the literal types "1" and 1, for example, do not add either one
members.delete(propName);
}
else {
const modifiersProp = getPropertyOfType(modifiersType, propName);
const isOptional = templateOptional || !!(modifiersProp && modifiersProp.flags & SymbolFlags.Optional);
const prop = createSymbol(SymbolFlags.Property | (isOptional ? SymbolFlags.Optional : 0), propName);
prop.checkFlags = templateReadonly || modifiersProp && isReadonlySymbol(modifiersProp) ? CheckFlags.Readonly : 0;
prop.type = propType;
if (propertySymbol) {
prop.syntheticOrigin = propertySymbol;
prop.declarations = propertySymbol.declarations;
}
prop.syntheticLiteralTypeOrigin = t as StringLiteralType | NumberLiteralType;
members.set(propName, prop);
}
}
else if (t.flags & TypeFlags.String) {
stringIndexInfo = createIndexInfo(propType, templateReadonly);
}
else if (t.flags & (TypeFlags.Enum | TypeFlags.Number)) {
numberIndexInfo = createIndexInfo(propType, templateReadonly);
}
}
}

Expand Down Expand Up @@ -18856,7 +18866,7 @@ namespace ts {
checkSourceElement(node.type);
const type = <MappedType>getTypeFromMappedTypeNode(node);
const constraintType = getConstraintTypeFromMappedType(type);
checkTypeAssignableTo(constraintType, stringType, node.typeParameter.constraint);
checkTypeAssignableTo(constraintType, getUnionType([stringType, numberType]), node.typeParameter.constraint);
}

function isPrivateWithinAmbient(node: Node): boolean {
Expand Down
3 changes: 2 additions & 1 deletion src/compiler/types.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3033,7 +3033,7 @@ namespace ts {
leftSpread?: Symbol; // Left source for synthetic spread property
rightSpread?: Symbol; // Right source for synthetic spread property
syntheticOrigin?: Symbol; // For a property on a mapped or spread type, points back to the original property
syntheticLiteralTypeOrigin?: StringLiteralType; // For a property on a mapped type, indicates the type whose text to use as the declaration name, instead of the symbol name
syntheticLiteralTypeOrigin?: StringLiteralType | NumberLiteralType; // For a property on a mapped type, indicates the type whose text to use as the declaration name, instead of the symbol name
isDiscriminantProperty?: boolean; // True if discriminant synthetic property
resolvedExports?: SymbolTable; // Resolved exports of module
exportsChecked?: boolean; // True if exports of external module have been checked
Expand Down Expand Up @@ -3376,6 +3376,7 @@ namespace ts {
}

/* @internal */
/** Syntax maps to property names like so: { [typeParameter in constraintType]: templateType } */
export interface MappedType extends AnonymousType {
declaration: MappedTypeNode;
typeParameter?: TypeParameter;
Expand Down
17 changes: 9 additions & 8 deletions tests/baselines/reference/mappedTypeErrors.errors.txt
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(19,20): error TS2313: Type parameter 'P' has a circular constraint.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(20,20): error TS2322: Type 'number' is not assignable to type 'string'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(21,20): error TS2322: Type 'Date' is not assignable to type 'string'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(21,20): error TS2322: Type 'Date' is not assignable to type 'string | number'.
Type 'Date' is not assignable to type 'number'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(22,19): error TS2344: Type 'Date' does not satisfy the constraint 'string'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(25,24): error TS2344: Type '"foo"' does not satisfy the constraint '"name" | "width" | "height" | "visible"'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(26,24): error TS2344: Type '"name" | "foo"' does not satisfy the constraint '"name" | "width" | "height" | "visible"'.
Expand Down Expand Up @@ -45,11 +45,12 @@ tests/cases/conformance/types/mapped/mappedTypeErrors.ts(129,5): error TS2322: T
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(130,5): error TS2322: Type '{ a: string; }' is not assignable to type '{ [x: string]: any; a?: number | undefined; }'.
Types of property 'a' are incompatible.
Type 'string' is not assignable to type 'number | undefined'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,16): error TS2322: Type 'T' is not assignable to type 'string'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,16): error TS2322: Type 'T' is not assignable to type 'string | number'.
Type 'T' is not assignable to type 'number'.
tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,21): error TS2536: Type 'P' cannot be used to index type 'T'.


==== tests/cases/conformance/types/mapped/mappedTypeErrors.ts (26 errors) ====
==== tests/cases/conformance/types/mapped/mappedTypeErrors.ts (25 errors) ====
interface Shape {
name: string;
width: number;
Expand All @@ -72,11 +73,10 @@ tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,21): error TS2536:
~
!!! error TS2313: Type parameter 'P' has a circular constraint.
type T01 = { [P in number]: string }; // Error
~~~~~~
!!! error TS2322: Type 'number' is not assignable to type 'string'.
type T02 = { [P in Date]: number }; // Error
~~~~
!!! error TS2322: Type 'Date' is not assignable to type 'string'.
!!! error TS2322: Type 'Date' is not assignable to type 'string | number'.
!!! error TS2322: Type 'Date' is not assignable to type 'number'.
type T03 = Record<Date, number>; // Error
~~~~
!!! error TS2344: Type 'Date' does not satisfy the constraint 'string'.
Expand Down Expand Up @@ -258,7 +258,8 @@ tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,21): error TS2536:
pf: {[P in F]?: T[P]},
pt: {[P in T]?: T[P]}, // note: should be in keyof T
~
!!! error TS2322: Type 'T' is not assignable to type 'string'.
!!! error TS2322: Type 'T' is not assignable to type 'string | number'.
!!! error TS2322: Type 'T' is not assignable to type 'number'.
~~~~
!!! error TS2536: Type 'P' cannot be used to index type 'T'.
};
Expand Down
127 changes: 127 additions & 0 deletions tests/baselines/reference/mappedTypeNumericEnum.errors.txt
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@@ -0,0 +1,127 @@
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(13,35): error TS2322: Type '{ '0': true; '2': boolean; }' is not assignable to type 'NumBool'.
Object literal may only specify known properties, and ''2'' does not exist in type 'NumBool'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(14,5): error TS2322: Type '{ '0': true; }' is not assignable to type 'NumBool'.
Property '"1"' is missing in type '{ '0': true; }'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(17,1): error TS7017: Element implicitly has an 'any' type because type 'NumBool' has no index signature.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(27,1): error TS7017: Element implicitly has an 'any' type because type 'StrAny' has no index signature.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(33,49): error TS2322: Type '{ '0': number; [Nums.B]: number; [Nums2.Gimel]: number; }' is not assignable to type 'NumNum'.
Object literal may only specify known properties, and '[Nums2.Gimel]' does not exist in type 'NumNum'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(41,40): error TS2322: Type '{ [Nums.A]: number; [Nums.B]: number; }' is not assignable to type 'OneNumNum'.
Object literal may only specify known properties, and '[Nums.B]' does not exist in type 'OneNumNum'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(44,1): error TS7017: Element implicitly has an 'any' type because type 'OneNumNum' has no index signature.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(50,6): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(51,6): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(63,4): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(69,5): error TS2322: Type '{ [0]: number; [1]: number; }' is not assignable to type 'MixNum'.
Property 'a' is missing in type '{ [0]: number; [1]: number; }'.
tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts(75,30): error TS2322: Type '{ [0]: number; [1]: number; [2]: number; }' is not assignable to type 'MixConflictNum'.
Object literal may only specify known properties, and '[0]' does not exist in type 'MixConflictNum'.


==== tests/cases/conformance/types/mapped/mappedTypeNumericEnum.ts (12 errors) ====
// with numbers
enum Nums {
A,
B
}
enum Nums2 {
Aleph,
Bet,
Gimel
}
type NumBool = { [K in Nums]: boolean }
let nb: NumBool = { '0': true, '1': false }
let wronb: NumBool = { '0': true, '2': false }
~~~~~~~~~~
!!! error TS2322: Type '{ '0': true; '2': boolean; }' is not assignable to type 'NumBool'.
!!! error TS2322: Object literal may only specify known properties, and ''2'' does not exist in type 'NumBool'.
let wronb2: NumBool = { '0': true }
~~~~~~
!!! error TS2322: Type '{ '0': true; }' is not assignable to type 'NumBool'.
!!! error TS2322: Property '"1"' is missing in type '{ '0': true; }'.
nb[Nums.A] = false;
nb[Nums2.Bet] = true;
nb[Nums2.Gimel] = false; // only disallowed with --strict
~~~~~~~~~~~~~~~
!!! error TS7017: Element implicitly has an 'any' type because type 'NumBool' has no index signature.

// with strings
enum Strs {
A = 'a',
B = 'b'
}
type StrAny = { [K in Strs]: any }
let sa: StrAny = { a: 1, b: 2 }
sa[Strs.A] = 'a'
sa['nope'] = 'not allowed'
~~~~~~~~~~
!!! error TS7017: Element implicitly has an 'any' type because type 'StrAny' has no index signature.

// union of numbers
type Ns = 0 | 1;
type NumNum = { [K in Ns]: number }
let nn: NumNum = { [Nums.A]: 3, [Nums.B]: 4 }
let omnomnom: NumNum = { '0': 12, [Nums.B]: 13, [Nums2.Gimel]: 14 }
~~~~~~~~~~~~~~~~~
!!! error TS2322: Type '{ '0': number; [Nums.B]: number; [Nums2.Gimel]: number; }' is not assignable to type 'NumNum'.
!!! error TS2322: Object literal may only specify known properties, and '[Nums2.Gimel]' does not exist in type 'NumNum'.
nn[0] = 5
nn['1'] = 6

// single number
type N = 0;
type OneNumNum = { [K in N]: number }
let onn: OneNumNum = { [Nums.A]: 7 }
let wronng: OneNumNum = { [Nums.A]: 7, [Nums.B]: 11 }
~~~~~~~~~~~~
!!! error TS2322: Type '{ [Nums.A]: number; [Nums.B]: number; }' is not assignable to type 'OneNumNum'.
!!! error TS2322: Object literal may only specify known properties, and '[Nums.B]' does not exist in type 'OneNumNum'.
onn[0] = 8
onn['0'] = 9
onn[1] = 10 // only disallowed with --strict
~~~~~~
!!! error TS7017: Element implicitly has an 'any' type because type 'OneNumNum' has no index signature.

// just number
type NumberNum = { [K in number]: number }
let numn: NumberNum = { }
numn[0] = 31
numn['1'] = 32
~~~
!!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
numn['oops'] = 33
~~~~~~
!!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.

// computed enum gets a string indexer
enum Comp {
A,
B = 1 << 3
}

type CompNum = { [K in Comp]: number }
let cn: CompNum = { [Comp.A]: 15 }
let cnn: CompNum = { [Comp.A]: 16, '101': 17 }
cn[1001] = 18
cn['maybe?'] = 19
~~~~~~~~
!!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.

// manual string/number union mixes
type Mix = 0 | 1 | 'a' | 'i' | 'u';
type MixNum = { [K in Mix]: number }
let mn: MixNum = { [0]: 20, '1': 21, a: 22, i: 23, u: 24 }
let mnn: MixNum = { [0]: 29, [1]: 30 }
~~~
!!! error TS2322: Type '{ [0]: number; [1]: number; }' is not assignable to type 'MixNum'.
!!! error TS2322: Property 'a' is missing in type '{ [0]: number; [1]: number; }'.

// conflicts result in the property being thrown out
type MixConflict = 0 | 1 | 1 | 1 | 1 | 1 | 2 | '0' | '1';
type MixConflictNum = { [K in MixConflict]: number }
let mcn: MixConflictNum = { [2]: 25 }
let mcnn: MixConflictNum = { [0]: 26, [1]: 27, [2]: 28 }
~~~~~~~
!!! error TS2322: Type '{ [0]: number; [1]: number; [2]: number; }' is not assignable to type 'MixConflictNum'.
!!! error TS2322: Object literal may only specify known properties, and '[0]' does not exist in type 'MixConflictNum'.

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