microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-05-17 21:06:50 -05:00
Code Issues Packages Projects Releases 212 Wiki Activity

Infer over each mapped type constraint member if it is a union (#28006)

Browse Source
This commit is contained in:
Wesley Wigham
2018-10-22 16:33:43 -07:00
committed by GitHub
parent 68ce68da79
commit f701daf4e0
6 changed files with 182 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

88
src/compiler/checker.ts
View File

@@ -6786,7 +6786,7 @@ namespace ts {
const modifiers = getMappedTypeModifiers(type.mappedType);
const readonlyMask = modifiers & MappedTypeModifiers.IncludeReadonly ? false : true;
const optionalMask = modifiers & MappedTypeModifiers.IncludeOptional ? 0 : SymbolFlags.Optional;
const stringIndexInfo = indexInfo && createIndexInfo(inferReverseMappedType(indexInfo.type, type.mappedType), readonlyMask && indexInfo.isReadonly);
const stringIndexInfo = indexInfo && createIndexInfo(inferReverseMappedType(indexInfo.type, type.mappedType, type.constraintType), readonlyMask && indexInfo.isReadonly);
const members = createSymbolTable();
for (const prop of getPropertiesOfType(type.source)) {
const checkFlags = CheckFlags.ReverseMapped | (readonlyMask && isReadonlySymbol(prop) ? CheckFlags.Readonly : 0);
@@ -6795,6 +6795,7 @@ namespace ts {
inferredProp.nameType = prop.nameType;
inferredProp.propertyType = getTypeOfSymbol(prop);
inferredProp.mappedType = type.mappedType;
inferredProp.constraintType = type.constraintType;
members.set(prop.escapedName, inferredProp);
}
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, undefined);
@@ -13493,18 +13494,18 @@ namespace ts {
* property is computed by inferring from the source property type to X for the type
* variable T[P] (i.e. we treat the type T[P] as the type variable we're inferring for).
*/
function inferTypeForHomomorphicMappedType(source: Type, target: MappedType): Type | undefined {
const key = source.id + "," + target.id;
function inferTypeForHomomorphicMappedType(source: Type, target: MappedType, constraint: IndexType): Type | undefined {
const key = source.id + "," + target.id + "," + constraint.id;
if (reverseMappedCache.has(key)) {
return reverseMappedCache.get(key);
}
reverseMappedCache.set(key, undefined);
const type = createReverseMappedType(source, target);
const type = createReverseMappedType(source, target, constraint);
reverseMappedCache.set(key, type);
return type;
}
function createReverseMappedType(source: Type, target: MappedType) {
function createReverseMappedType(source: Type, target: MappedType, constraint: IndexType) {
const properties = getPropertiesOfType(source);
if (properties.length === 0 && !getIndexInfoOfType(source, IndexKind.String)) {
return undefined;
@@ -13519,13 +13520,13 @@ namespace ts {
// For arrays and tuples we infer new arrays and tuples where the reverse mapping has been
// applied to the element type(s).
if (isArrayType(source)) {
return createArrayType(inferReverseMappedType((<TypeReference>source).typeArguments![0], target));
return createArrayType(inferReverseMappedType((<TypeReference>source).typeArguments![0], target, constraint));
}
if (isReadonlyArrayType(source)) {
return createReadonlyArrayType(inferReverseMappedType((<TypeReference>source).typeArguments![0], target));
return createReadonlyArrayType(inferReverseMappedType((<TypeReference>source).typeArguments![0], target, constraint));
}
if (isTupleType(source)) {
const elementTypes = map(source.typeArguments || emptyArray, t => inferReverseMappedType(t, target));
const elementTypes = map(source.typeArguments || emptyArray, t => inferReverseMappedType(t, target, constraint));
const minLength = getMappedTypeModifiers(target) & MappedTypeModifiers.IncludeOptional ?
getTypeReferenceArity(source) - (source.target.hasRestElement ? 1 : 0) : source.target.minLength;
return createTupleType(elementTypes, minLength, source.target.hasRestElement, source.target.associatedNames);
@@ -13535,15 +13536,16 @@ namespace ts {
const reversed = createObjectType(ObjectFlags.ReverseMapped | ObjectFlags.Anonymous, /*symbol*/ undefined) as ReverseMappedType;
reversed.source = source;
reversed.mappedType = target;
reversed.constraintType = constraint;
return reversed;
}
function getTypeOfReverseMappedSymbol(symbol: ReverseMappedSymbol) {
return inferReverseMappedType(symbol.propertyType, symbol.mappedType);
return inferReverseMappedType(symbol.propertyType, symbol.mappedType, symbol.constraintType);
}
function inferReverseMappedType(sourceType: Type, target: MappedType): Type {
const typeParameter = <TypeParameter>getIndexedAccessType((<IndexType>getConstraintTypeFromMappedType(target)).type, getTypeParameterFromMappedType(target));
function inferReverseMappedType(sourceType: Type, target: MappedType, constraint: IndexType): Type {
const typeParameter = <TypeParameter>getIndexedAccessType(constraint.type, getTypeParameterFromMappedType(target));
const templateType = getTemplateTypeFromMappedType(target);
const inference = createInferenceInfo(typeParameter);
inferTypes([inference], sourceType, templateType);
@@ -13841,6 +13843,44 @@ namespace ts {
return undefined;
}
function inferFromMappedTypeConstraint(source: Type, target: Type, constraintType: Type): boolean {
if (constraintType.flags & TypeFlags.Union) {
let result = false;
for (const type of (constraintType as UnionType).types) {
result = inferFromMappedTypeConstraint(source, target, type) || result;
}
return result;
}
if (constraintType.flags & TypeFlags.Index) {
// We're inferring from some source type S to a homomorphic mapped type { [P in keyof T]: X },
// where T is a type variable. Use inferTypeForHomomorphicMappedType to infer a suitable source
// type and then make a secondary inference from that type to T. We make a secondary inference
// such that direct inferences to T get priority over inferences to Partial<T>, for example.
const inference = getInferenceInfoForType((<IndexType>constraintType).type);
if (inference && !inference.isFixed) {
const inferredType = inferTypeForHomomorphicMappedType(source, <MappedType>target, constraintType as IndexType);
if (inferredType) {
const savePriority = priority;
priority |= InferencePriority.HomomorphicMappedType;
inferFromTypes(inferredType, inference.typeParameter);
priority = savePriority;
}
}
return true;
}
if (constraintType.flags & TypeFlags.TypeParameter) {
// We're inferring from some source type S to a mapped type { [P in T]: X }, where T is a type
// parameter. Infer from 'keyof S' to T and infer from a union of each property type in S to X.
const savePriority = priority;
priority |= InferencePriority.MappedTypeConstraint;
inferFromTypes(getIndexType(source), constraintType);
priority = savePriority;
inferFromTypes(getUnionType(map(getPropertiesOfType(source), getTypeOfSymbol)), getTemplateTypeFromMappedType(<MappedType>target));
return true;
}
return false;
}
function inferFromObjectTypes(source: Type, target: Type) {
if (isGenericMappedType(source) && isGenericMappedType(target)) {
// The source and target types are generic types { [P in S]: X } and { [P in T]: Y }, so we infer
@@ -13850,31 +13890,7 @@ namespace ts {
}
if (getObjectFlags(target) & ObjectFlags.Mapped) {
const constraintType = getConstraintTypeFromMappedType(<MappedType>target);
if (constraintType.flags & TypeFlags.Index) {
// We're inferring from some source type S to a homomorphic mapped type { [P in keyof T]: X },
// where T is a type variable. Use inferTypeForHomomorphicMappedType to infer a suitable source
// type and then make a secondary inference from that type to T. We make a secondary inference
// such that direct inferences to T get priority over inferences to Partial<T>, for example.
const inference = getInferenceInfoForType((<IndexType>constraintType).type);
if (inference && !inference.isFixed) {
const inferredType = inferTypeForHomomorphicMappedType(source, <MappedType>target);
if (inferredType) {
const savePriority = priority;
priority |= InferencePriority.HomomorphicMappedType;
inferFromTypes(inferredType, inference.typeParameter);
priority = savePriority;
}
}
return;
}
if (constraintType.flags & TypeFlags.TypeParameter) {
// We're inferring from some source type S to a mapped type { [P in T]: X }, where T is a type
// parameter. Infer from 'keyof S' to T and infer from a union of each property type in S to X.
const savePriority = priority;
priority |= InferencePriority.MappedTypeConstraint;
inferFromTypes(getIndexType(source), constraintType);
priority = savePriority;
inferFromTypes(getUnionType(map(getPropertiesOfType(source), getTypeOfSymbol)), getTemplateTypeFromMappedType(<MappedType>target));
if (inferFromMappedTypeConstraint(source, target, constraintType)) {
return;
}
}

2
src/compiler/types.ts
View File

@@ -3682,6 +3682,7 @@ namespace ts {
export interface ReverseMappedSymbol extends TransientSymbol {
propertyType: Type;
mappedType: MappedType;
constraintType: IndexType;
}
export const enum InternalSymbolName {
@@ -4090,6 +4091,7 @@ namespace ts {
export interface ReverseMappedType extends ObjectType {
source: Type;
mappedType: MappedType;
constraintType: IndexType;
}
/* @internal */