microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-05-30 01:04:49 -05:00
Code Issues Packages Projects Releases 212 Wiki Activity

Restoring union type subtype reduction

Browse Source
This commit is contained in:
Anders Hejlsberg
2015-08-28 14:50:58 -07:00
parent 59782a98eb
commit d8d7fb96b5
1 changed files with 44 additions and 94 deletions
Download Patch File Download Diff File Expand all files Collapse all files

138
src/compiler/checker.ts
View File

@@ -3119,7 +3119,7 @@ namespace ts {
}
function resolveTupleTypeMembers(type: TupleType) {
let arrayType = resolveStructuredTypeMembers(createArrayType(getUnionType(type.elementTypes, /*noDeduplication*/ true)));
let arrayType = resolveStructuredTypeMembers(createArrayType(getUnionType(type.elementTypes, /*noSubtypeReduction*/ true)));
let members = createTupleTypeMemberSymbols(type.elementTypes);
addInheritedMembers(members, arrayType.properties);
setObjectTypeMembers(type, members, arrayType.callSignatures, arrayType.constructSignatures, arrayType.stringIndexType, arrayType.numberIndexType);
@@ -3451,29 +3451,6 @@ namespace ts {
return undefined;
}
// Check if a property with the given name is known anywhere in the given type. In an object
// type, a property is considered known if the object type is empty, if it has any index
// signatures, or if the property is actually declared in the type. In a union or intersection
// type, a property is considered known if it is known in any constituent type.
function isKnownProperty(type: Type, name: string): boolean {
if (type.flags & TypeFlags.ObjectType && type !== globalObjectType) {
const resolved = resolveStructuredTypeMembers(type);
return !!(resolved.properties.length === 0 ||
resolved.stringIndexType ||
resolved.numberIndexType ||
getPropertyOfType(type, name));
}
if (type.flags & TypeFlags.UnionOrIntersection) {
for (let t of (<UnionOrIntersectionType>type).types) {
if (isKnownProperty(t, name)) {
return true;
}
}
return false;
}
return true;
}
function getSignaturesOfStructuredType(type: Type, kind: SignatureKind): Signature[] {
if (type.flags & TypeFlags.StructuredType) {
let resolved = resolveStructuredTypeMembers(<ObjectType>type);
@@ -4103,73 +4080,20 @@ namespace ts {
}
}
function isObjectLiteralTypeDuplicateOf(source: ObjectType, target: ObjectType): boolean {
let sourceProperties = getPropertiesOfObjectType(source);
let targetProperties = getPropertiesOfObjectType(target);
if (sourceProperties.length !== targetProperties.length) {
return false;
}
for (let sourceProp of sourceProperties) {
let targetProp = getPropertyOfObjectType(target, sourceProp.name);
if (!targetProp ||
getDeclarationFlagsFromSymbol(targetProp) & (NodeFlags.Private | NodeFlags.Protected) ||
!isTypeDuplicateOf(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp))) {
return false;
}
}
return true;
}
function isTupleTypeDuplicateOf(source: TupleType, target: TupleType): boolean {
let sourceTypes = source.elementTypes;
let targetTypes = target.elementTypes;
if (sourceTypes.length !== targetTypes.length) {
return false;
}
for (var i = 0; i < sourceTypes.length; i++) {
if (!isTypeDuplicateOf(sourceTypes[i], targetTypes[i])) {
return false;
}
}
return true;
}
// Returns true if the source type is a duplicate of the target type. A source type is a duplicate of
// a target type if the the two are identical, with the exception that the source type may have null or
// undefined in places where the target type doesn't. This is by design an asymmetric relationship.
function isTypeDuplicateOf(source: Type, target: Type): boolean {
if (source === target) {
return true;
}
if (source.flags & TypeFlags.Undefined || source.flags & TypeFlags.Null && !(target.flags & TypeFlags.Undefined)) {
return true;
}
if (source.flags & TypeFlags.ObjectLiteral && target.flags & TypeFlags.ObjectType) {
return isObjectLiteralTypeDuplicateOf(<ObjectType>source, <ObjectType>target);
}
if (isArrayType(source) && isArrayType(target)) {
return isTypeDuplicateOf((<TypeReference>source).typeArguments[0], (<TypeReference>target).typeArguments[0]);
}
if (isTupleType(source) && isTupleType(target)) {
return isTupleTypeDuplicateOf(<TupleType>source, <TupleType>target);
}
return isTypeIdenticalTo(source, target);
}
function isTypeDuplicateOfSomeType(candidate: Type, types: Type[]): boolean {
for (let type of types) {
if (candidate !== type && isTypeDuplicateOf(candidate, type)) {
function isSubtypeOfAny(candidate: Type, types: Type[]): boolean {
for (var i = 0, len = types.length; i < len; i++) {
if (candidate !== types[i] && isTypeSubtypeOf(candidate, types[i])) {
return true;
}
}
return false;
}
function removeDuplicateTypes(types: Type[]) {
let i = types.length;
function removeSubtypes(types: Type[]) {
var i = types.length;
while (i > 0) {
i--;
if (isTypeDuplicateOfSomeType(types[i], types)) {
if (isSubtypeOfAny(types[i], types)) {
types.splice(i, 1);
}
}
@@ -4194,12 +4118,14 @@ namespace ts {
}
}
// We always deduplicate the constituent type set based on object identity, but we'll also deduplicate
// based on the structure of the types unless the noDeduplication flag is true, which is the case when
// creating a union type from a type node and when instantiating a union type. In both of those cases,
// structural deduplication has to be deferred to properly support recursive union types. For example,
// a type of the form "type Item = string | (() => Item)" cannot be deduplicated during its declaration.
function getUnionType(types: Type[], noDeduplication?: boolean): Type {
// We reduce the constituent type set to only include types that aren't subtypes of other types, unless
// the noSubtypeReduction flag is specified, in which case we perform a simple deduplication based on
// object identity. Subtype reduction is possible only when union types are known not to circularly
// reference themselves (as is the case with union types created by expression constructs such as array
// literals and the || and ?: operators). Named types can circularly reference themselves and therefore
// cannot be deduplicated during their declaration. For example, "type Item = string | (() => Item" is
// a named type that circularly references itself.
function getUnionType(types: Type[], noSubtypeReduction?: boolean): Type {
if (types.length === 0) {
return emptyObjectType;
}
@@ -4208,12 +4134,12 @@ namespace ts {
if (containsTypeAny(typeSet)) {
return anyType;
}
if (noDeduplication) {
if (noSubtypeReduction) {
removeAllButLast(typeSet, undefinedType);
removeAllButLast(typeSet, nullType);
}
else {
removeDuplicateTypes(typeSet);
removeSubtypes(typeSet);
}
if (typeSet.length === 1) {
return typeSet[0];
@@ -4230,7 +4156,7 @@ namespace ts {
function getTypeFromUnionTypeNode(node: UnionTypeNode): Type {
let links = getNodeLinks(node);
if (!links.resolvedType) {
links.resolvedType = getUnionType(map(node.types, getTypeFromTypeNode), /*noDeduplication*/ true);
links.resolvedType = getUnionType(map(node.types, getTypeFromTypeNode), /*noSubtypeReduction*/ true);
}
return links.resolvedType;
}
@@ -4526,7 +4452,7 @@ namespace ts {
return createTupleType(instantiateList((<TupleType>type).elementTypes, mapper, instantiateType));
}
if (type.flags & TypeFlags.Union) {
return getUnionType(instantiateList((<UnionType>type).types, mapper, instantiateType), /*noDeduplication*/ true);
return getUnionType(instantiateList((<UnionType>type).types, mapper, instantiateType), /*noSubtypeReduction*/ true);
}
if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType));
@@ -4813,6 +4739,30 @@ namespace ts {
return Ternary.False;
}
// Check if a property with the given name is known anywhere in the given type. In an object type, a property
// is considered known if the object type is empty and the check is for assignability, if the object type has
// index signatures, or if the property is actually declared in the object type. In a union or intersection
// type, a property is considered known if it is known in any constituent type.
function isKnownProperty(type: Type, name: string): boolean {
if (type.flags & TypeFlags.ObjectType) {
const resolved = resolveStructuredTypeMembers(type);
if (relation === assignableRelation && (type === globalObjectType || resolved.properties.length === 0) ||
resolved.stringIndexType || resolved.numberIndexType || getPropertyOfType(type, name)) {
return true;
}
return false;
}
if (type.flags & TypeFlags.UnionOrIntersection) {
for (let t of (<UnionOrIntersectionType>type).types) {
if (isKnownProperty(t, name)) {
return true;
}
}
return false;
}
return true;
}
function hasExcessProperties(source: FreshObjectLiteralType, target: Type, reportErrors: boolean): boolean {
for (let prop of getPropertiesOfObjectType(source)) {
if (!isKnownProperty(target, prop.name)) {
@@ -5594,7 +5544,7 @@ namespace ts {
return getWidenedTypeOfObjectLiteral(type);
}
if (type.flags & TypeFlags.Union) {
return getUnionType(map((<UnionType>type).types, getWidenedType));
return getUnionType(map((<UnionType>type).types, getWidenedType), /*noSubtypeReduction*/ true);
}
if (isArrayType(type)) {
return createArrayType(getWidenedType((<TypeReference>type).typeArguments[0]));