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No widening of 'null' and 'undefined' types in --strictNullChecks mode

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This commit is contained in:
Anders Hejlsberg 2016-03-04 10:42:23 -08:00
parent 87ae0489eb
commit c623e1f8c9
1 changed files with 32 additions and 15 deletions
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47
src/compiler/checker.ts
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@ -107,14 +107,15 @@ namespace ts {
const unknownSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, "unknown");
const resolvingSymbol = createSymbol(SymbolFlags.Transient, "__resolving__");
const nullableWideningFlags = strictNullChecks ? 0 : TypeFlags.ContainsUndefinedOrNull;
const anyType = createIntrinsicType(TypeFlags.Any, "any");
const stringType = createIntrinsicType(TypeFlags.String, "string");
const numberType = createIntrinsicType(TypeFlags.Number, "number");
const booleanType = createIntrinsicType(TypeFlags.Boolean, "boolean");
const esSymbolType = createIntrinsicType(TypeFlags.ESSymbol, "symbol");
const voidType = createIntrinsicType(TypeFlags.Void, "void");
const undefinedType = createIntrinsicType(TypeFlags.Undefined | TypeFlags.ContainsUndefinedOrNull, "undefined");
const nullType = createIntrinsicType(TypeFlags.Null | TypeFlags.ContainsUndefinedOrNull, "null");
const undefinedType = createIntrinsicType(TypeFlags.Undefined | nullableWideningFlags, "undefined");
const nullType = createIntrinsicType(TypeFlags.Null | nullableWideningFlags, "null");
const emptyArrayElementType = createIntrinsicType(TypeFlags.Undefined | TypeFlags.ContainsUndefinedOrNull, "undefined");
const unknownType = createIntrinsicType(TypeFlags.Any, "unknown");
@ -4719,10 +4720,21 @@ namespace ts {
return links.resolvedType;
}
function addTypeToSet(typeSet: Type[], type: Type, typeSetKind: TypeFlags) {
interface TypeSet extends Array<Type> {
containsAny?: boolean;
containsUndefined?: boolean;
containsNull?: boolean;
}
function addTypeToSet(typeSet: TypeSet, type: Type, typeSetKind: TypeFlags) {
if (type.flags & typeSetKind) {
addTypesToSet(typeSet, (<UnionOrIntersectionType>type).types, typeSetKind);
}
else if (type.flags & (TypeFlags.Any | TypeFlags.Undefined | TypeFlags.Null)) {
if (type.flags & TypeFlags.Any) typeSet.containsAny = true;
if (type.flags & TypeFlags.Undefined) typeSet.containsUndefined = true;
if (type.flags & TypeFlags.Null) typeSet.containsNull = true;
}
else if (!contains(typeSet, type)) {
typeSet.push(type);
}
@ -4730,7 +4742,7 @@ namespace ts {
// Add the given types to the given type set. Order is preserved, duplicates are removed,
// and nested types of the given kind are flattened into the set.
function addTypesToSet(typeSet: Type[], types: Type[], typeSetKind: TypeFlags) {
function addTypesToSet(typeSet: TypeSet, types: Type[], typeSetKind: TypeFlags) {
for (const type of types) {
addTypeToSet(typeSet, type, typeSetKind);
}
@ -4785,21 +4797,22 @@ namespace ts {
if (types.length === 0) {
return emptyUnionType;
}
const typeSet: Type[] = [];
const typeSet = [] as TypeSet;
addTypesToSet(typeSet, types, TypeFlags.Union);
if (containsTypeAny(typeSet)) {
if (typeSet.containsAny) {
return anyType;
}
if (noSubtypeReduction) {
if (!strictNullChecks) {
removeAllButLast(typeSet, undefinedType);
removeAllButLast(typeSet, nullType);
}
if (strictNullChecks) {
if (typeSet.containsNull) typeSet.push(nullType);
if (typeSet.containsUndefined) typeSet.push(undefinedType);
}
else {
if (!noSubtypeReduction) {
removeSubtypes(typeSet);
}
if (typeSet.length === 1) {
if (typeSet.length === 0) {
return typeSet.containsNull ? nullType : undefinedType;
}
else if (typeSet.length === 1) {
return typeSet[0];
}
const id = getTypeListId(typeSet);
@ -4829,11 +4842,15 @@ namespace ts {
if (types.length === 0) {
return emptyObjectType;
}
const typeSet: Type[] = [];
const typeSet = [] as TypeSet;
addTypesToSet(typeSet, types, TypeFlags.Intersection);
if (containsTypeAny(typeSet)) {
if (typeSet.containsAny) {
return anyType;
}
if (strictNullChecks) {
if (typeSet.containsNull) typeSet.push(nullType);
if (typeSet.containsUndefined) typeSet.push(undefinedType);
}
if (typeSet.length === 1) {
return typeSet[0];
}