maxmustermann/TypeScript
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

Fix NarrowTypeByTypeof, NarrowTypeByInstanceof, isPropertyInitializedInConstructor

Browse source
This commit is contained in:
Anders Hejlsberg 2019-02-03 08:19:22 -08:00
parent 0a041ee536
commit 343e0f7fd9
1 changed files with 7 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
src/compiler/checker.ts
View file

@ -15045,11 +15045,6 @@ namespace ts {
return false;
}
function hasNarrowableDeclaredType(expr: Node) {
const type = getDeclaredTypeOfReference(expr);
return !!(type && type.flags & TypeFlags.Union);
}
function findDiscriminantProperties(sourceProperties: Symbol[], target: Type): Symbol[] | undefined {
let result: Symbol[] | undefined;
for (const sourceProperty of sourceProperties) {
@ -16107,9 +16102,9 @@ namespace ts {
// We have '==', '!=', '====', or !==' operator with 'typeof xxx' and string literal operands
const target = getReferenceCandidate(typeOfExpr.expression);
if (!isMatchingReference(reference, target)) {
// For a reference of the form 'x.y', where 'x' has a narrowable declared type, a
// 'typeof x === ...' type guard resets the narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, target) && hasNarrowableDeclaredType(target)) {
// For a reference of the form 'x.y', a 'typeof x === ...' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, target)) {
return declaredType;
}
return type;
@ -16264,9 +16259,9 @@ namespace ts {
function narrowTypeByInstanceof(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
const left = getReferenceCandidate(expr.left);
if (!isMatchingReference(reference, left)) {
// For a reference of the form 'x.y', where 'x' has a narrowable declared type, an
// 'x instanceof T' type guard resets the narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, left) && hasNarrowableDeclaredType(left)) {
// For a reference of the form 'x.y', an 'x instanceof T' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, left)) {
return declaredType;
}
return type;
@ -27221,7 +27216,7 @@ namespace ts {
reference.expression.parent = reference;
reference.parent = constructor;
reference.flowNode = constructor.returnFlowNode;
const flowType = getFlowTypeOfReference(reference, propType, getOptionalType(propType));
const flowType = getFlowTypeOfReference(reference, getOptionalType(propType));
return !(getFalsyFlags(flowType) & TypeFlags.Undefined);
}