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narrow from 'any' in most situations

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instanceof and user-defined typeguards narrow from 'any' unless the narrowed-to type is exactly 'Object' or 'Function'. This is a breaking change.
This commit is contained in:
yortus 2016-08-13 13:57:18 +08:00
parent 10d1e02916
commit 38353027aa
1 changed files with 12 additions and 5 deletions
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17
src/compiler/checker.ts
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@ -8548,10 +8548,6 @@ namespace ts {
}
return type;
}
// We never narrow type any in an instanceof guard
if (isTypeAny(type)) {
return type;
}
// Check that right operand is a function type with a prototype property
const rightType = checkExpression(expr.right);
@ -8569,6 +8565,11 @@ namespace ts {
}
}
// Don't narrow from 'any' if the target type is exactly 'Object' or 'Function'
if (isTypeAny(type) && (targetType === globalObjectType || targetType === globalFunctionType)) {
return type;
}
if (!targetType) {
// Target type is type of construct signature
let constructSignatures: Signature[];
@ -8615,7 +8616,7 @@ namespace ts {
}
function narrowTypeByTypePredicate(type: Type, callExpression: CallExpression, assumeTrue: boolean): Type {
if (type.flags & TypeFlags.Any || !hasMatchingArgument(callExpression, reference)) {
if (!hasMatchingArgument(callExpression, reference)) {
return type;
}
const signature = getResolvedSignature(callExpression);
@ -8623,6 +8624,12 @@ namespace ts {
if (!predicate) {
return type;
}
// Don't narrow from 'any' if the predicate type is exactly 'Object' or 'Function'
if (isTypeAny(type) && (predicate.type === globalObjectType || predicate.type === globalFunctionType)) {
return type;
}
if (isIdentifierTypePredicate(predicate)) {
const predicateArgument = callExpression.arguments[predicate.parameterIndex];
if (predicateArgument) {