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Filter out nullable and primitive types in isDiscriminantProperty

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This commit is contained in:
Anders Hejlsberg 2016-08-11 13:46:06 -07:00
parent a3845a95d5
commit c22a54fb95
1 changed files with 21 additions and 13 deletions
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34
src/compiler/checker.ts
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@ -245,7 +245,8 @@ namespace ts {
NEUndefinedOrNull = 1 << 19, // x != undefined / x != null
Truthy = 1 << 20, // x
Falsy = 1 << 21, // !x
All = (1 << 22) - 1,
Discriminatable = 1 << 22, // May have discriminant property
All = (1 << 23) - 1,
// The following members encode facts about particular kinds of types for use in the getTypeFacts function.
// The presence of a particular fact means that the given test is true for some (and possibly all) values
// of that kind of type.
@ -275,9 +276,9 @@ namespace ts {
TrueFacts = BaseBooleanFacts | Truthy,
SymbolStrictFacts = TypeofEQSymbol | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | NEUndefined | NENull | NEUndefinedOrNull | Truthy,
SymbolFacts = SymbolStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
ObjectStrictFacts = TypeofEQObject | TypeofEQHostObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | NEUndefined | NENull | NEUndefinedOrNull | Truthy,
ObjectStrictFacts = TypeofEQObject | TypeofEQHostObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | NEUndefined | NENull | NEUndefinedOrNull | Truthy | Discriminatable,
ObjectFacts = ObjectStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
FunctionStrictFacts = TypeofEQFunction | TypeofEQHostObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | NEUndefined | NENull | NEUndefinedOrNull | Truthy,
FunctionStrictFacts = TypeofEQFunction | TypeofEQHostObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | NEUndefined | NENull | NEUndefinedOrNull | Truthy | Discriminatable,
FunctionFacts = FunctionStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
UndefinedFacts = TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | EQUndefined | EQUndefinedOrNull | NENull | Falsy,
NullFacts = TypeofEQObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | TypeofNEHostObject | EQNull | EQUndefinedOrNull | NEUndefined | Falsy,
@ -7848,18 +7849,25 @@ namespace ts {
}
function isDiscriminantProperty(type: Type, name: string) {
if (type) {
const nonNullType = getNonNullableType(type);
if (nonNullType.flags & TypeFlags.Union) {
const prop = getPropertyOfType(nonNullType, name);
if (prop && prop.flags & SymbolFlags.SyntheticProperty) {
if ((<TransientSymbol>prop).isDiscriminantProperty === undefined) {
(<TransientSymbol>prop).isDiscriminantProperty = !(<TransientSymbol>prop).hasCommonType &&
isUnitUnionType(getTypeOfSymbol(prop));
}
return (<TransientSymbol>prop).isDiscriminantProperty;
if (type && type.flags & TypeFlags.Union) {
let prop = getPropertyOfType(type, name);
if (!prop) {
// The type may be a union that includes nullable or primtive types. If filtering
// those out produces a different type, get the property from that type instead.
// Effectively, we're checking if this *could* be a discriminant property once nullable
// and primitive types are removed by other type guards.
const filteredType = getTypeWithFacts(type, TypeFacts.Discriminatable);
if (filteredType !== type && filteredType.flags & TypeFlags.Union) {
prop = getPropertyOfType(type, name);
}
}
if (prop && prop.flags & SymbolFlags.SyntheticProperty) {
if ((<TransientSymbol>prop).isDiscriminantProperty === undefined) {
(<TransientSymbol>prop).isDiscriminantProperty = !(<TransientSymbol>prop).hasCommonType &&
isUnitUnionType(getTypeOfSymbol(prop));
}
return (<TransientSymbol>prop).isDiscriminantProperty;
}
}
return false;
}