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

PR feedback

Browse source
This commit is contained in:
Ron Buckton 2017-11-15 16:47:01 -08:00
parent a21a129abb
commit 86b0759b09
1 changed files with 5 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
src/compiler/checker.ts
View file

@ -10649,11 +10649,8 @@ namespace ts {
}
function getWidenedLiteralLikeTypeForContextualType(type: Type, contextualType: Type) {
if (!isLiteralContextualType(contextualType)) {
type = getWidenedLiteralType(type);
}
if (!isUniqueESSymbolContextualType(contextualType)) {
type = getWidenedUniqueESSymbolType(type);
if (!isLiteralLikeContextualType(contextualType)) {
type = getWidenedUniqueESSymbolType(getWidenedLiteralType(type));
}
return type;
}
@ -18838,27 +18835,23 @@ namespace ts {
isTypeAssertion(declaration.initializer) ? type : getWidenedLiteralType(type);
}
function isLiteralContextualType(contextualType: Type) {
function isLiteralLikeContextualType(contextualType: Type) {
if (contextualType) {
if (contextualType.flags & TypeFlags.TypeVariable) {
const constraint = getBaseConstraintOfType(contextualType) || emptyObjectType;
// If the type parameter is constrained to the base primitive type we're checking for,
// consider this a literal context. For example, given a type parameter 'T extends string',
// this causes us to infer string literal types for T.
if (constraint.flags & (TypeFlags.String | TypeFlags.Number | TypeFlags.Boolean | TypeFlags.Enum)) {
if (constraint.flags & (TypeFlags.String | TypeFlags.Number | TypeFlags.Boolean | TypeFlags.Enum | TypeFlags.UniqueESSymbol)) {
return true;
}
contextualType = constraint;
}
return maybeTypeOfKind(contextualType, (TypeFlags.Literal | TypeFlags.Index));
return maybeTypeOfKind(contextualType, (TypeFlags.Literal | TypeFlags.Index | TypeFlags.UniqueESSymbol));
}
return false;
}
function isUniqueESSymbolContextualType(contextualType: Type) {
return contextualType ? maybeTypeOfKind(contextualType, TypeFlags.UniqueESSymbol) : false;
}
function checkExpressionForMutableLocation(node: Expression, checkMode: CheckMode, contextualType?: Type): Type {
if (arguments.length === 2) {
contextualType = getContextualType(node);