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Correct support for type guards with unions containing enums

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This commit is contained in:
Anders Hejlsberg
2015-01-24 17:21:49 -08:00
parent 29776f4e9b
commit 95a314a754
1 changed files with 40 additions and 13 deletions
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src/compiler/checker.ts
+40 -13
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@@ -107,6 +107,21 @@ module ts {
var diagnostics: Diagnostic[] = [];
var diagnosticsModified: boolean = false;
var primitiveTypeInfo: Map<{ type: Type; flags: TypeFlags }> = {
"string": {
type: stringType,
flags: TypeFlags.StringLike
},
"number": {
type: numberType,
flags: TypeFlags.NumberLike
},
"boolean": {
type: booleanType,
flags: TypeFlags.Boolean
}
};
function addDiagnostic(diagnostic: Diagnostic) {
diagnostics.push(diagnostic);
diagnosticsModified = true;
@@ -4454,12 +4469,15 @@ module ts {
Debug.fail("should not get here");
}
// Remove one or more primitive types from a union type
function subtractPrimitiveTypes(type: Type, subtractMask: TypeFlags): Type {
// For a union type, remove all constituent types for which the given flags have the given state
function removeTypesFromUnionType(type: Type, maskFlags: TypeFlags, maskState: boolean): Type {
if (type.flags & TypeFlags.Union) {
var types = (<UnionType>type).types;
if (forEach(types, t => t.flags & subtractMask)) {
return getUnionType(filter(types, t => !(t.flags & subtractMask)));
if (forEach(types, t => !(t.flags & maskFlags) !== maskState)) {
var reducedType = getUnionType(filter(types, t => !(t.flags & maskFlags) === maskState));
if (reducedType !== emptyObjectType) {
return reducedType;
}
}
}
return type;
@@ -4635,8 +4653,8 @@ module ts {
// Stop at the first containing function or module declaration
break loop;
}
// Use narrowed type if it is a subtype and construct contains no assignments to variable
if (narrowedType !== type && isTypeSubtypeOf(narrowedType, type)) {
// Use narrowed type if construct contains no assignments to variable
if (narrowedType !== type) {
if (isVariableAssignedWithin(symbol, node)) {
break;
}
@@ -4656,20 +4674,29 @@ module ts {
if (left.expression.kind !== SyntaxKind.Identifier || getResolvedSymbol(<Identifier>left.expression) !== symbol) {
return type;
}
var t = right.text;
var checkType: Type = t === "string" ? stringType : t === "number" ? numberType : t === "boolean" ? booleanType : emptyObjectType;
var typeInfo = primitiveTypeInfo[right.text];
if (expr.operator === SyntaxKind.ExclamationEqualsEqualsToken) {
assumeTrue = !assumeTrue;
}
if (assumeTrue) {
// The assumed result is true. If check was for a primitive type, that type is the narrowed type. Otherwise we can
// remove the primitive types from the narrowed type.
return checkType === emptyObjectType ? subtractPrimitiveTypes(type, TypeFlags.String | TypeFlags.Number | TypeFlags.Boolean) : checkType;
// Assumed result is true. If check was not for a primitive type, remove all primitive types
if (!typeInfo) {
return removeTypesFromUnionType(type, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.Boolean, true);
}
// Check was for a primitive type, return that primitive type if it is a subtype
if (isTypeSubtypeOf(typeInfo.type, type)) {
return typeInfo.type;
}
// Otherwise, remove all types that aren't of the primitive type kind
return removeTypesFromUnionType(type, typeInfo.flags, false);
}
else {
// The assumed result is false. If check was for a primitive type we can remove that type from the narrowed type.
// Assumed result is false. If check was for a primitive type, remove that primitive type
if (typeInfo) {
return removeTypesFromUnionType(type, typeInfo.flags, true);
}
// Otherwise we don't have enough information to do anything.
return checkType === emptyObjectType ? type : subtractPrimitiveTypes(type, checkType.flags);
return type;
}
}