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Correct type for rest element in destructuring declaration

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This commit is contained in:
Anders Hejlsberg 2014-12-12 07:38:08 -08:00
parent a42df7547e
commit e26c3a68fc
1 changed files with 19 additions and 12 deletions
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31
src/compiler/checker.ts
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@ -1717,19 +1717,26 @@ module ts {
error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(parentType), declarationNameToString(name));
return unknownType;
}
return type;
}
// For an array binding element the specified or inferred type of the parent must be assignable to any[]
if (!isTypeAssignableTo(parentType, anyArrayType)) {
error(pattern, Diagnostics.Type_0_is_not_an_array_type, typeToString(parentType));
return unknownType;
}
// Use specific property type when parent is a tuple or numeric index type when parent is an array
var propName = "" + indexOf(pattern.elements, declaration);
var type = isTupleLikeType(parentType) ? getTypeOfPropertyOfType(parentType, propName) : getIndexTypeOfType(parentType, IndexKind.Number);
if (!type) {
error(declaration, Diagnostics.Type_0_has_no_property_1, typeToString(parentType), propName);
return unknownType;
else {
// For an array binding element the specified or inferred type of the parent must be assignable to any[]
if (!isTypeAssignableTo(parentType, anyArrayType)) {
error(pattern, Diagnostics.Type_0_is_not_an_array_type, typeToString(parentType));
return unknownType;
}
if (!declaration.dotDotDotToken) {
// Use specific property type when parent is a tuple or numeric index type when parent is an array
var propName = "" + indexOf(pattern.elements, declaration);
var type = isTupleLikeType(parentType) ? getTypeOfPropertyOfType(parentType, propName) : getIndexTypeOfType(parentType, IndexKind.Number);
if (!type) {
error(declaration, Diagnostics.Type_0_has_no_property_1, typeToString(parentType), propName);
return unknownType;
}
}
else {
// Rest element has an array type with the same element type as the parent type
var type = createArrayType(getIndexTypeOfType(parentType, IndexKind.Number));
}
}
return type;
}