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Validate const assertion operand

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This commit is contained in:
Anders Hejlsberg 2019-01-19 10:25:41 -08:00
parent beb02703b8
commit ec30c20ec9
2 changed files with 30 additions and 1 deletions
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27
src/compiler/checker.ts
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@ -9104,7 +9104,7 @@ namespace ts {
function createTupleType(elementTypes: ReadonlyArray<Type>, minLength = elementTypes.length, hasRestElement = false, readonly = false, associatedNames?: __String[]) {
const arity = elementTypes.length;
if (arity === 1 && hasRestElement) {
return createArrayType(elementTypes[0]);
return createArrayType(elementTypes[0], readonly);
}
const tupleType = getTupleTypeOfArity(arity, minLength, arity > 0 && hasRestElement, readonly, associatedNames);
return elementTypes.length ? createTypeReference(tupleType, elementTypes) : tupleType;
@ -21158,9 +21158,34 @@ namespace ts {
return checkAssertionWorker(node, node.type, node.expression);
}
function isValidConstAssertionArgument(node: Node): boolean {
switch (node.kind) {
case SyntaxKind.StringLiteral:
case SyntaxKind.NoSubstitutionTemplateLiteral:
case SyntaxKind.NumericLiteral:
case SyntaxKind.BigIntLiteral:
case SyntaxKind.TrueKeyword:
case SyntaxKind.FalseKeyword:
case SyntaxKind.ArrayLiteralExpression:
case SyntaxKind.ObjectLiteralExpression:
return true;
case SyntaxKind.ParenthesizedExpression:
return isValidConstAssertionArgument((<ParenthesizedExpression>node).expression);
case SyntaxKind.PrefixUnaryExpression:
const op = (<PrefixUnaryExpression>node).operator;
const arg = (<PrefixUnaryExpression>node).operand;
return op === SyntaxKind.MinusToken && (arg.kind === SyntaxKind.NumericLiteral || arg.kind === SyntaxKind.BigIntLiteral) ||
op === SyntaxKind.PlusToken && arg.kind === SyntaxKind.NumericLiteral;
}
return false;
}
function checkAssertionWorker(errNode: Node, type: TypeNode, expression: UnaryExpression | Expression, checkMode?: CheckMode) {
let exprType = checkExpression(expression, checkMode);
if (isConstTypeReference(type)) {
if (!isValidConstAssertionArgument(expression)) {
error(expression, Diagnostics.A_const_assertion_can_only_be_applied_to_a_string_number_boolean_array_or_object_literal);
}
return getRegularTypeOfLiteralType(exprType);
}
checkSourceElement(type);

4
src/compiler/diagnosticMessages.json
View file

@ -1027,6 +1027,10 @@
"category": "Error",
"code": 1354
},
"A 'const' assertion can only be applied to a string, number, boolean, array, or object literal.": {
"category": "Error",
"code": 1355
},
"Duplicate identifier '{0}'.": {
"category": "Error",