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Added specific checks for comparing stringlike types.

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This commit is contained in:
Daniel Rosenwasser 2015-11-06 12:58:03 -08:00
parent 5e2314303f
commit 8dbfe1ca63
1 changed files with 17 additions and 1 deletions
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18
src/compiler/checker.ts
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@ -9400,7 +9400,12 @@ namespace ts {
let targetType = getTypeFromTypeNode(node.type);
if (produceDiagnostics && targetType !== unknownType) {
let widenedType = getWidenedType(exprType);
if (!(isTypeAssignableTo(targetType, widenedType))) {
// Permit 'number[] | "foo"' to be asserted to 'string'.
const bothAreStringLike =
someConstituentTypeHasKind(targetType, TypeFlags.StringLike) &&
someConstituentTypeHasKind(widenedType, TypeFlags.StringLike);
if (!bothAreStringLike && !(isTypeAssignableTo(targetType, widenedType))) {
checkTypeAssignableTo(exprType, targetType, node, Diagnostics.Neither_type_0_nor_type_1_is_assignable_to_the_other);
}
}
@ -10244,6 +10249,10 @@ namespace ts {
case SyntaxKind.ExclamationEqualsToken:
case SyntaxKind.EqualsEqualsEqualsToken:
case SyntaxKind.ExclamationEqualsEqualsToken:
// Permit 'number[] | "foo"' to be asserted to 'string'.
if (someConstituentTypeHasKind(leftType, TypeFlags.StringLike) && someConstituentTypeHasKind(rightType, TypeFlags.StringLike)) {
return booleanType;
}
if (!isTypeAssignableTo(leftType, rightType) && !isTypeAssignableTo(rightType, leftType)) {
reportOperatorError();
}
@ -12703,6 +12712,7 @@ namespace ts {
let hasDuplicateDefaultClause = false;
let expressionType = checkExpression(node.expression);
const expressionTypeIsStringLike = someConstituentTypeHasKind(expressionType, TypeFlags.StringLike);
forEach(node.caseBlock.clauses, clause => {
// Grammar check for duplicate default clauses, skip if we already report duplicate default clause
if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@ -12723,6 +12733,12 @@ namespace ts {
// TypeScript 1.0 spec (April 2014):5.9
// In a 'switch' statement, each 'case' expression must be of a type that is assignable to or from the type of the 'switch' expression.
let caseType = checkExpression(caseClause.expression);
// Permit 'number[] | "foo"' to be asserted to 'string'.
if (expressionTypeIsStringLike && someConstituentTypeHasKind(caseType, TypeFlags.StringLike)) {
return;
}
if (!isTypeAssignableTo(expressionType, caseType)) {
// check 'expressionType isAssignableTo caseType' failed, try the reversed check and report errors if it fails
checkTypeAssignableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);