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Merge pull request #5639 from Microsoft/typecheckStatementsInCaseClause

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always check statements in case clause
This commit is contained in:
Vladimir Matveev
2015-11-12 13:11:57 -08:00
parent b3c4733a90 ebd1b873f1
commit 4dbae54af5
5 changed files with 106 additions and 6 deletions
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12
src/compiler/checker.ts
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@@ -12886,13 +12886,13 @@ namespace ts {
// In a 'switch' statement, each 'case' expression must be of a type that is assignable to or from the type of the 'switch' expression.
const caseType = checkExpression(caseClause.expression);
// Permit 'number[] | "foo"' to be asserted to 'string'.
if (expressionTypeIsStringLike && someConstituentTypeHasKind(caseType, TypeFlags.StringLike)) {
return;
}
const expressionTypeIsAssignableToCaseType =
// Permit 'number[] | "foo"' to be asserted to 'string'.
(expressionTypeIsStringLike && someConstituentTypeHasKind(caseType, TypeFlags.StringLike)) ||
isTypeAssignableTo(expressionType, caseType);
if (!isTypeAssignableTo(expressionType, caseType)) {
// check 'expressionType isAssignableTo caseType' failed, try the reversed check and report errors if it fails
if (!expressionTypeIsAssignableToCaseType) {
// 'expressionType is not assignable to caseType', try the reversed check and report errors if it fails
checkTypeAssignableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
}
}