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Get literal type only once

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Nathan Shively-Sanders
2016-11-01 09:09:40 -07:00
parent ebef408dfa
commit d7f5fc8fcf
1 changed files with 6 additions and 5 deletions
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11
src/compiler/checker.ts
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@@ -16882,7 +16882,8 @@ namespace ts {
let firstDefaultClause: CaseOrDefaultClause;
let hasDuplicateDefaultClause = false;
let expressionType = checkExpression(node.expression);
const expressionType = checkExpression(node.expression);
const expressionIsLiteral = isLiteralType(expressionType);
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) {
@@ -16905,14 +16906,14 @@ namespace ts {
// to or from the type of the 'switch' expression.
let caseType = checkExpression(caseClause.expression);
const caseIsLiteral = isLiteralType(caseType);
const expressionIsLiteral = isLiteralType(expressionType);
let literalExpressionType = expressionType;
if (!caseIsLiteral || !expressionIsLiteral) {
caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
expressionType = expressionIsLiteral ? getBaseTypeOfLiteralType(expressionType) : expressionType;
literalExpressionType = getBaseTypeOfLiteralType(expressionType);
}
if (!isTypeEqualityComparableTo(expressionType, caseType)) {
if (!isTypeEqualityComparableTo(literalExpressionType, caseType)) {
// expressionType is not comparable to caseType, try the reversed check and report errors if it fails
checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
checkTypeComparableTo(caseType, literalExpressionType, caseClause.expression, /*headMessage*/ undefined);
}
}
forEach(clause.statements, checkSourceElement);