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Use getIndexedAccess to compute type for contextual rest parameters

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This commit is contained in:
Anders Hejlsberg 2019-02-10 07:48:22 -08:00
parent bbf559b9c7
commit 9a0a838d12
1 changed files with 10 additions and 11 deletions
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21
src/compiler/checker.ts
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@ -21550,13 +21550,8 @@ namespace ts {
}
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[paramCount]);
if (isTupleType(restType)) {
if (pos - paramCount < getLengthOfTupleType(restType)) {
return restType.typeArguments![pos - paramCount];
}
return getRestTypeOfTupleType(restType);
}
return getIndexTypeOfType(restType, IndexKind.Number);
const indexType = getLiteralType(pos - paramCount);
return getIndexedAccessType(restType, indexType);
}
return undefined;
}
@ -21564,18 +21559,22 @@ namespace ts {
function getRestTypeAtPosition(source: Signature, pos: number): Type {
const paramCount = getParameterCount(source);
const restType = getEffectiveRestType(source);
if (restType && pos === paramCount - 1) {
const nonRestCount = paramCount - (restType ? 1 : 0);
if (restType && pos === nonRestCount) {
return restType;
}
const start = restType ? Math.min(pos, paramCount - 1) : pos;
const types = [];
const names = [];
for (let i = start; i < paramCount; i++) {
for (let i = pos; i < nonRestCount; i++) {
types.push(getTypeAtPosition(source, i));
names.push(getParameterNameAtPosition(source, i));
}
if (restType) {
types.push(getIndexedAccessType(restType, numberType));
names.push(getParameterNameAtPosition(source, nonRestCount));
}
const minArgumentCount = getMinArgumentCount(source);
const minLength = minArgumentCount < start ? 0 : minArgumentCount - start;
const minLength = minArgumentCount < pos ? 0 : minArgumentCount - pos;
return createTupleType(types, minLength, !!restType, /*readonly*/ false, names);
}