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Revise complex rest parameter handling in relations and inference

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This commit is contained in:
Anders Hejlsberg 2018-08-25 07:29:15 -07:00
parent 4e44b08020
commit f5f61335ee
1 changed files with 9 additions and 9 deletions
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18
src/compiler/checker.ts
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@ -10723,8 +10723,9 @@ namespace ts {
const sourceCount = getParameterCount(source);
const sourceRestType = getNonArrayRestType(source);
const targetRestType = sourceRestType ? getNonArrayRestType(target) : undefined;
if (sourceRestType && !(targetRestType && sourceCount === targetCount)) {
const targetRestType = getNonArrayRestType(target);
if (sourceRestType && targetRestType && sourceCount !== targetCount) {
// We're not able to relate misaliged complex rest parameters
return Ternary.False;
}
@ -10750,11 +10751,12 @@ namespace ts {
}
}
const paramCount = Math.max(sourceCount, targetCount);
const lastIndex = paramCount - 1;
const paramCount = sourceRestType || targetRestType ? Math.min(sourceCount, targetCount) : Math.max(sourceCount, targetCount);
const restIndex = sourceRestType || targetRestType ? paramCount - 1 : -1;
for (let i = 0; i < paramCount; i++) {
const sourceType = i === lastIndex && sourceRestType || getTypeAtPosition(source, i);
const targetType = i === lastIndex && targetRestType || getTypeAtPosition(target, i);
const sourceType = i === restIndex ? getRestTypeAtPosition(source, i) : getTypeAtPosition(source, i);
const targetType = i === restIndex ? getRestTypeAtPosition(target, i) : getTypeAtPosition(target, i);
// In order to ensure that any generic type Foo<T> is at least co-variant with respect to T no matter
// how Foo uses T, we need to relate parameters bi-variantly (given that parameters are input positions,
// they naturally relate only contra-variantly). However, if the source and target parameters both have
@ -13049,11 +13051,9 @@ namespace ts {
const targetCount = getParameterCount(target);
const sourceRestType = getEffectiveRestType(source);
const targetRestType = getEffectiveRestType(target);
const maxCount = sourceRestType && targetRestType ? Math.max(sourceCount, targetCount) :
const paramCount = targetRestType ? Math.min(targetCount - 1, sourceCount) :
sourceRestType ? targetCount :
targetRestType ? sourceCount :
Math.min(sourceCount, targetCount);
const paramCount = targetRestType ? Math.min(targetCount - 1, maxCount) : maxCount;
for (let i = 0; i < paramCount; i++) {
callback(getTypeAtPosition(source, i), getTypeAtPosition(target, i));
}