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Propegate variance a bit more selectively

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This commit is contained in:
Wesley Wigham
2019-05-31 10:34:19 -07:00
parent 20c928eb77
commit f21903b7f4
1 changed files with 12 additions and 9 deletions
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src/compiler/checker.ts
+12 -9
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@@ -12981,13 +12981,16 @@ namespace ts {
return result;
}
function propegateSidebandVarianceFlags(variances: VarianceFlags[]) {
function propegateSidebandVarianceFlags(typeArguments: readonly Type[], variances: VarianceFlags[]) {
if (outofbandVarianceMarkerHandler) {
if (some(variances, v => !!(v & VarianceFlags.Unmeasurable))) {
outofbandVarianceMarkerHandler(/*onlyUnreliable*/ false);
}
if (some(variances, v => !!(v & VarianceFlags.Unreliable))) {
outofbandVarianceMarkerHandler(/*onlyUnreliable*/ true);
for (let i = 0; i < variances.length; i++) {
const v = variances[i];
if (v & VarianceFlags.Unmeasurable) {
instantiateType(typeArguments[i], reportUnmeasurableMarkers);
}
if (v & VarianceFlags.Unreliable) {
instantiateType(typeArguments[i], reportUnreliableMarkers);
}
}
}
}
@@ -13013,10 +13016,10 @@ namespace ts {
// We're in the middle of variance checking - integrate any unmeasurable/unreliable flags from this cached component
if (source.flags & (TypeFlags.Object | TypeFlags.Conditional) && source.aliasSymbol &&
source.aliasTypeArguments && source.aliasSymbol === target.aliasSymbol) {
propegateSidebandVarianceFlags(getAliasVariances(source.aliasSymbol));
propegateSidebandVarianceFlags(source.aliasTypeArguments, getAliasVariances(source.aliasSymbol));
}
if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target) {
propegateSidebandVarianceFlags(getVariances((<TypeReference>source).target));
if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target && length((<TypeReference>source).typeArguments)) {
propegateSidebandVarianceFlags((<TypeReference>source).typeArguments!, getVariances((<TypeReference>source).target));
}
}
return related === RelationComparisonResult.Succeeded ? Ternary.True : Ternary.False;