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Fix template literal type relations (#43440)

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* Fix template literal relationships

* Accept new baselines

* Add regression test
This commit is contained in:
Anders Hejlsberg
2021-03-30 15:53:15 -07:00
committed by GitHub
parent 819651eb5f
commit 3dd68b878a
6 changed files with 69 additions and 27 deletions
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19
src/compiler/checker.ts
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@@ -18274,6 +18274,11 @@ namespace ts {
}
}
else if (target.flags & TypeFlags.TemplateLiteral) {
if (source.flags & TypeFlags.TemplateLiteral) {
// Report unreliable variance for type variables referenced in template literal type placeholders.
// For example, `foo-${number}` is related to `foo-${string}` even though number isn't related to string.
instantiateType(source, makeFunctionTypeMapper(reportUnreliableMarkers));
}
const result = inferTypesFromTemplateLiteralType(source, target as TemplateLiteralType);
if (result && every(result, (r, i) => isValidTypeForTemplateLiteralPlaceholder(r, (target as TemplateLiteralType).types[i]))) {
return Ternary.True;
@@ -18318,20 +18323,6 @@ namespace ts {
return result;
}
}
else if (source.flags & TypeFlags.TemplateLiteral) {
if (target.flags & TypeFlags.TemplateLiteral &&
(source as TemplateLiteralType).texts.length === (target as TemplateLiteralType).texts.length &&
(source as TemplateLiteralType).types.length === (target as TemplateLiteralType).types.length &&
every((source as TemplateLiteralType).texts, (t, i) => t === (target as TemplateLiteralType).texts[i]) &&
every((instantiateType(source, makeFunctionTypeMapper(reportUnreliableMarkers)) as TemplateLiteralType).types, (t, i) => !!((target as TemplateLiteralType).types[i].flags & (TypeFlags.Any | TypeFlags.String)) || !!isRelatedTo(t, (target as TemplateLiteralType).types[i], /*reportErrors*/ false))) {
return Ternary.True;
}
const constraint = getBaseConstraintOfType(source);
if (constraint && constraint !== source && (result = isRelatedTo(constraint, target, reportErrors))) {
resetErrorInfo(saveErrorInfo);
return result;
}
}
else if (source.flags & TypeFlags.StringMapping) {
if (target.flags & TypeFlags.StringMapping && (<StringMappingType>source).symbol === (<StringMappingType>target).symbol) {
if (result = isRelatedTo((<StringMappingType>source).type, (<StringMappingType>target).type, reportErrors)) {