Ensure check works when constraint is a union of arrayish types, just…

… like in `Promise.all`.
microsoft · Oct 5, 2021 · eebb1d4 · eebb1d4
1 parent d8844a7
commit eebb1d4
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -16516,7 +16516,7 @@ namespace ts {
                         if (t.flags & (TypeFlags.AnyOrUnknown | TypeFlags.InstantiableNonPrimitive | TypeFlags.Object | TypeFlags.Intersection) && t !== wildcardType && !isErrorType(t)) {
                             if (!type.declaration.nameType) {
                                 let constraint;
-                                if (isArrayType(t) || (t.flags & TypeFlags.Any) && (constraint = getConstraintOfTypeParameter(typeVariable)) && (isArrayType(constraint) || isTupleType(constraint))) {
+                                if (isArrayType(t) || (t.flags & TypeFlags.Any) && (constraint = getConstraintOfTypeParameter(typeVariable)) && everyType(constraint, or(isArrayType, isTupleType))) {
                                     return instantiateMappedArrayType(t, type, prependTypeMapping(typeVariable, t, mapper));
                                 }
                                 if (isGenericTupleType(t)) {