Function createUnionSignature

test/fixtures/snapshot/typescript.js:57981–57988

(signature, unionSignatures)

            return result;
        }
        function createUnionSignature(signature, unionSignatures) {
            var result = cloneSignature(signature);
            result.compositeSignatures = unionSignatures;
            result.compositeKind = 1048576 /* TypeFlags.Union */;
            result.target = undefined;
            result.mapper = undefined;
            return result;
        }
        function getOptionalCallSignature(signature, callChainFlags) {
            if ((signature.flags & 24 /* SignatureFlags.CallChainFlags */) === callChainFlags) {
                return signature;