Function createOptionalCallSignature

test/fixtures/snapshot/typescript.js:58000–58005

(signature, callChainFlags)

                || (signature.optionalCallSignatureCache[key] = createOptionalCallSignature(signature, callChainFlags));
        }
        function createOptionalCallSignature(signature, callChainFlags) {
            ts.Debug.assert(callChainFlags === 8 /* SignatureFlags.IsInnerCallChain */ || callChainFlags === 16 /* SignatureFlags.IsOuterCallChain */, "An optional call signature can either be for an inner call chain or an outer call chain, but not both.");
            var result = cloneSignature(signature);
            result.flags |= callChainFlags;
            return result;
        }
        function getExpandedParameters(sig, skipUnionExpanding) {
            if (signatureHasRestParameter(sig)) {
                var restIndex_1 = sig.parameters.length - 1;