Function getTypeAtFlowLoopLabel

test/fixtures/snapshot/typescript.js:70650–70733

(flow)

                return createFlowType(getUnionOrEvolvingArrayType(antecedentTypes, subtypeReduction ? 2 /* UnionReduction.Subtype */ : 1 /* UnionReduction.Literal */), seenIncomplete);
            }
            function getTypeAtFlowLoopLabel(flow) {
                // If we have previously computed the control flow type for the reference at
                // this flow loop junction, return the cached type.
                var id = getFlowNodeId(flow);
                var cache = flowLoopCaches[id] || (flowLoopCaches[id] = new ts.Map());
                var key = getOrSetCacheKey();
                if (!key) {
                    // No cache key is generated when binding patterns are in unnarrowable situations
                    return declaredType;
                }
                var cached = cache.get(key);
                if (cached) {
                    return cached;
                }
                // If this flow loop junction and reference are already being processed, return
                // the union of the types computed for each branch so far, marked as incomplete.
                // It is possible to see an empty array in cases where loops are nested and the
                // back edge of the outer loop reaches an inner loop that is already being analyzed.
                // In such cases we restart the analysis of the inner loop, which will then see
                // a non-empty in-process array for the outer loop and eventually terminate because
                // the first antecedent of a loop junction is always the non-looping control flow
                // path that leads to the top.
                for (var i = flowLoopStart; i < flowLoopCount; i++) {
                    if (flowLoopNodes[i] === flow && flowLoopKeys[i] === key && flowLoopTypes[i].length) {
                        return createFlowType(getUnionOrEvolvingArrayType(flowLoopTypes[i], 1 /* UnionReduction.Literal */), /*incomplete*/ true);
                    }
                }
                // Add the flow loop junction and reference to the in-process stack and analyze
                // each antecedent code path.
                var antecedentTypes = [];
                var subtypeReduction = false;
                var firstAntecedentType;
                for (var _i = 0, _a = flow.antecedents; _i < _a.length; _i++) {
                    var antecedent = _a[_i];
                    var flowType = void 0;
                    if (!firstAntecedentType) {
                        // The first antecedent of a loop junction is always the non-looping control
                        // flow path that leads to the top.
                        flowType = firstAntecedentType = getTypeAtFlowNode(antecedent);
                    }
                    else {
                        // All but the first antecedent are the looping control flow paths that lead
                        // back to the loop junction. We track these on the flow loop stack.
                        flowLoopNodes[flowLoopCount] = flow;
                        flowLoopKeys[flowLoopCount] = key;
                        flowLoopTypes[flowLoopCount] = antecedentTypes;
                        flowLoopCount++;
                        var saveFlowTypeCache = flowTypeCache;
                        flowTypeCache = undefined;
                        flowType = getTypeAtFlowNode(antecedent);
                        flowTypeCache = saveFlowTypeCache;
                        flowLoopCount--;
                        // If we see a value appear in the cache it is a sign that control flow analysis
                        // was restarted and completed by checkExpressionCached. We can simply pick up
                        // the resulting type and bail out.
                        var cached_1 = cache.get(key);
                        if (cached_1) {
                            return cached_1;