Function getTypeAtFlowBranchLabel

test/fixtures/snapshot/typescript.js:70597–70649

(flow)

                return createFlowType(type, isIncomplete(flowType));
            }
            function getTypeAtFlowBranchLabel(flow) {
                var antecedentTypes = [];
                var subtypeReduction = false;
                var seenIncomplete = false;
                var bypassFlow;
                for (var _i = 0, _a = flow.antecedents; _i < _a.length; _i++) {
                    var antecedent = _a[_i];
                    if (!bypassFlow && antecedent.flags & 128 /* FlowFlags.SwitchClause */ && antecedent.clauseStart === antecedent.clauseEnd) {
                        // The antecedent is the bypass branch of a potentially exhaustive switch statement.
                        bypassFlow = antecedent;
                        continue;
                    }
                    var flowType = getTypeAtFlowNode(antecedent);
                    var type = getTypeFromFlowType(flowType);
                    // If the type at a particular antecedent path is the declared type and the
                    // reference is known to always be assigned (i.e. when declared and initial types
                    // are the same), there is no reason to process more antecedents since the only
                    // possible outcome is subtypes that will be removed in the final union type anyway.
                    if (type === declaredType && declaredType === initialType) {
                        return type;
                    }
                    ts.pushIfUnique(antecedentTypes, type);
                    // If an antecedent type is not a subset of the declared type, we need to perform
                    // subtype reduction. This happens when a "foreign" type is injected into the control
                    // flow using the instanceof operator or a user defined type predicate.
                    if (!isTypeSubsetOf(type, declaredType)) {
                        subtypeReduction = true;
                    }
                    if (isIncomplete(flowType)) {
                        seenIncomplete = true;
                    }
                }
                if (bypassFlow) {
                    var flowType = getTypeAtFlowNode(bypassFlow);
                    var type = getTypeFromFlowType(flowType);
                    // If the bypass flow contributes a type we haven't seen yet and the switch statement
                    // isn't exhaustive, process the bypass flow type. Since exhaustiveness checks increase
                    // the risk of circularities, we only want to perform them when they make a difference.
                    if (!ts.contains(antecedentTypes, type) && !isExhaustiveSwitchStatement(bypassFlow.switchStatement)) {
                        if (type === declaredType && declaredType === initialType) {
                            return type;
                        }
                        antecedentTypes.push(type);
                        if (!isTypeSubsetOf(type, declaredType)) {
                            subtypeReduction = true;
                        }
                        if (isIncomplete(flowType)) {
                            seenIncomplete = true;
                        }
                    }
                }
                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.