Function getUnionOrEvolvingArrayType

test/fixtures/snapshot/typescript.js:70737–70746

(types, subtypeReduction)

            // is an evolving array type, we construct a combined evolving array type. Otherwise we
            // finalize all evolving array types.
            function getUnionOrEvolvingArrayType(types, subtypeReduction) {
                if (isEvolvingArrayTypeList(types)) {
                    return getEvolvingArrayType(getUnionType(ts.map(types, getElementTypeOfEvolvingArrayType)));
                }
                var result = getUnionType(ts.sameMap(types, finalizeEvolvingArrayType), subtypeReduction);
                if (result !== declaredType && result.flags & declaredType.flags & 1048576 /* TypeFlags.Union */ && ts.arraysEqual(result.types, declaredType.types)) {
                    return declaredType;
                }
                return result;
            }
            function getCandidateDiscriminantPropertyAccess(expr) {
                if (ts.isBindingPattern(reference) || ts.isFunctionExpressionOrArrowFunction(reference) || ts.isObjectLiteralMethod(reference)) {
                    // When the reference is a binding pattern or function or arrow expression, we are narrowing a pesudo-reference in