Function getResolvedBaseConstraint

test/fixtures/snapshot/typescript.js:58953–59060

* Return the resolved base constraint of a type variable. The noConstraintType singleton is returned if the * type variable has no constraint, and the circularConstraintType singleton is returned if the constraint * circularly references the type variable.

(type)

         * circularly references the type variable.
         */
        function getResolvedBaseConstraint(type) {
            if (type.resolvedBaseConstraint) {
                return type.resolvedBaseConstraint;
            }
            var stack = [];
            return type.resolvedBaseConstraint = getTypeWithThisArgument(getImmediateBaseConstraint(type), type);
            function getImmediateBaseConstraint(t) {
                if (!t.immediateBaseConstraint) {
                    if (!pushTypeResolution(t, 4 /* TypeSystemPropertyName.ImmediateBaseConstraint */)) {
                        return circularConstraintType;
                    }
                    var result = void 0;
                    // We always explore at least 10 levels of nested constraints. Thereafter, we continue to explore
                    // up to 50 levels of nested constraints provided there are no "deeply nested" types on the stack
                    // (i.e. no types for which five instantiations have been recorded on the stack). If we reach 50
                    // levels of nesting, we are presumably exploring a repeating pattern with a long cycle that hasn't
                    // yet triggered the deeply nested limiter. We have no test cases that actually get to 50 levels of
                    // nesting, so it is effectively just a safety stop.
                    var identity_1 = getRecursionIdentity(t);
                    if (stack.length < 10 || stack.length < 50 && !ts.contains(stack, identity_1)) {
                        stack.push(identity_1);
                        result = computeBaseConstraint(getSimplifiedType(t, /*writing*/ false));
                        stack.pop();
                    }
                    if (!popTypeResolution()) {
                        if (t.flags & 262144 /* TypeFlags.TypeParameter */) {
                            var errorNode = getConstraintDeclaration(t);
                            if (errorNode) {
                                var diagnostic = error(errorNode, ts.Diagnostics.Type_parameter_0_has_a_circular_constraint, typeToString(t));
                                if (currentNode && !ts.isNodeDescendantOf(errorNode, currentNode) && !ts.isNodeDescendantOf(currentNode, errorNode)) {
                                    ts.addRelatedInfo(diagnostic, ts.createDiagnosticForNode(currentNode, ts.Diagnostics.Circularity_originates_in_type_at_this_location));
                                }
                            }
                        }
                        result = circularConstraintType;
                    }
                    t.immediateBaseConstraint = result || noConstraintType;
                }
                return t.immediateBaseConstraint;
            }
            function getBaseConstraint(t) {
                var c = getImmediateBaseConstraint(t);
                return c !== noConstraintType && c !== circularConstraintType ? c : undefined;
            }
            function computeBaseConstraint(t) {
                if (t.flags & 262144 /* TypeFlags.TypeParameter */) {
                    var constraint = getConstraintFromTypeParameter(t);
                    return t.isThisType || !constraint ?
                        constraint :
                        getBaseConstraint(constraint);
                }
                if (t.flags & 3145728 /* TypeFlags.UnionOrIntersection */) {
                    var types = t.types;
                    var baseTypes = [];
                    var different = false;
                    for (var _i = 0, types_7 = types; _i < types_7.length; _i++) {
                        var type_4 = types_7[_i];
                        var baseType = getBaseConstraint(type_4);