Resolver crasher on recursive types

[N1ark]

The type resolver crasher when parsing recursive types that reference each other (note no error is thrown if the recursive types are merged into one).

Stack trace:

RangeError: Maximum call stack size exceeded
    at Map.has (<anonymous>)
    at Qn.getMember (node_modules/assemblyscript/src/program.ts:2993:28)
    at Qn.getMember (node_modules/assemblyscript/src/program.ts:3252:25)
    at Qn.lookup (node_modules/assemblyscript/src/program.ts:3265:24)
    at mt.lookup (node_modules/assemblyscript/src/program.ts:2999:24)
    at qn.resolveTypeName (node_modules/assemblyscript/src/resolver.ts:589:30)
    at qn.resolveNamedType (node_modules/assemblyscript/src/resolver.ts:216:24)
    at qn.resolveType (node_modules/assemblyscript/src/resolver.ts:154:21)
    at qn.resolveNamedType (node_modules/assemblyscript/src/resolver.ts:321:23)
    at qn.resolveType (node_modules/assemblyscript/src/resolver.ts:154:21)

Code that crashes the resolver:

type RecMethod = () => RecReturn;
type RecReturn = RecMethod | null;

const test: RecMethod = () => null;

Equivalent code that doesn't crash the resolver (throws a AS100: Not implemented: Recursion in type aliases):

type RecMethod = () => RecMethod | null;
type RecReturn = returnof<RecMethod>;

const test: RecMethod = () => null;

Expected result: the resolver doesn't crash in both cases, and instead outputs the same (?) error (or at least handles the error in some way).