Maximum call stack size exceeded from getResolvedBaseConstraint

[aaronbeall]

TypeScript Version: 2.2.1 / nightly (2.2.0-dev.201xxxxx)

Code

I'm probably doing something stupid here but I can't quite wrap my mind around it and the compiler just crashes:

type ClassName<S> = keyof S;
type ClassNameMap<S> = { [K in keyof S]?: boolean }
type ClassNameObjectMap<S> = object & ClassNameMap<S>; // protects against passing non-objects, but breaks index lookups 
type ClassNameArg<S> = ClassName<S> | ClassNameObjectMap<S>;

export function css<S extends { [K in keyof S]: string }>(styles: S, ...classNames: ClassNameArg<S>[]): string {
  const args = classNames.map(arg => {
    if (arg == null) {
      return null;
    }
    if (typeof arg == "string") {
      return styles[arg];
    }
    if (typeof arg == "object") {
      return Object.keys(arg).reduce<ClassNameObject>((obj: ClassNameObject, key: keyof S) => {
        const exportedClassName = styles[key];
        obj[exportedClassName] = (arg as ClassNameMap<S>)[key]; 
        return obj;
      }, {});
    }
  });

  // return classnamer(...args);
  return "";
}

If I comment out the whole function body the errors go away.

Expected behavior:

No error, type S constrained to objects with only string properties and index lookups don't break.

Actual behavior:

Compiler fails with:

Process: Error processing message: Maximum call stack size exceeded RangeError: Maximum call stack size exceeded
    at isSimpleTypeRelatedTo (evalmachine.<anonymous>:28208:39)
    at isRelatedTo (evalmachine.<anonymous>:28354:21)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)
    at isRelatedTo (evalmachine.<anonymous>:28413:38)

[ahejlsberg]

This looks to be the same issue as #14896.