overload-fences.ts:12:13 - error SC1090: calls selecting an overload signature of a generic function (only the implementation signature monomorphizes) is not supported yet

  11 | }
  12 | console.log(twice("q").length);
     |             ^~~~~~~~~~
  13 | 

overload-fences.ts:22:7 - error SC2001: values of type '{ (x: "a"): string; (x: "b"): number; }' cannot be compiled yet (supported: number, string, boolean, arrays, Maps, Sets, RegExp, functions, classes, records, unions of those, and 'unknown')

  21 | // directly compiles (corpus 1851).
  22 | const asValue = pick;
     |       ^~~~~~~
  23 | console.log(typeof asValue);

overload-fences.ts:23:20 - error SC2004: uses of 'asValue' inherit the blocker on its declaration

  22 | const asValue = pick;
  23 | console.log(typeof asValue);
     |                    ^~~~~~~
  24 | 

  hint: the declaration of 'asValue' did not compile — fix the diagnostic reported there and these sites clear with it