[racket] Typed Racket: (Parameterof (HashTable ...))

From: Asumu Takikawa (asumu at ccs.neu.edu)
Date: Fri Feb 14 21:47:03 EST 2014

On 2014-02-14 21:29:00 -0500, Asumu Takikawa wrote:
> I'm guessing the problem is that the expected type from the annotation
> of ph is not propagated correctly while the type inference system tries
> to infer the concrete type for `make-parameter`. It looks like
> something we could fix, but it might not be an obvious fix.

Actually, this is probably an instance of a limitation of TR for
polymorphic functions. TR doesn't currently handle type inference for
function arguments that are themselves polymorphic, which I think
includes your case. So a near-term fix may be unlikely.

The guide entry on the limitation:
  http://docs.racket-lang.org/ts-guide/caveats.html#%28part._.Type_inference_for_polymorphic_functions%29

Cheers,
Asumu

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