[New module system] (^^) crashes on unqualified exponent in inter-module function instantiation

[WeeknightMVP]

In functors-merge, Cryptol crashes when trying to coerce an unqualified exponent for (^^) in a functor instantiation across modules. (Whether parameters are used is not relevant to the crash.)

// F.cry
module F where

parameter
  type n: #

submodule S where
  parameter
    type m: #

  x : Integer
  x = 0 ^^ 1  // crashes
  // x = 0 ^^ (1 : Integer)  // works

// T.cry
module T where

import F where
  type n = 1

import submodule S where
  type m = 1

$ ./cry run
┏━╸┏━┓╻ ╻┏━┓╺┳╸┏━┓╻
┃  ┣┳┛┗┳┛┣━┛ ┃ ┃ ┃┃
┗━╸╹┗╸ ╹ ╹   ╹ ┗━┛┗━╸
version 2.13.0.99 (9b63a18, modified)
Cryptol> :m T
Loading module Cryptol
Loading interface module `parameter` interface of F
Loading module F
Loading module T
T> x
cryptol: You have encountered a bug in Cryptol's implementation.
*** Please create an issue at https://github.com/GaloisInc/cryptol/issues

%< ---------------------------------------------------
  Revision:  9b63a18044e0861a05a3c91213b6d383b2289911
  Branch:    functors-merge (uncommited files present)
  Location:  [Eval] expV
  Message:   TCon (TC TCBit) [] not int class `Integral`
CallStack (from HasCallStack):
  panic, called at src/Cryptol/Utils/Panic.hs:21:9 in cryptol-2.13.0.99-inplace:Cryptol.Utils.Panic
  panic, called at src/Cryptol/Backend/Monad.hs:410:17 in cryptol-2.13.0.99-inplace:Cryptol.Backend.Monad
  evalPanic, called at src/Cryptol/Eval/Generic.hs:528:16 in cryptol-2.13.0.99-inplace:Cryptol.Eval.Generic
%< ---------------------------------------------------

Explicitly qualifying the exponent as an Integer works as expected, as does evaluating the expression outside a nested submodule...

// G.cry
module G where
  parameter
    type n: #

  x : Integer
  x = 0 ^^ 1  // works

// U.cry
module U where

import G where
  type n = 1

$ ./cry run
...
Cryptol> 0 ^^ 1 : Integer
0
Cryptol> :m U
Loading module Cryptol
Loading interface module `parameter` interface of G
Loading module G
Loading module U
U> x
0

... or doing all of the above in a single module.

// X.cry
module X where

submodule S where
  parameter
    type n: #

  submodule S' where
    parameter
      type m: #

    x : Integer
    x = 0 ^^ 1  // works

import submodule S where
  type n = 1

import submodule S' where
  type m = 1

$ ./cry run
...
Cryptol> :m X
Loading module Cryptol
Loading module X
X> x
0