Transmute value to arbitrary type with mutually recursive functions

[1derless]

Quick Summary: Mutually recursive functions can be used to transmute a value to an arbitrary type.

SSCCE

-- repl says f has type `a -> b -> c`
f x y = g x y
g x y = if False then f x y else y

eraseType : a -> b
eraseType x = f () x

• Elm: 0.19.1
• Browser: n/a
• Operating System: Arch Linux

Additional Details

Ellie: https://ellie-app.com/jr8JcxccdXba1

I think the types of f and g should be a -> b -> b, and my Haskell compiler (ghc) agrees.

In addition, attempting to print the type of g in the repl causes the crash in the mutual recursion-related issue #2207.

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