synonym type not allowed

[Erik Zuurbier]

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> Type synonyms can not be allowed as instances of type classes.
> At least, not as they are now. The problem is that the compiler
> can not determine whether the expression (3, 4.0) is of type (Int, Real)
> or of your MyType.

You may regard instances of type synonyms as an instance of the basic
type, then you don't have the problem that the compiler cannot determine
whether the expression (3, 4.0) is of type (Int, Real) or of your
MyType. You always use the instances of type (Int, Real).

That is simple. That brings down the word synonym to what the word actually means:
a different word for exactly the same thing. I cannot immagine that language developers
have never thought of this. A synonym type would be reduced to a syntactic issue. What
do we lose that way?

Erik Zuurbier
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