can not match against builtin type() constructor

[jurgenvinju]

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Describe the bug

data X = x();

if (type(Symbol s, map[Symbol, Production] g) := #X) {
  println("<s> is defined in <g>");
}

This does not match or print anything, but it should simply match the type constructor that is produced by #X against the pattern and bind the symbol and the grammar.

Apparently there is a test missing for this as well.