Internal error when assining `_` to variable

[Leo]

constructor of LValue
interface constructor()

creates
	uint x := _

->

act: internal error: infer type of:WildExp
CallStack (from HasCallStack):
  error, called at Type.hs:363:10 in main:Type

[dxo]

This is the same as #74. _ is the wildcard syntax planned for #18 (calls to unknown code).