proc arguments are in scope when the result type definition is being processed

This is intended for type deduction depending on the arguments
proc foo(x: type): type(expr(x))

tests/compile/ttypeselectors.nim

@@ -35,3 +35,6 @@ var y*: type(t2(100)) = "test"
 proc t6*(x: type(t3(0))): type(t1(0)) =
   result = $x
 
+proc t7*(x: int): type($x) =
+  result = "test"
+