error: type annotation mismatch
  --> line 1:1
   |
 1 | let reading: Measured<Normal(10.0, 2.0)> = sensor_read();
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ inferred type does not match annotation
   |
   = note: `reading` is annotated as Normal(10, 2) (mean 10, stddev 2), but the inferred distribution has mean 10, stddev 1

