[m-rev.] for review: structured types in error messages

[Zoltan Somogyi]

2022-02-20 02:08 GMT+11:00 "Zoltan Somogyi" <zoltan.somogyi at runbox.com>:
> For review by anyone.

In the absence of a review or a promise of a review by then,
I intend to commit this diff this afternoon.

Zoltan.