previously, `#eval` would happily evaluate expressions that contain
`sorry`, either explicitly or because of failing tactics. In conjunction
with operations like array access this can lead to the lean process
crashing, which isn't particularly great.
So how `#eval` will refuse to run code that (transitively) depends on
the `sorry` axiom (using the same code as `#print axioms`).
If the user really wants to run it, they can use `#eval!`.
Closes#1697
@Kha we do that in Lean 3. It helps when the error is due to incorrect universe levels.
BTW, I had to update `tests/lean/server/content_diag.json` since the
error message is different, but a few other stuff changed too.
Could you please take a look whether the test is still correct?
