The trace class Meta.synthInstance.answer isn't registered, so it can't
be used.
I set `inherited := true`, because I think it is a useful trace to have.
In particular it tells you when an instance has been found that has a
too large size. This is very useful information.
Remark: this commit removes the `jason1.lean` test. Motivation: It
breaks all the time due to changes we make, and it is not clear anymore
what it is testing.
---------
Co-authored-by: Joachim Breitner <mail@joachim-breitner.de>
The previous implementation was using the following heuristic
```lean
-- heuristic: use non-dependent arrows only if possible for whole group to avoid
-- noisy mix like `(α : Type) → Type → (γ : Type) → ...`.
let dependent := curNames.any fun n => hasIdent n.getId stxBody
```
The result produced by this heuristic was **not** producing an
accidental name capture, but I agree
it was confusing to have `∀ (a : True), ∃ a, a = a : Prop` instead of
`True → ∃ a, a = a : Prop` since there is no dependency.
AFAICT, all examples affected by this commit have a better output now.
cc @digma0 @kha
