previously, only the WellFounded code was making use of the error
location in the RecApp-metadata. We can do the same for structural
recursion. This way,
```
def f (n : Nat) : Nat :=
match n with
| 0 => 0
| n + 1 => f (n + 1)
```
will show the error with squiggly lines under `f (n + 1)`, and not at
`def f`.
`simp` was previously swallowing runtime exceptions and masking an
issue with this example.
`runT` is defined by well-founded recursion, but reducing the ground
term `runT x` takes a long time when `decide := true`.
Remark PR #2722 changes the `decide` default value to `false`.
When `decide := true`, we should probably have better diagnostics /
error messages for this kind of situation.
This is the same flag that the C test uses. Previously this was hidden
in the Lean compiler itself but now that the optimization pass is phased
out of the compiler we need to put it here.
Co-authored-by: Henrik Böving <hargonix@gmail.com>
The notation `a ∈ as` for Arrays was previously only defined with
`DecidableEq` on the elements, for (apparently) no good reason. This
drops this requirements (by using `a ∈ as.data`), and simplifies a bunch
of proofs by simply lifting the corresponding proof from lists.
Also, `sizeOf_lt_of_mem` was defined, but not set up to be picked up by
`decreasing_trivial` in the same way that the corresponding List lemma
was set up, so this adds the tactic setup.
The definition for `a ∈ as` is intentionally not defeq to `a ∈ as.data`
so that the termination tactics for Arrays don’t spuriously apply when
recursing through lists.
This commit also removes parameter `simpleReduce` from discrimination
trees, and take WHNF configuration options.
Reason: it is more dynamic now. For example, the simplifier
will be able to use different configurations for discrimination tree insertion
and retrieval. We need this feature to address issues #2669 and #2281
This commit also removes the dead Meta.Config field `zetaNonDep`.
Before, Lean would simply emit the message "tag not found". With this
change, it also tells the user what they could have written that would
be accepted.
* fix: make XML parser handle trailing whitespace in opening tags
* fix: make XML parser handle comments correctly
---------
Co-authored-by: György Kurucz <me@kuruczgy.com>
