This PR modifies `#eval e` to elaborate `e` with section variables in
scope. While evaluating expressions with free variables is not possible,
this lets `#eval` give a better error message than "unknown identifier."
Example:
```lean
section
variable (n : Nat)
/-- error: Cannot evaluate, contains free variable `n` -/
#guard_msgs in #eval n
end
```
The error is localized to `#eval`. It would be more friendly if the
error were to be placed on uses of free variables.
[Zulip
discussion](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/Unknown.20identifier.20error.20messages.20for.20.60.23eval.60/near/560864544)
This PR changes the elaboration of the `structure`/`class` commands so
that default values have later fields in context as well. This allows
field defaults to depend on fields that come both before and after them.
While this was already the case for inherited fields to some degree, it
now applies uniformly to all fields. Additionally, when elaborating the
default value for a field, all fields that depend on it are cleared from
the context to avoid situations where the default value depends on
itself.
This addresses an issue reported by Aaron Liu [on
Zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/default.20structure.20values.20can.20depend.20on.20themselves/near/578014370).
This PR adds a warning to any `def` of class type that does not also
declare an appropriate reducibility.
The warning check runs after elaboration (checking the actual
reducibility status via `getReducibilityStatus`) rather than
syntactically checking modifiers before elaboration. This is necessary
to accommodate patterns like `@[to_additive (attr :=
implicit_reducible)]` in Mathlib, where the reducibility attribute is
applied during `.afterCompilation` by another attribute, and would be
missed by a purely syntactic check.
---------
Co-authored-by: Paul Reichert <6992158+datokrat@users.noreply.github.com>
Co-authored-by: Kim Morrison <kim@tqft.net>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This PR sets up the new integrated test/bench suite. It then migrates
all benchmarks and some related tests to the new suite. There's also
some documentation and some linting.
For now, a lot of the old tests are left alone so this PR doesn't become
even larger than it already is. Eventually, all tests should be migrated
to the new suite though so there isn't a confusing mix of two systems.
