The tests need to run with certain environment variables set that only
cmake really knows and that differ between stages. Cmake could just set
the variables directly when running the tests and benchmarks, but that
would leave no good way to manually run a single benchmark. So cmake
generates some stage-specific scripts instead that set the required
environment variables.
Previously, those scripts were sourced directly by the individual
`run_*` scripts, so the env scripts of different stages would overwrite
each other. This PR changes the setup so they can instead be generated
next to each other. This also simplifies the `run_*` scripts themselves
a bit, and makes `tests/bench/build` less of a hack.
This PR changes all `lean-toolchain` to use relative toolchain paths
instead of `lean4` and `lean4-stage0` identifiers, which removes the
need for manually linking toolchains via Elan.
After this PR, at least Elan 4.2.0 and 0.0.224 of the Lean VS Code
extension will be needed to edit core.
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
This PR improves the error message encountered in the case of a type
class instance resolution failure, and adds an error explanation that
discusses the common new-user case of binary operation overloading and
points to the `trace.Meta.synthInstance` option for advanced debugging.
## Example
```lean4
def f (x : String) := x + x
```
Before:
```
failed to synthesize
HAdd String String ?m.5
Hint: Additional diagnostic information may be available using the `set_option diagnostics true` command.
```
After:
```
failed to synthesize instance of type class
HAdd String String ?m.5
Hint: Type class instance resolution failures can be inspected with the `set_option trace.Meta.synthInstance true` command.
Error code: lean.failedToSynthesizeTypeclassInstance
[View explanation](https://lean-lang.org/doc/reference/latest/find/?domain=Manual.errorExplanation&name=lean.failedToSynthesizeTypeclassInstance)
```
The error message is changed in three important ways:
* Explains *what* failed to synthesize, using the "type class"
terminology that's more likely to be recognized than the "instance"
terminology
* Points to the `trace.Meta.synthInstance` option which is otherwise
nearly undiscoverable but is quite powerful (see also
leanprover/reference-manual#663 which is adding commentary on this
option)
* Gives an error explanation link (which won't actually work until the
next release after this is merged) which prioritizes the common-case
explanation of using the wrong binary operation
This PR updates the styling and wording of error messages produced in
inductive type declarations and anonymous constructor notation,
including hints for inferable constructor visibility updates.
This PR updates the formatting of, and adds explanations for, "unknown
identifier" errors as well as "failed to infer type" errors for binders
and definitions.
It attempts to ameliorate some of the confusion encountered in #1592 by
modifying the wording of the "header is elaborated before body is
processed" note and adding further discussion and examples of this
behavior in the corresponding error explanation.
This PR improves the error messages produced by invalid projections and
field notation. It also adds a hint to the "function expected" error
message noting the argument to which the term is being applied, which
can be helpful for debugging spurious "function expected" messages
actually caused by syntax errors.
---------
Co-authored-by: Joachim Breitner <mail@joachim-breitner.de>
This PR changes how `{...}`/`where` notation ("structure instance
notation") elaborates. The notation now tries to simulate a flat
representation as much as possible, without exposing the details of
subobjects. Features:
- When fields are elaborated, their expected types now have a couple
reductions applied. For all projections and constructors associated to
the structure and its parents, projections of constructors are reduced
and constructors of projections are eta reduced, and also implementation
detail local variables are zeta reduced in propositions (so tactic
proofs should never see them anymore). Furthermore, field values are
beta reduced automatically in successive field types. The example in
[mathlib4#12129](https://github.com/leanprover-community/mathlib4/issues/12129#issuecomment-2056134533)
now shows a goal of `0 = 0` rather than `{ toFun := fun x => x }.toFun 0
= 0`.
- All parents can now be used as field names, not just the subobject
parents. These are like additional sources but with three constraints:
every field of the value must be used, the fields must not overlap with
other provided fields, and every field of the specified parent must be
provided for. Similar to sources, the values are hoisted to `let`s if
they are not already variables, to avoid multiple evaluation. They are
implementation detail local variables, so they get unfolded for
successive fields.
- All class parents are now used to fill in missing fields, not just the
subobject parents. Closes#6046. Rules: (1) only those parents whose
fields are a subset of the remaining fields are considered, (2) parents
are considered only before any fields are elaborated, and (3) only those
parents whose type can be computed are considered (this can happen if a
parent depends on another parent, which is possible since #7302).
- Default values and autoparams now respect the resolution order
completely: each field has at most one default value definition that can
provide for it. The algorithm that tries to unstick default values by
walking up the subobject hierarchy has been removed. If there are
applications of default value priorities, we might consider it in a
future release.
- The resulting constructors are now fully packed. This is implemented
by doing structure eta reduction of the elaborated expressions.
- "Magic field definitions" (as reported [on
Zulip](https://leanprover.zulipchat.com/#narrow/channel/113489-new-members/topic/Where.20is.20sSup.20defined.20on.20submodules.3F/near/499578795))
have been eliminated. This was where fields were being solved for by
unification, tricking the default value system into thinking they had
actually been provided. Now the default value system keeps track of
which fields it has actually solved for, and which fields the user did
not provide. Explicit structure fields (the default kind) without any
explicit value definition will result in an error. If it was solved for
by unification, the error message will include the inferred value, like
"field 'f' must be explicitly provided, its synthesized value is v"
- When the notation is used in patterns, it now no longer inserts fields
using class parents, and it no longer applies autoparams or default
values. The motivation is that one expects patterns to match only the
given fields. This is still imperfect, since fields might be solved for
indirectly.
- Elaboration now attempts error recovery. Extraneous fields log errors
and are ignored, missing fields are filled with `sorry`.
This is a breaking change, but generally the mitigation is to remove
`dsimp only` from the beginnings of proofs. Sometimes "magic fields"
need to be provided — four possible mitigations are (1) to provide the
field, (2) to provide `_` for the value of the field, (3) to add `..` to
the structure instance notation, (4) or decide to modify the `structure`
command to make the field implicit. Lastly, sometimes parent instances
don't apply when they should. This could be because some of the provided
fields overlap with the class, or it could be that the parent depends on
some of the fields for synthesis — and as parents are only considered
before any fields are elaborated, such parents might not be possible to
use — we will look into refining this further.
There is also a change to elaboration: now the `afterTypeChecking`
attributes are run with all `structure` data set up (e.g. the list of
parents, along with all parent projections in the environment). This is
necessary since attributes like `@[ext]` use structure instance
notation, and the notation needs all this data to be set up now.
This is a major refactor of Lake's build code. The key changes:
* **Job Registration**: Significant build jobs are now registered by
build functions. The DSL inserts this registration automatically into
user-defined targets and facets, so this change should require no
end-user adaption. Registered jobs are incrementally awaited by the main
build function and the progress counter now indicates how many of these
jobs are completed and left-to-await. On the positive side, this means
the counter is now always accurate. On the negative side, this means
that jobs are displayed even if they are no-ops (i.e., if the target is
already up-to-date).
* **Log Retention**: Logs are now part of a Lake monad's state instead
of being eagerly printed. As a result, build jobs retain their logs.
Using this change, logs are are now always printed after their
associated caption (e.g., `[X/Y] Building Foo`) and are not arbitrarily
interleaved with the output of other jobs.
* **Simplify the build monad stack**: Previously, there was a lot of
confused mixing between the various build monads in the codebase (i.e.,
`JobM`, `ScedulerM`, `BuildM`, `RecBuildM`, and `IndexBuildM` ). This
refactor attempts to make there use more consistent and straightforward:
* `FetchM` (formerly `IndexBuildM`) is the top-level build monad used by
targets and facets and is now uniformly used in the codebase for all
top-level build functions.
* `JobM` is the monad of asynchronous build jobs. It is more limited
than `FetchM` due to the fact that the build cache can not be modified
asynchronously.
* `SpawnM` (formerly `SchedulerM`) is the monad used to spawn build
jobs. It lifts into `FetchM`.
* `RecBuildM` and `CoreBuildM` (formerly `BuildM`) have been relegated
to internal details of how `FetchM` / `JobM` are implemented / run and
are no longer used outside of that context.
* **Pretty progress.** Build progress (e.g., `[X/Y] Building Foo`) is
now updated on a single line via ANSI escape sequences when Lake is
outputting to a terminal. Redirected Lake output still sees progress on
separate lines.
* **Warnings-as-error option.** Adds a `--wfail` option to Lake that
will cause a build to fail if Lake logs any warnings doing a build.
Unlike some systems, this does not convert warnings into errors and it
does not abort jobs which log warnings. Instead, only the top-level
build fails.
* **Build log cache.** Logs from builds are now cached to a file and
replayed when the build is revisited. For example, this means multiple
runs of a `--wfail` Lean build (without changes) will still produce the
same warnings even though there is now an up-to-date `.olean` for the
module.
Closes#2349. Closes#2764.
