there was a check
if !Structural.recArgHasLooseBVarsAt recFnName fixedPrefixSize e then
that would avoid going through `.refineThrough`/`.addArg` for
matcher/casesOn applications. It seems it tries to detect when refining
the motive/param is pointless, but it was too eager, and cause confusion
with, for example, this reasonably reasonable function:
def foo : (n : Nat) → (i : Fin n) → Bool
| 0, _ => false
| 1, _ => false
| _+2, _ => foo 1 ⟨0, Nat.zero_lt_one⟩
decreasing_by simp_wf; simp_arith
In particular, the `GuessLex` code later expects that the (implict)
`PProd.casesOn` in the implementation of `foo._unary` will refine the
paramter, because else the (rather picky) `unpackArg` fails. But it also
prevents this from being provable.
So let's try without this shortcut.
Fixing this also revealed that `withRecApps` wasn’t looking in all
corners
of a matcherApp/casesOnApp.
Fixes#3175
This uses the improved termination_by syntax to give Nat.gcd a cleaner
definition. It removes the last explicit use of WellFounded.fix in Init.
This was also partly motivated by leanprover/std4#520 so that unfold
Nat.gcd gives a sensible definition.
If the current manifest is from unsupported (or has errors), a bare
`lake update` will now discard it and create a new one from scratch
rather than erroring and requiring you to manually delete the manifest.
Lake will produce warnings noting it is ignoring such invalid manifests.
This change
* moves `termination_by` and `decreasing_by` next to the function they
apply to
* simplify the syntax of `termination_by`
* apply the `decreasing_by` goal to all goals at once, for better
interactive use.
See the section in `RELEASES.md` for more details and migration advise.
This is a hard breaking change, requiring developers to touch every
`termination_by` in their code base. We decided to still do it as a
hard-breaking change, because supporting both old and new syntax at the
same time would be non-trivial, and not save that much. Moreover, this
requires changes to some metaprograms that developers might have
written, and supporting both syntaxes at the same time would make
_their_ migration harder.
This introduces `FilePath.addExtension` to take a path that we know has
no prior extension, and append a new extension to it.
As this function is simpler than `FilePath.withExtension`, this change
eagerly replaces uses of the latter with the former, except in a few
cases where stripping the extension really is the right thing to do.
This should fix the bug described at
https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Import.20file.20with.20multiple.20dots.20in.20file.20name/near/404508048,
where `import «A.B».«C.D.lean»` is needed to import `A.B/C.D.lean`.
Closes#2999
---------
Co-authored-by: Mac Malone <tydeu@hatpress.net>
Co-authored-by: Sebastian Ullrich <sebasti@nullri.ch>
To handle delaborating notations that are functions that can be applied
to arguments, extracts the core function application delaborator as a
separate function that accepts the number of arguments to process and a
delaborator to apply to the "head" of the expression.
Defines `withOverApp`, which has the same interface as the combinator of
the same name from std4, but it uses this core function application
delaborator.
Uses `withOverApp` to improve a number of application delaborators,
notably projections. This means Mathlib can stop using `pp_dot` for
structure fields that have function types.
Incidentally fixes `getParamKinds` to specialize default values to use
supplied arguments, which impacts how default arguments are delaborated.
---------
Co-authored-by: Sebastian Ullrich <sebasti@nullri.ch>
Allow `simproc`s to be declared without setting the `[simproc]`
attribute. A `simproc` declaration is function + pattern.
Motivation: allow them to be provided as arguments to `simp` **and** `simp only`.
TODO: track their use in `simp`.
TODO: builtin simprocs
Motivations:
- We can simplify the big mutual recursion and the implementation.
- We can implement the support for `match`-expressions in the `pre` method.
- It is easier to define and simplify `Simprocs`.
The example was looping with the new `simp` reduction strategy. Here
is the looping trace.
```
List.reverseAux (List.reverseAux as []) bs
==> rewrite using reverseAux_reverseAux
List.reverseAux [] (List.reverseAux (List.reverseAux as []) bs)
==> unfold reverseAux
List.reverseAux (List.reverseAux as []) bs
==> rewrite using reverseAux_reverseAux
List.reverseAux [] (List.reverseAux (List.reverseAux as []) bs)
==> ...
```
See new test for example that takes exponential time without new simp
theorems.
TODO: replace auxiliary theorems with simprocs as soon as we implement them.
I was about to to address the TODO
/- TODO: check arity of the given function. If it takes a PSigma as the
last argument,
this function will produce incorrect results. -/
because we now have an arity-observing variant of `decodePackedArg?` in
`unpackArg` in `PackMutual`, and it would be prudent to use it here.
But I first wanted to create a test case that would actually exhibit
this corner case, and failed.
This code was added in 096e4eb6d0 and it had a test case, but not even
that test case seems to be actually using the `decodePackedArg?`
function, neither back then nor now.
Also, mathlib works without this code.
So this seems to be dead code, possibly due to other changes to the
system, and thus can be removed. A strategically place comments points
back to this PR in case we need to resurrect that code.
