[Merged by Bors] - fix(Tactic/Convert): support over-applications again

[JovanGerb]

This PR fixes a regression introduced in #38071, which had caused the congruence algorithm of convert to not support over-applications.

I added a test to show this now works again.

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[github-actions]

PR summary d63dfe5806

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

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Declarations diff (regex)

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit d63dfe5).

• +0 new declarations
• −0 removed declarations

No declaration differences.

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No changes to strong technical debt.

No changes to weak technical debt.

Current commit d63dfe5806
Reference commit aea5d67c4f

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[joneugster]

thanks!

maintainer merge

[github-actions]

🚀 Pull request has been placed on the maintainer queue by joneugster.

[ocfnash]

@JovanGerb The PR title and the comment that becomes the commit message seem to contradict each other. Can you please fix this before sending this to master.

Otherwise I trust this is the right move.

bors d+

[mathlib-bors]

✌️ JovanGerb can now approve this pull request until 2026-07-14 15:10 UTC (in 2 weeks). To approve and merge, reply with bors r+. More detailed instructions are available here.

⚠️ This delegation only covers changes within Archive/**, Counterexamples/**, docs/**, DownstreamTest/**, Mathlib/**, MathlibTest/**, widget/**, Archive.lean, Counterexamples.lean, docs.lean, Mathlib.lean; an author commit touching anything else will revoke it. Bors also revokes it if a later push changes too many files for it to check the full list — even if it stays within scope.

[JovanGerb]

bors r+

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Lint style
• ci (staging) / Post-Build Step
• ci (staging) / Post-CI job
• ci (staging) / Build
• ci (staging) / Test and lint