fix: preserve nested CJS constructor function names

[proggeramlug]

Summary

• Preserve the declared display name when lowering a nested function declaration to an inline closure. CJS wrappers nest package code, so these declarations are absent from the top-level function name registry.
• Add a CJS import regression that checks both the exported constructor's .name and an instance's constructor.name, along with construction and instanceof.

Fixes #10702.

Verification

• The regression failed on unmodified origin/main: NAMES instead of NAMES Ledger Ledger; construction and instanceof passed.
• The same regression passes with this change on the remote Linux build.
• cargo fmt --all -- --check
• scripts/check_file_size.sh
• git diff --check

Summary by CodeRabbit

• Bug Fixes

  • Preserved declared function names for nested constructors exported by CommonJS modules.
  • Function names are now correctly reflected through function.name and constructor.name, including factory-created instances.
  • Improved compatibility for instanceof checks involving imported CommonJS constructors.

• Tests

  • Added coverage verifying CommonJS constructor names, instance behavior, and returned values.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 8dacc87d-a077-440c-a6bc-b422793d719d

📥 Commits

Reviewing files that changed from the base of the PR and between c7cbc3c and e043e78.

📒 Files selected for processing (3)

• changelog.d/11009-cjs-function-names.md
• crates/perry-hir/src/lower_decl/body_stmt/nested_fn_decl.rs
• crates/perry/tests/issue_10702_cjs_function_name.rs

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📝 Walkthrough

Walkthrough

Changes

Nested constructor name preservation

Layer / File(s)	Summary
Record nested names and validate CommonJS output crates/perry-hir/src/lower_decl/body_stmt/nested_fn_decl.rs, crates/perry/tests/issue_10702_cjs_function_name.rs, changelog.d/11009-cjs-function-names.md	Nested function lowering records the declared name for closure-based functions. An end-to-end CommonJS test verifies name, constructor.name, instanceof, and returned values. The changelog documents the fix.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to e043e

The change preserves constructor names for nested CommonJS exports while retaining construction and instanceof behavior. No merge-blocking risk remains in the supplied review context.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: preserving nested CommonJS constructor function names.
Description check	✅ Passed	The description explains the change, links the related issue, describes the regression coverage, and lists verification commands and results. It does not use separate Changes or Test plan headings and…
Linked Issues check	✅ Passed	The change satisfies #10702. lower_nested_fn_decl records each nested declaration's func_name in ctx.closure_display_names, which preserves the declared name when the declaration lowers to an in…
Out of Scope Changes check	✅ Passed	All changed files support #10702. The HIR change implements name preservation, the integration test verifies the required CJS behavior and existing constructor semantics, and the changelog documents t…

Full details: Docstring Coverage

Explanation

Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files. (1 skipped: 1 unsupported.)

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[proggeramlug]

Landed on main in merge train 265 (#11108), released as v0.5.1648 at 9d26936298.

Cherry-picked from this PR's head e043e7890c and validated as one tree with 15 other PRs — CI 22/22 green, all 6 gap-suite shards. A train rebase gives the commits new SHAs, so GitHub cannot auto-close the source PR; closing by hand.

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