fix: Inconsistencies in ESM-style imports of accessibility-modified proper...

[arnavnagzirkar]

Summary

Fix for issue #62519.

Issue

Fixes #62519

Issue URL: #62519

Changes

AGENTS.md                                          | 59 +++++++++++-----------
 src/compiler/checker.ts                            |  7 ++-
 .../namedImportFromCjsClassExportAccessibility.ts  | 15 ++++++
 3 files changed, 50 insertions(+), 31 deletions(-)

Testing

• Agent ran relevant tests during development

• Linting checks passed

• Changes are minimal and focused on the issue

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds an accessibility check for named imports from CommonJS export = modules when the export is a class and the imported names map to static class members.

Changes:

• Introduces a new compiler test covering named imports from export = class modules with differing member visibility.
• Updates the checker to validate accessibility for import { … } from "./cjsExportEqualsClass" when those names resolve to class members.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/cases/compiler/namedImportFromCjsClassExportAccessibility.ts	Adds a regression test for importing static class members (public/protected/private) from a CJS export = class.
src/compiler/checker.ts	Adds an accessibility check when resolving named imports against export = module exports that are class members.

Comments suppressed due to low confidence (3)

src/compiler/checker.ts:1

• checkPropertyAccessibilityAtLocation reports diagnostics as a side effect. Calling it from this symbol-resolution path can produce duplicate diagnostics or diagnostics in contexts that only intended to query symbols (e.g., language service queries that reuse checker helpers). Prefer moving the accessibility diagnostic emission into the dedicated import-checking path (where other import diagnostics are produced) and keep this helper focused on returning/resolving symbols.
  src/compiler/checker.ts:1
• The diagnostic location is currently the whole ImportSpecifier node (specifier). To make the error squiggle more precise (and consistent with other property-accessibility errors), pass the imported name node (e.g., name / specifier.name as appropriate) as the location argument so the diagnostic points at the specific inaccessible import (b / c) rather than the entire specifier.
  src/compiler/checker.ts:1
• getTypeOfSymbol(targetSymbol) is called multiple times in this block (also at line 4083). Consider storing it in a local (e.g., const targetType = getTypeOfSymbol(targetSymbol);) and reusing it for both getPropertyOfType(...) and checkPropertyAccessibilityAtLocation(...) to avoid repeated work in hot paths.

[RyanCavanaugh]

#63521 (comment)