`reportShadowedImports` doesn't report diagnostics for files that are overriding a `stdlib` module

[StellaHuang95]

Environment data

• Language Server version: 2024.6.1
• OS and version: XXX
• Python version (& distribution if applicable, e.g. Anaconda): XXX

Repro Steps

1. Create a workspace in VSCode
2. Set the "reportShadowedImports": "error" in settings.json
3. Create 2 python files sys.py and mailbox.py

Expected behavior

I am expecting to see 2 diagnostics:

"xxx\folder1\mailbox.py" is overriding the stdlib module "mailbox"
and
"xxx\folder1\sys.py" is overriding the stdlib module "sys"

Actual behavior

Only getting 1 diagnostic:

"xxx\folder1\mailbox.py" is overriding the stdlib module "mailbox"

Only repros with certain stdlib modules such as os, json, sys

[StellaHuang95]

The _buildStdlibCache in importResolver.ts finds all the stdlib modules in typeshed stdlib to return a Set with all the names. sys in typeshed is a directory but not a file, so it doesn't get added in.

[heejaechang]

Repro workspace for investigation:
https://github.com/heejaechang/pylance-repro/tree/main/pylance-issues/5979

[heejaechang]

@StellaHuang95 Thanks for the report.

The original reportShadowedImports diagnostic is no longer present in current Pylance, so the diagnostic-specific part of this report is no longer applicable.

Pylance does still offer a code action to rename files or imports that shadow standard-library modules. We found that this code action was not being offered correctly for this case, and we’ve made a fix so the rename action is offered as expected.

This should be available in the next Pylance release.