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Questions tagged [pylance]

Pylance is an extension for Visual Studio Code that provides a language server for Python. When applying this tag to your question, consider also tagging it with [visual-studio-code] and/or [python].

Pylance is a language server to support the core Python extension for Visual Studio Code. Its aim is to help developers write Python code better and faster by providing auto-imports, semantic highlighting, built-in reporting of warnings and errors, strict type-checking, and method signatures with type information when displaying the popup Intellisense documentation.

It was first introduced in a post on Microsoft's Python development blog: Announcing Pylance: Fast, feature-rich language support for Python in Visual Studio Code:

To deliver an improved user experience, we’ve created Pylance as a brand-new language server based on Microsoft’s Pyright static type checking tool. Pylance leverages type stubs (.pyi files) and lazy type inferencing to provide a highly-performant development experience. Pylance supercharges your Python IntelliSense experience with rich type information, helping you write better code, faster. The Pylance extension is also shipped with a collection of type stubs for popular modules to provide fast and accurate auto-completions and type checking.

It was made available starting VS Code 1.49 (2020.8.0 (12 August 2020) release).

  1. Expose Pylance setting in python.languageServer. If Pylance extension is not installed, prompt user to install it. (#13122)

Installation is straightforward:

  1. Install the Pylance extension
  2. Configure your settings.json file 
    "python.languageServer": "Pylance",
  3. Open a .py file and the extension should activate

For more information:

465 questions
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VS Code Pylance works slow with much delay

When I try to use the autocomplete using Pylance it is stuck there for some time and After Some time like 3 ~ 5 seconds the pop up with auto-complete shows up Python Language Server is already set to Pylance What I've tried so far. Reinstall Python…
Ayush Shah
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Can I disable type errors from third-party packages in Pylance?

Some of the packages I use don't type hint their code, so when I use them, Pylance keeps telling me that the functions I use have partially unknown types, which is a problem I can't fix. Is there a way to disable such errors?
palapapa
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VS/Pylance warning: import "module" could not be resolved

Hi I am getting the following warning (A squiggly line underneath imports), import "numpy" could not be resolved Pylance(reportMissingModuleSource). There is no issues with executing the code - works fine, just the warning (squiggly line). In the…
imantha
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Import "matplotlib" could not be resolved from source Pylance(reportMissingModuleSource)

whenever I try to import matplotlib or matplotlib.pyplot in VS Code I get the error in the title: Import "matplotlib" could not be resolved from source Pylance(reportMissingModuleSource) or Import "matplotlib.pyplot" could not be resolved from…
Sjotroll
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"at" sign (@) in Python type hints (suggested by Pylance / Pyright)

The July 2022 release of the Python extension for Visual Studio Code introduced "Inlay Type Hints", which automatically suggests return types of functions that don't have an explicit annotation. To enable it, you can set…
scūriolus
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1 answer

Python: "Tuple" is not defined warning

I'm writing a function that returns a tuple and using type annotations. To do so, I've written: def foo(bar) -> Tuple[int, int]: pass This runs, but I've been getting a warning that says: "Tuple" is not defined Pylance report…
dorian.
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2 answers

Pylance does not recognise newly installed pip packages

I am getting the following error while trying to import newly installed packages from pip: Import "" could not be resolved Pylance(reportMissingImports) After I restart VS Code, Pylance seems to then be able to recognise the package. Is…
Harry Stout
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How to configure Microsoft Pylance to not use stub files (.pyi) for django?

I am doing Django development using visual studio code on mac os with microsoft's pylance extension installed. Following is the version specification of my eco system : OS -> MacOS Mojave django -> 3.1.5 visual studio code -> 1.52.1 Microsoft…
Utsav Chokshi
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Is there any way I could get Pylance to automatically hint types on pytest fixture arguments?

Consider the following code: fixtures.py @pytest.fixture def hello_world(): return "Hello world!" And then... basic_tests.py def test_says_hello(hello_world): assert hello_world == "Hello world!" Now the thing is, pylance has no way of…
Tomáš Zato
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VSCode "Import X could not be resolved" even though listed under `help('modules')`

I'm on day 1 of Python and trying to import SciPy into a project. I installed it via pip install on ElementaryOS (an Ubuntu derivative). I have verified it's existence via: $ python >>> help("modules") The exact error I'm getting is: Import…
Seph Reed
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how do I solve the Pylance(reportMissingImports)?

I used pip install fastapi to download it in my virtual environment, in terminal but when I try to import from it it shows up as a missing import.
Ali.A
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How to deal with unknown types of functions/methods from imported modules

I'm wondering what's the best approach to deal with unknown types of functions/methods associated with other modules. Note that I'm using strict mode For example, I have the following: rooms: List[str] =…
Adrian Pop
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3 answers

Pylance in VS Code crashes when adding or deleting cells in a Jupyter notebook

I'm encountering an issue with the Pylance extension in VS Code when working on a Python notebook. Sometimes if I add or delete a cell, the language server crashes and throws the following error: Error: Debug Failure. False expression: Chained file…
Priman Hobser
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vscode pylance type checking does not recognize re imports

When turning on "python.analysis.typeCheckingMode": "strict" or "python.analysis.typeCheckingMode": "basic", .py files containing imports of other modules do not recognize reimports and highlight them with errors: "Flow" is not exported from module…
Mat
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How do i enable code lens support for python in vscode?

I am trying to find code lens support for python in visual studio code. I am having many methods which are not used. Using 'find all references' for each method is time consuming and tedious. If code lens facility there and show number of references…
Samselvaprabu
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