Static type checker for Python

Speed

Pyright is a fast type checker meant for large Python source bases. It can run in a "watch" mode and performs fast incremental updates when files are modified.

Configurability

Pyright supports configuration files that provide granular control over settings. Different "execution environments" can be associated with subdirectories within a source base. Each environment can specify different module search paths, python language versions, and platform targets.

Type Checking Features

PEP 484 type hints including generics
PEP 526 syntax for variable annotations
PEP 544 structural subtyping
PEP 589 typed dictionaries
Type inference for function return values, instance variables, class variables, and globals
Smart type constraints that understand conditional code flow constructs like if/else statements

VS Code Language Features

The VS Code extension supports many time-saving language features including:

Intelligent type completion of keywords, symbols, and import names appears when editing
Import statements are automatically inserted when necessary for type completions
Signature completion tips help when filling in arguments for a call
Hover over symbols to provide type information and doc strings
Find Definitions to quickly go to the location of a symbol's definition
Find References to find all references to a symbol within a code base
Rename Symbol to rename all references to a symbol within a code base
Find Symbols within the current document or within the entire workspace
Organize Imports command for automatically ordering imports according to PEP8 rules
Type stub generation for third-party libraries

Built-in Type Stubs

Pyright includes a recent copy of the stdlib type stubs from Typeshed. It can be configured to use another (perhaps more recent or modified) copy of the Typeshed type stubs. Of course, it also works with custom type stub files that are part of your project.

For more details, refer to the README on the Pyright GitHub site.

Pyright