pyright

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 487 simpler customization of class creation
• PEP 526 syntax for variable annotations
• PEP 544 structural subtyping
• PEP 561 distributing and packaging type information
• PEP 563 postponed evaluation of annotations
• PEP 570 position-only parameters
• PEP 585 type hinting generics in standard collections
• PEP 586 literal types
• PEP 589 typed dictionaries
• PEP 591 final qualifier
• PEP 593 flexible variable annotations
• PEP 604 complementary syntax for unions
• PEP 612 parameter specification variables
• PEP 613 explicit type aliases
• PEP 635 structural pattern matching
• PEP 646 variadic generics
• PEP 647 user-defined type guards
• PEP 655 required typed dictionary items
• PEP 673 Self type
• PEP 675 arbitrary literal strings
• PEP 681 dataclass transform
• Type inference for function return values, instance variables, class

variables, and globals

• Type guards that understand conditional code flow constructs like

if/else statements

Language Server Integration

Pyright ships as both a command-line tool and a Language Server protocol
server that provides many powerful features that help improve programming
efficiency.

Language Server Features

• 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
• View call hierarchy information — calls made within a function and

places where a function is called

• Organize Imports command for automatically ordering imports according

to PEP8 rules

• Type stub generation for third-party libraries