meta/flow v0.171.0

on GitHub

Likely to cause new Flow errors:

• Disallow duplicate member names in classes.
• Error if an interface is imported as a value.
• The experimental.new_merge option becomes true by default. This is an internal change in the way file signatures are computed, but may cause new [invalid-exported-annotation] errors when a file exports types that include certain kinds of complex operations, such as projections over complex utility types like $ObjMap. These errors can be fixed by replacing these complex types with simpler ones. In certain cases, the newly added $KeyMirror and $ObjMapConst types (that are exempt of this restriction) can be used instead.

Notable bug fixes:

• Fix Watchman file watcher on Windows when an include path doesn't exist.
• Fix a parse error when a newline appears after a class method definition's name.

Parser:

• Add support for parsing logical assignment operators (thanks @strub).
• Fix compliance with estree: export * as x from 'y' is now an ExportAllDeclaration with an exported key.
• Permanently enable parsing of nullish coalescing, and remove the esproposal_nullish_coalescing option.
• Permanently enable parsing of optional chaining, and remove the esproposal_optional_chaining option.
• Permanently enable parsing of class static fields, and remove the esproposal_class_static_fields option.
• Permanently enable parsing of class instance fields, and remove the esproposal_class_instance_fields option.

Library Definitions:

• Make some options parameters in node's fsPromises optional.