facebook/flow v0.177.0 on GitHub

Likely to cause new Flow errors:

Fix a bug where refinements should be invalidated when going through multiple control flow branches (thanks @gnprice)
Make catch parameters explicitely any typed
Ban object spreads of numbers and strings
Fix a bug that makes Flow consider some function names to have the empty type
Numbers, booleans, and enums are no longer subtypes of the empty interface interface {}
Previously incorrectly missing errors might appear in expressions of the form name === 'literal' and name.prop === 'literal' complaining that literal is incompatible with the type of name or name.prop.
Update input type of Object.{values,entries} to be interface {} rather than $NotNullOrVoid; number and boolean inputs will now error

New Features:

Add codemod to add explicit type arguments to useState when it is called with an empty object. Use with flow codemod annotate-use-state
Continue type checking files with indeterminate module types.

Notable bug fixes:

Do not add further errors when we already errored on the illegal reassignment.
Flow now checks whether literal is a subtype of expr in expr === literal, regardless of whether expr === literal can be applied as a refinement
Fix a crash when deleting a file or saving a file with parse errors in certain circumstances
Fix a rare crash when files are deleted during rechecks
Fix a parser bug that allowed missing commas between object properties (regression in 0.175.0)

Parser:

Improve error recovery when in the middle of adding a property to an object type literal

Library Definitions: