@facebook-github-bot facebook-github-bot released this Oct 11, 2018 · 198 commits to master since this release

Assets 7

Likely to cause new Flow errors:

  • Fixed a bug where type precision was lost at module boundaries

Notable bug fixes:

  • Prevented an exponential blowup when union types flow into "maybe" (?T) or "optional" (essentially T | void) types
  • Allowed {p:T} to be a subtype of $Shape<{+p:T}>


  • Fixed exception when using --traces
  • Changed --verbose to not log while loading flowlibs by default; pass --verbose-flowlibs to override
  • Added ability for LSP clients to cancel previously-sent commands
  • Improved location of diagnostics via LSP while typing
  • Fixed LSP textDocument/definition response when there are no results (prevents bogus jump-to-definition inside comments, for example)
  • Limited number of errors returned via LSP to 200, to improve Nuclide and Visual Studio performance
  • Fixed an exception when attempting to focus a file that Flow ignored

Library definition changes:

  • Added ResizeObserver declarations
  • Added missing net$Server.listening property
  • Added process.cpuUsage()


  • Fixed export default async function to be a FunctionDeclaration not a FunctionExpression
  • Made instance properties named 'constructor' a syntax error