@babel/runtime-corejs2

Thanks @Dunqing, @luiscubal, and @samualtnorman for your first PRs!

:eyeglasses: Spec Compliance

• babel-parser

  • Forbid initializerless using (@JLHwung)

• babel-helpers, babel-plugin-proposal-decorators, babel-runtime-corejs3

  • Ensure decorators are callable (@JLHwung)

:bug: Bug Fix

• babel-generator

  • fix: Correctly prints { [key in Bar]? } (@liuxingbaoyu)

  • fix: Correctly generate TSMappedType (@liuxingbaoyu)

• babel-compat-data, babel-plugin-bugfix-firefox-class-in-computed-class-key, babel-preset-env

  • Create bugfix plugin for classes in computed keys in Firefox (@nicolo-ribaudo)

• babel-helper-create-class-features-plugin, babel-plugin-proposal-decorators

  • fix: support mutated outer decorated class binding (@JLHwung)

  • fix: Decorators when super() exists and protoInit is not needed (@liuxingbaoyu)

• babel-plugin-transform-block-scoping

  • fix: Transform scoping for for X in loop (@liuxingbaoyu)

  • fix: Capture let when the for body is not a block (@liuxingbaoyu)

• babel-core, babel-plugin-transform-block-scoped-functions, babel-plugin-transform-block-scoping

  • Fix incorrect function hoisting in some case statements (@luiscubal)