This failing test case demonstrates a regression between 7.0.0-beta.38 and
7.0.0-beta.39 in the @babel/plugin-proposal-object-rest-spread package.
I distilled this test case from a larger configuration of plugins in my
application, one of which calls api.traverse.cache.clearScope(). Although
calling clearScope() is an uncommon thing for a plugin to do, it was a
reliable way to reproduce the problem. If I can find other reliable
reproductions, I'll push some additional failing tests to this PR.
Regardless of how common it is, clearing the scope cache should be a safe
operation that only slows down the transform (because scopes have to be
recreated and re-crawled). Crashing due to a spurious duplicate
declaration seems like a bug worth fixing.
My hunch is that [these two lines](eb38ea2b10/packages/babel-plugin-proposal-object-rest-spread/src/index.js (L75-L76))
(which were changed in `7.0.0-beta.39`) are not actually removing the
original rest element as a binding from the enclosing `Scope`, in certain
circumstances, so the new variable declaration ends up colliding with the
old (removed) binding.
Possibly related: #7304 (reported by @julien-f)
* generate typescript types
* improve type generator output
* move generator scripts to scripts/generators
* use new stringifier for generating flow types too
* export summary types
* add support for oneOfNodeOrValueTypes to improve type generation
* export typescript types from top level, and remove module declaration
* generate typescript/flow types and copy typescript types to babel-types/lib as part of make build
* copy flow types to babel-types/lib as part of make build (fix#6839)
* improve typing: Identifier->name should be a string, not any
* avoid destructuring, to support node 4
* update doc generator to share more code, regenerate babel-types readme, pipe all generator output to stdout
* regenerate babel-types readme as part of make build
* improve typing: ClassProperty->key should be Identifier | StringLiteral | NumericLiteral | Expression, not any
* improve typing: optional node properties are nullable, not undefinedable
* improve docs: FlowClassImplements should be ClassImplements
* make ts usage more friendly: when using babel-types api, make optional params | undefined, and when reading nodes keep optional params | null
* rm lib/types.d.ts and lib/types.js in favor of packages/babel-types/lib
* add missing variance node type, address review comments
* add tests for flow variance
* Comment should be a disjoint union of tagged types
* update .flowconfig
