I would like to talk more details of #10339 than I did usually because it is an interesting bug: It is an issue that, on the surface, the object-rest-spread should be blamed but after digging you would find that it comes from block-scoping which seems completely unrelated.

I have simplified the OP's snippet a bit

for (const {foo, ...bar} of {}) {
  () => foo;
  bar;
}

The minimum configuration to reproduce this bug is

{
  "plugins": ["transform-block-scoping", ["proposal-object-rest-spread", { "loose": true }]]
}

note that the plugin order matters here. Theoretically a loose approximation of this configuration would be a two-pass transformation: First transform with transform-block-scoping and then transform the intermediate result with proposal-object-rest-spread. The Babel REPL works good on two-pass transformation, which means there must be something wrong after the block-scoping transforms. Something that does not touch the syntax but the abstract metadata.

The error in #10339 comes from

The block-scoping transform will try to wrap the loop body into a closure once a let reference is used inside a function expressions in the loop body. Which means

for (const {foo, ...bar} of {}) {
  () => foo;
  bar;
}

will be transformed to

var _loop = function (foo, bar) {
  () => foo;
  bar;
};

for (var { foo, ...bar } of qux) {
  _loop(foo, bar);
}

since foo is inside an arrow function expression. However, the block-scoping transform incorrectly removes the binding after the loop body is wrapped -- maybe because we tend to feel it is useless since the whole loop body is wrapped in a new scope.

This operation creates dichotomy between the actual code and the abstract syntax tree: The variable declarator is still in our code while its binding information is removed. This error has been hidden for a while until it is luckily detected by object-rest-spread loose mode, which tries to manipulate the code according to the binding information.

In the end, the fix is pretty straightforward: do not remove the binding information and always synchronize code with AST.