spack:
- Optimize resolver
swc_bunder:
- Parallize merging of reexports
- Remove useless `clone`s
swc_ecma_utils:
- Migrate DropSpan to VisitMut
swc_ecma_transforms:
- Migrate simple transforms to VisitMut
- Ignore types to reduce binary size
- Hide actual types so that we can optimize it in future without breaking change
swc_visit:
- Apply transforms for vector in-place
- Apply transforms for box in-place
Handle variable infection in the block scoping pass.
i.e. In the code below, v is 'infected' by i.
```js
var functions = [];
for (let i = 0; i < 10; i++) {
let v = i;
functions.push(function() {
return v;
});
}
functions[0]() // should print 0
```
Closes#609.
