- Make let, const, and class symbols be declared in a block scope.
- Piggy back on existing catch symbol implementation to get block-aware mangling working
- Make sure unused block-scoped declarations can be dropped
- Don't eliminate a block if it has a block-scoped declaration
- Remove silly empty anonymous blocks left over from drop_unused
- AST_Toplevel now gets to call drop_unused too, since block-scoped variables aren't global!
- Don't consider block declarations global
This reverts commit ad18689d92.
Reason for revert: introduce issue #882
Currently, generated sourcemap contains copy of all existing mappings and adds new mappings from uglified code to original one.
However, previous mapping are no longer valid and shouldn't be added.
Running `uglifyjs --verbose --compress --mangle --screw-ie8 class.js`
with
`class.js`:
```
class Foo {
bar() {
}
}
```
Fails with:
```
undefined:4041
return this.definition().unmangleable(options);
TypeError: Cannot read property 'unmangleable' of undefined
at AST_Node.eval [as unmangleable] (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:4041:27)
at Object.eval [as visit] (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:4214:53)
at Object.TreeWalker._visit (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:1493:24)
at AST_Node.DEFNODE._walk (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:415:24)
at AST_Node.eval (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:775:38)
at Object.TreeWalker._visit (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:1497:21)
at AST_Node.DEFNODE._walk (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:774:24)
at eval (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:1303:22)
at Array.forEach (native)
at AST_Node.eval (eval at <anonymous> (/Users/craverod/opensource/panels/panels/node_modules/uglify-js/tools/node.js:22:1), <anonymous>:1302:29)
```
This PR sorts it out (it gives me: `class Foo{bar(){}}`) but it feels like the wrong hack.
I don't know what's best and whether we can even try to mangle the method or not, mainly because
it's the classes' external API and doing so would prevent others from using it outside the minified
source.
Thoughts?
