fixes#24806
Blocks don't merge symbols that are used before destruction to the
parent scope, which causes `wasMoved; destroy` to elide incorrectly
(cherry picked from commit 73aeac81d1)
* implement case for cstring
for now just converts to string on C backend
* custom implementation for cstring
* remove leftover
* revert even more
* add nil + fix packages weird variant literal bug
* update docs
--expandArc
```
var
a
b
a = matrix(5, 5, 1.0)
b = matrix(5, 5, 2.0)
`=sink`(b, -
let blitTmp = b
wasMoved(b)
blitTmp +
a)
`=destroy`(b)
`=destroy`(a)
```
* WIP: an optimizer for ARC
* do not optimize away destructors in 'finally' if unstructured control flow is involved
* optimized the optimizer
* minor code cleanup
* first steps to .cursor inference
* cursor inference: big steps to a working solution
* baby steps
* better .cursor inference
* new feature: expandArc for easy inspection of the AST after ARC transformations
* added topt_cursor test
* adapt tests
* cleanups, make tests green
* optimize common traversal patterns
* moved test case
* fixes .cursor inference so that npeg compiles once again
* cursor inference: more bugfixes
Co-authored-by: Clyybber <darkmine956@gmail.com>
