tree a79a26715c77f8a03182b6bdc81f939f98791e67
parent 2be20f84ee303b521d4f6c7deb0813d78d7e6945
author Marcel van Lohuizen <mpvl@golang.org> 1608289745 +0100
committer Marcel van Lohuizen <mpvl@golang.org> 1609606817 +0000

internal/core: reimplementation of closedness algorithm

Note: there are considerably more test lines, because
there is a) more position information, and b) there are
more tests. Insofar tests have been removed, it is because
the relevant code no longer exits.

So effectively, there are about 500 lines less code
related to closedness as a result of this change!

- Unify and UnifyAccept do all closedness checking wrt
  the parent locally. The AddVertex and UnifyAccept have
  been removed from eval.
- The old fieldSet is replaced with precomputed values in
  StructLit.
- Most optional and closedness logic has either been
  removed or moved from package eval to package adt.
- Instead of a separate Structs slice and closedness information
  there is now just a StructInfo slice with integrated CloseInfo.
- The Acceptor interface has been removed.
- A new algorithm computes closedness bottom up, instead
  of top-down. See closed.go in ADT for details.
- Recorded about a 15% reducing in running time, memory is
  of the same order.

Note that this removes many optimizations of the previous
implementation. Some of these (and others) could be added
later.

Fixes #599
Fixes #618

Change-Id: If6eec0b915b96067bcc4778bf63707827054b4d1
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/7985
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>