Ruby

Box: skip checking the current box is the root box

Because checking the current box is not a cheap process.

Add 4.0 to the spec_guards workflow

Update ruby/setup-ruby action to v1.276.0

Box: allocate classes as boxable when it happens in the root box

Without this change, classes (including iclass) are allocated
as un-boxable classes after initializing user boxes (after starting
script evaluation). Under this situation, iclasses are created as...

[ruby/prism] Optimize ruby visitor

compact_child_nodes allocates an array. We can skip that step by simply yielding the nodes.

Benchmark for visiting the rails codebase:

require "prism"
require "benchmark/ips"

files = Dir.glob("../rails/**/*.rb")...

[ruby/prism] Report missing end errors at opening token

This commit adds an expect1_opening function that expects a token and
attaches the error to the opening token location rather than the current
position. This is useful for errors about missing closing tokens, where...

[ruby/prism] Add unterminated construct tests

https://github.com/ruby/prism/commit/166764f794

Implement moving Immix in MMTk

This commit implements moving Immix in MMTk, which allows objects to move
in the GC.

The performance of this implementation is not yet amazing. It is very
similar to non-moving Immix in many of them and slightly slower in others....

Add rb_gc_move_obj_during_marking

Add rb_gc_register_pinning_obj