The old code assumes unary minus (`-@`) does not cause any side effect
(including errors). Considering the code like `-nil; nil`, the
assumption was too aggressive.
Previously, the following code did not give the expected result.
```
% bin/mruby -e 'p "%08X" % ~(-1 << 16)'
"..F0000FFFF"
% ruby32 -e 'p "%08X" % ~(-1 << 24)'
"00FFFFFF"
```
For information: this problem arises in the process of folding numbers through optimisation.
Transforms the value of a splat inside a return statement (similar
to an array). For example, `return *nil` should return `nil.to_a`,
while `return *1` should return `[1]`
- mrb_div_int() does integer division in Ruby way (mdiv)
returns mrb_int
- mrb_div_int_value() division with zero div and overflow checks.
returns mrb_value
At the same time, the saving and restoration of unwanted object arenas was removed.
In addition, the common code to extend the pool that existed before has been grouped together and newly established as `lit_pool_extend()`.
Note that previously the variable `i` was updated at that time, but since it is the same as the value at the end of a `for` statement, it has been omitted.
The original catalyst was that `bin/mrbc` with the `MRB_WORD_BOXING` + not `MRB_BOXWORD_NO_FLOAT_TRUNCATE` configuration caused `bin/mrbtest` with the `MRB_NO_BOXING` configuration to fail.
Upon investigation, I concluded that avoiding the creation of temporary objects would prevent the truncation of floating point numbers.
Therefore, this patch also prevents the `rake test` from failing with the following configuration.
```console
% cat test_config.rb
bootstrap_mrbc = nil
MRuby::Build.new do |conf|
conf.toolchain
conf.enable_debug
conf.enable_test
conf.disable_presym
conf.defines << %w(MRB_WORD_BOXING)
#conf.defines << %w(MRB_WORDBOX_NO_FLOAT_TRUNCATE)
gem core: "mruby-bin-mrbc"
gem core: "mruby-kernel-ext"
bootstrap_mrbc = File.join(conf.build_dir, "bin/mrbc")
end
MRuby::Build.new("nobox") do |conf|
conf.toolchain
conf.enable_debug
conf.enable_test
conf.defines << %(MRB_NO_BOXING)
conf.mrbcfile = bootstrap_mrbc
gem core: "mruby-kernel-ext"
end
```
Internal functions can only be called from within the library.
Functions listed in `mruby/internal.h` can be called from:
* core (src/*.c)
* gems (mrbgems/**/*.c)
But not from the application linked with `libmruby`.
I expect this will fix the two problems that "#5640" didn't address.
- It is expected to raise an exception `TypeError`, but it didn't before.
```console
% bin/mruby -e 'p [**1]'
[1]
```
- The variable `h` is expected to keep an empty hash, but it didn't before.
```console
% bin/mruby -e 'h = {}; p(**h, a: 1, b: 2); p h'
{:a=>1, :b=>2}
{:a=>1, :b=>2}
```
Yukihiro "Matz" Matsumoto