Getting action on your favorite D issues

[Joseph Rushton Wakeling]

On Saturday, 6 June 2020 at 15:16:06 UTC, ag0aep6g wrote:
> But Walter agrees with you: Using a void value shouldn't 
> actually have undefined behavior; it should just be an 
> arbitrary value. Which is why he has an open pull request to 
> change the spec:
> https://github.com/dlang/dlang.org/pull/2260

Reading that PR, one comment stood out:

> The fact that the compilers don't define the behavior doesn't 
> make it undefined according to the language spec

Which makes me ask: what _does_ "undefined behaviour" mean 
according to the D language spec?

I'm not sure that the spec actually gives a definition: it 
certainly (in the Introduction) starts talking about things that 
_result_ in undefined behaviour, without ever first saying what 
undefined behaviour is.