Pragma msg goes out of memory when supplied with large data.

[realhet]

On Wednesday, 21 May 2025 at 14:40:21 UTC, realhet wrote:
> On Wednesday, 21 May 2025 at 14:00:56 UTC, realhet wrote:
> Small program to reproduce.

I'm lucky:
`pragma(msg, "Here comes the big data: ", data);`
With this simple way I managed to put 16MB large data through it 
in no time.
It was new to me that pragma_msg don't care about the actual type 
of data type, it just copies the raw bytes to the stderr as fast 
as it can.

And if I use a high level functional transformation on it, it 
goes terrible slow.
For example the complexity inside text() has a really big penalty 
in Compile Time.

Because of this, I wanted to make a simpler non-functional 
transformation myself:
```d
string transform(string a)
{
	auto b = cast(ubyte[])a.dup;
	foreach(ref ch; b) if(ch=='x') ch = 'y';
	return cast(string)b;
}
```

For my big surprise, with this simple thing I managed to trigger 
that same out of memory 'bug'.

Now I only have one question: Why are these simple looking things 
are so slow in compile time?  I learned that there is a different 
limited runtime environment in compile-time, but I don't 
understand.  Anyone can help with some clues please?