Applying a UDA to a File-type variable makes DMD crash

[H. S. Teoh]

On Sat, Dec 20, 2025 at 01:58:50PM +0100, Marcos Cruz via Digitalmars-d wrote:
[...]
> I have been learning and using D for several months, and following the
> forum groups by email.  In fact D has become my language of choice.

Welcome to the D community! :-)


> Some weeks ago I found a strange issue.  The following code makes DMD
> (2.111.0) crash with message "terminated by signal SIGSEGV (Address
> boundary error)", while LDC (1.41.0) and GDC (14.2.0) compile it (I
> use Debian 13.2, x86_64):

Anything that causes the compiler to crash is a compiler bug. Please
report a bug:

	https://github.com/dlang/dmd/issues


> 
> ```D
> 	enum var;
> 	import std.stdio : File;
> 	@var File file = File("tmp", "w");
> ```
[...]

It's probably a bad idea to do this in module global scope, because
std.stdio.File is referenced counted with a dtor that closes the file
upon exiting the scope. Since module global scope never exits, this
probably interacts badly with built-in assumptions about how dtors are
used in structs.  Likely this is what causes the compiler to hit an
internal compiler error.

If you need a globally-accessible File, you should probably initialize
it in main(), or, barring that, in a module static ctor, something like
this:

```
	import std.stdio L File;
	File file;
	/*shared*/ static this() {
		file = File("tmp", "w");
	}
```


T

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