ldc2 shortened methods

[VadimkaG]

Tell me what I'm doing wrong?

$ cat dub.json

{
	"authors": [
		"Vadimka"
	],
	"copyright": "Copyright © 2024, Vadimka",
	"dependencies": {
		"godot-dlang": "~>0.7.0"
	},
	"description": "godot game",
	"dflags": [
		"-preview=shortenedMethods"
	],
	"license": "proprietary",
	"name": "battlenauts",
	"targetType": "dynamicLibrary"
}

$ dub build --force

Performing "debug" build using /usr/bin/ldc2 for x86_64.
godot-dlang:util 0.7.0: building configuration "library"...
utf_bc 0.2.1: building configuration "library"...
godot-dlang 0.7.0: building configuration "default"...
Running pre-build commands...
../../.dub/packages/godot-dlang-0.7.0/godot-dlang/src/godot/variant.d(716,43): Error: => shortened method not enabled, compile with compiler switch `-preview=shortenedMethods`
../../.dub/packages/godot-dlang-0.7.0/godot-dlang/src/godot/variant.d(718,43): Error: => shortened method not enabled, compile with compiler switch `-preview=shortenedMethods`
/usr/bin/ldc2 failed with exit code 1.

$ ldc2 --version

LDC - the LLVM D compiler (1.30.0):
  based on DMD v2.100.1 and LLVM 14.0.6
  built with LDC - the LLVM D compiler (1.30.0)
  Default target: x86_64-pc-linux-gnu
  Host CPU: goldmont

[selcukcukur]

@VadimkaG The error you’re hitting isn’t about your dub.json itself — the problem is that the godot-dlang package uses the shortened methods preview feature (=> shorthand), but your build isn’t actually compiling with that preview flag enabled.

A couple of key points:

• In dub.json, you added "dflags": ["-preview=shortenedMethods"].
• However, dub only applies dflags to your own target. Dependencies (like godot-dlang) don’t inherit those flags automatically.
• That’s why you see the error inside godot/variant.d: it’s being compiled without the preview flag.

How to fix it

You need to make sure the preview flag is passed to all packages, not just your own:

1. Use buildRequirements in dub.json

   "buildRequirements": ["previewShortenedMethods"]

   This tells dub to apply the preview feature globally, including dependencies.

2. Or set DFLAGS environment variable before building:

   export DFLAGS="-preview=shortenedMethods"
   dub build --force

   That way every compilation unit gets the flag.

3. Alternative: If you only want it for your project, you’d need to patch godot-dlang to add the flag in its own package config, but usually the global requirement is simpler.