Linker error

[Steven Schveighoffer]

On 1/21/19 3:37 PM, Jerry wrote:
> Hello, I am trying to compile a 1 year old project of mine which uses 
> htmld and vibed. But I get this weird linker error which does not make 
> any sense to me atleast. I am using Windows 7 and dub.
> 
> htmld 0.3.6: target for configuration "library" is up to date.
> taggedalgebraic 0.10.12: target for configuration "library" is up to date.
> eventcore 0.8.40: target for configuration "winapi" is up to date.
> stdx-allocator 2.77.5: target for configuration "library" is up to date.
> vibe-core 1.5.0: target for configuration "winapi" is up to date.
> vibe-d:utils 0.8.4: target for configuration "library" is up to date.
> vibe-d:data 0.8.4: target for configuration "library" is up to date.
> mir-linux-kernel 1.0.1: target for configuration "library" is up to date.
> vibe-d:crypto 0.8.4: target for configuration "library" is up to date.
> diet-ng 1.5.0: target for configuration "library" is up to date.
> vibe-d:stream 0.8.4: target for configuration "library" is up to date.
> vibe-d:textfilter 0.8.4: target for configuration "library" is up to date.
> vibe-d:inet 0.8.4: target for configuration "library" is up to date.
> vibe-d:tls 0.8.4: target for configuration "openssl-mscoff" is up to date.
> vibe-d:http 0.8.4: target for configuration "library" is up to date.
> vibe-d:mail 0.8.4: target for configuration "library" is up to date.
> vibe-d:mongodb 0.8.4: target for configuration "library" is up to date.
> vibe-d:redis 0.8.4: target for configuration "library" is up to date.
> vibe-d:web 0.8.4: target for configuration "library" is up to date.
> vibe-d 0.8.4: target for configuration "vibe-core" is up to date.
> my_stuff ~master: building configuration "updater-local"...
> Linking...
> vibe-d_web.lib(common.obj) : warning LNK4255: library contain multiple 
> objects of the same name; lin
> king object as if no debug info
> eventcore.lib(driver.obj) : warning LNK4255: library contain multiple 
> objects of the same name; link
> ing object as if no debug info
> eventcore.lib(driver.obj) : warning LNK4255: library contain multiple 
> objects of the same name; link
> ing object as if no debug info
> eventcore.lib(core.obj) : warning LNK4255: library contain multiple 
> objects of the same name; linkin
> g object as if no debug info
> my_stuff.obj : error LNK2019: unresolved external symbol 
> _D60TypeInfo_xS4html3dom__T15ChildrenForwar
> dTCQBfQBd4NodeVnnZQBi6__initZ referenced in function 
> _D8typecons__T11ThrowOnNullTS4html3dom__T15Chil
> drenForwardTCQBfQBd4NodeVnnZQBiZQCn9__xtoHashFNbNeKxSQDu__TQDoTQDeZQDwZm
> ..dub\build\updater-local-debug-windows-x86_64-dmd_2083-F0ADCB72FF986B7D6354817AF1E3A045\my_stuff.exe 
> 
>   : fatal error LNK1120: 1 unresolved externals
> Error: linker exited with status 1120
> dmd failed with exit code 1.
> 
> I tried to find the typecons.ThrowOnNull thing in the standard library 
> but that one does not exist. So I am pretty confused about what is going 
> on here.
> 
> Thank you.

I had a similar problem that I fixed myself actually last dconf:

https://issues.dlang.org/show_bug.cgi?id=17968

This looks almost identical as the issue was in the generated xtoHash 
function.

What version of the compiler are you using? My issue was fixed in 
2.080.1, and then a followup fix in 2.081.1.

-Steve