Hello,
I am having this error very often lately when i compile my vibe.d app
with DUB using dmd(default). My project is quite large and it will
become much larger.

Assertion failed: (0), function rehash_x, file ztc/aa.c, line 423.
Error: DMD compile run failed with exit code -6

Full exception: object.Exception@source/dub/compilers/dmd.d(169): DMD 
compile run failed with exit code -6
----------------
5   dub                                 0x0000000103a12437 pure @safe 
bool std.exception.enforce!(bool).enforce(bool, lazy const(char)[], 
immutable(char)[], ulong) + 107
6   dub                                 0x00000001039c407f void 
dub.compilers.dmd.DmdCompiler.invoke(const(dub.compilers.compiler.BuildSettings), 
const(dub.compilers.compiler.BuildPlatform)) + 883
7   dub                                 0x00000001039cd1a9 void 
dub.generators.build.BuildGenerator.generateProject(dub.generators.generator.GeneratorSettings) 
+ 3013
8   dub                                 0x000000010399ea6c void 
dub.dub.Dub.generateProject(immutable(char)[], 
dub.generators.generator.GeneratorSettings) + 160
9   dub                                 0x0000000103992f55 _Dmain + 6773
10  dub                                 0x0000000103a771b1 void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).runAll().void __lambda1() + 33
11  dub                                 0x0000000103a770fd void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) + 45
12  dub                                 0x0000000103a7715d void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).runAll() + 45
13  dub                                 0x0000000103a770fd void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) + 45
14  dub                                 0x0000000103a77079 _d_run_main + 449
15  dub                                 0x0000000103993162 main + 34
16  libdyld.dylib                       0x00007fff8f0287e1 start + 0
17  ???                                 0x0000000000000002 0x0 + 2

I found this:
http://d.puremagic.com/issues/show_bug.cgi?id=8596

Build with --build=release is giving no errors.

With rdmd i get: Undefined symbols for architecture x86_64: Linker error.
(Now that i am writing this rdmd compiled with no errors, without me
changing anything in the project)

I would be thankful for some advice, i am new into programming and i
don't have very deep knowledge about how exactly compilers work etc.