Failed with --combined and DMD

[9il]

The codebase is private
dub -b ddox --combined

Performing "debug" build using /Library/D/dmd/bin/dmd for x86_64.
hyphenate 1.1.1: target for configuration "library" is up to date.
libdparse 0.7.1: target for configuration "library" is up to date.
diet-ng 1.4.4: target for configuration "library" is up to date.
taggedalgebraic 0.10.9: target for configuration "library" is up to date.
eventcore 0.8.27: target for configuration "kqueue" is up to date.
stdx-allocator 2.77.0: target for configuration "library" is up to date.
vibe-core 1.4.0-alpha.1: target for configuration "kqueue" is up to date.
vibe-d:utils 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:data 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:crypto 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:stream 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:textfilter 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:inet 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:tls 0.8.3-alpha.4: target for configuration "openssl" is up to date.
vibe-d:http 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:web 0.8.3-alpha.4: target for configuration "library" is up to date.
ddox 0.16.10: target for configuration "application" is up to date.
To force a rebuild of up-to-date targets, run again with --force.
Running ../../../.dub/packages/ddox-0.16.10/ddox/ddox filter --min-protection=Protected --ex mir. --ex std. --ex asdf docs.json
Reading doc file...
Parsing JSON...
Filtering modules...
Warning: Cannot add documented unit test __unittest_L21_C1 to... , which is not documented.
Warning: Cannot add documented unit test __unittest_L38_C1 to adjuster, which is not documented.
Warning: Cannot add documented unit test __unittest_L59_C1 to adjuster, which is not documented.
Warning: Cannot add documented unit test __unittest_L82_C1 to adjuster, which is not documented.
Warning: Cannot add documented unit test __unittest_L103_C1 to adjuster, which is not documented.
Warning: Cannot add documented unit test __unittest_L123_C1 to adjuster, which is not documented.
Writing filtered docs...
Performing "debug" build using /Library/D/dmd/bin/dmd for x86_64.
hyphenate 1.1.1: target for configuration "library" is up to date.
libdparse 0.7.1: target for configuration "library" is up to date.
diet-ng 1.4.4: target for configuration "library" is up to date.
taggedalgebraic 0.10.9: target for configuration "library" is up to date.
eventcore 0.8.27: target for configuration "kqueue" is up to date.
stdx-allocator 2.77.0: target for configuration "library" is up to date.
vibe-core 1.4.0-alpha.1: target for configuration "kqueue" is up to date.
vibe-d:utils 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:data 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:crypto 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:stream 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:textfilter 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:inet 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:tls 0.8.3-alpha.4: target for configuration "openssl" is up to date.
vibe-d:http 0.8.3-alpha.4: target for configuration "library" is up to date.
vibe-d:web 0.8.3-alpha.4: target for configuration "library" is up to date.
ddox 0.16.10: target for configuration "application" is up to date.
To force a rebuild of up-to-date targets, run again with --force.
Running ../../../.dub/packages/ddox-0.16.10/ddox/ddox serve-html --navigation-type=ModuleTree docs.json --web-file-dir=/Users/9il/.dub/packages/ddox-0.16.10/ddox/public
Reading doc file...
Parsing JSON...
Parsing docs...
std.json.JSONException@std/json.d(1394): Got JSON of type undefined, expected string.
----------------
4   ddox                                0x00000001012287fa const pure @safe void vibe.data.json.Json.checkType!(immutable(char)[]).checkType(immutable(char)[]) + 278
5   ddox                                0x00000001012286cb inout @property @trusted inout(immutable(char)[]) vibe.data.json.Json.get!(immutable(char)[]).get() + 31
6   ddox                                0x000000010137c2bc ddox.entities.Declaration ddox.parsers.jsonparser.Parser.parseDecl(vibe.data.json.Json, ddox.entities.Entity) + 72
7   ddox                                0x000000010137c106 int ddox.parsers.jsonparser.Parser.parseDeclList(vibe.data.json.Json, ddox.entities.Entity).__foreachbody3(ref vibe.data.json.Json) + 90
8   ddox                                0x00000001015a3fd7 int vibe.data.json.Json.opApply(scope int delegate(ref vibe.data.json.Json)) + 159
9   ddox                                0x000000010137c09a ddox.entities.Declaration[] ddox.parsers.jsonparser.Parser.parseDeclList(vibe.data.json.Json, ddox.entities.Entity) + 78
10  ddox                                0x000000010137d024 ddox.entities.CompositeTypeDeclaration ddox.parsers.jsonparser.Parser.parseCompositeDecl(vibe.data.json.Json, ddox.entities.Entity) + 712
11  ddox                                0x000000010137c520 ddox.entities.Declaration ddox.parsers.jsonparser.Parser.parseDecl(vibe.data.json.Json, ddox.entities.Entity) + 684
12  ddox                                0x000000010137c106 int ddox.parsers.jsonparser.Parser.parseDeclList(vibe.data.json.Json, ddox.entities.Entity).__foreachbody3(ref vibe.data.json.Json) + 90
13  ddox                                0x00000001015a3fd7 int vibe.data.json.Json.opApply(scope int delegate(ref vibe.data.json.Json)) + 159
14  ddox                                0x000000010137c09a ddox.entities.Declaration[] ddox.parsers.jsonparser.Parser.parseDeclList(vibe.data.json.Json, ddox.entities.Entity) + 78
15  ddox                                0x000000010137aef3 void ddox.parsers.jsonparser.Parser.parseModuleDecls(vibe.data.json.Json, ddox.entities.Package) + 583
16  ddox                                0x000000010137ac9f int ddox.parsers.jsonparser.parseJsonDocs(vibe.data.json.Json, ddox.entities.Package).__foreachbody3(ref vibe.data.json.Json) + 91
17  ddox                                0x00000001015a3fd7 int vibe.data.json.Json.opApply(scope int delegate(ref vibe.data.json.Json)) + 159
18  ddox                                0x000000010137ac2d ddox.entities.Package ddox.parsers.jsonparser.parseJsonDocs(vibe.data.json.Json, ddox.entities.Package) + 89
19  ddox                                0x000000010135f53c ddox.entities.Package ddox.main.parseDocFile(immutable(char)[], ddox.settings.DdoxSettings) + 168
20  ddox                                0x000000010135e1ad int ddox.main.setupGeneratorInput(ref immutable(char)[][], out ddox.settings.GeneratorSettings, out ddox.entities.Package) + 777
21  ddox                                0x000000010135dba2 int ddox.main.cmdServeHtml(immutable(char)[][]) + 118
22  ddox                                0x000000010135d9a9 int ddox.main.ddoxMain(immutable(char)[][]) + 301
23  ddox                                0x00000001012237bf _Dmain + 31
24  ddox                                0x00000001015cf037 void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).runAll().__lambda1() + 39
25  ddox                                0x00000001015ceec7 void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).tryExec(scope void delegate()) + 31
26  ddox                                0x00000001015cefa2 void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).runAll() + 138
27  ddox                                0x00000001015ceec7 void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).tryExec(scope void delegate()) + 31
28  ddox                                0x00000001015cee35 _d_run_main + 485
29  ddox                                0x00000001012237e9 main + 33
30  libdyld.dylib                       0x00007fff7d479014 start + 0
31  ???                                 0x0000000000000004 0x0 + 4
Program exited with code 1