seems like chmgen triggers a bug in std.json

[MartinNowak]

http://nightlies.dlang.org/dmd-newCTFE-2016-12-31/build.html

std.json.JSONException@std\json.d(1300): Found 'y' when expecting 'u'. (Line 1:4166)
----------------
0x00431616 in pure @safe void std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions).error(immutable(char)[]) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(694)
0x00433561 in pure @safe void std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions).checkChar!(false, false).checkChar(char) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(753)
0x00431D9A in @safe void std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions).parseValue(ref std.json.JSONValue) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(970)
0x00431B86 in @safe void std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions).parseValue(ref std.json.JSONValue) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(879)
0x00431AD4 in @safe void std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions).parseValue(ref std.json.JSONValue) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(859)
0x00431B86 in @safe void std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions).parseValue(ref std.json.JSONValue) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(879)
0x004315DA in @safe std.json.JSONValue std.json.parseJSON!(immutable(char)[]).parseJSON(immutable(char)[], int, std.json.JSONOptions) at C:\Users\vagrant\clones\dmd\src\..\..\phobos\std\json.d(997)
0x004034A6 in void chmgen.loadNavigation() at C:\Users\vagrant\clones\dlang.org\chmgen.d(204)
0x004032F2 in _Dmain at C:\Users\vagrant\clones\dlang.org\chmgen.d(170)
0x0043DF03 in D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv
0x0043DEC7 in void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).runAll()
0x0043DDC8 in _d_run_main
0x0043D330 in main at C:\Users\vagrant\clones\dlang.org\chmgen.d(7)
0x0048BC0D in mainCRTStartup
0x75C533CA in BaseThreadInitThunk
0x76EC9ED2 in RtlInitializeExceptionChain
0x76EC9EA5 in RtlInitializeExceptionChain

[UplinkCoder]

This is most likely because newCTFE does not have proper UTF-handling yet.

[UplinkCoder]

fixed by bailing out on string-indexing.