[Issue 18026] Stack overflow in ddmd/dtemplate.d:6241, TemplateInstance::needsCodegen()

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18026

--- Comment #14 from ag0aep6g <ag0aep6g at gmail.com> ---
Removed Phobos from the test case from comment 10, and made sure that it fails
reliably (for me) by raising the number of enum members again:

----
enum Type
{
    x000,x001,x002,x003,x004,x005,x006,x007,x008,x009,x010,x011,x012,x013,x014,
    x015,x016,x017,x018,x019,x020,x021,x022,x023,x024,x025,x026,x027,x028,x029,
    x030,x031,x032,x033,x034,x035,x036,x037,x038,x039,x040,x041,x042,x043,x044,
    x045,x046,x047,x048,x049,x050,x051,x052,x053,x054,x055,x056,x057,x058,x059,
    x060,x061,x062,x063,x064,x065,x066,x067,x068,x069,x070,x071,x072,x073,x074,
    x075,x076,x077,x078,x079,x080,x081,x082,x083,x084,x085,x086,x087,x088,x089,
    x090,x091,x092,x093,x094,x095,x096,x097,x098,x099,x100,x101,x102,x103,x104,
    x105,x106,x107,x108,x109,x110,x111,x112,x113,x114,x115,x116,x117,x118,x119,
    x120,x121,x122,x123,x124,x125,x126,x127,x128,x129,x130,x131,x132,x133,x134,
    x135,x136,x137,x138,x139,x140,x141,x142,x143,x144,x145,x146,x147,x148,x149,
    x150,x151,x152,x153,x154,x155,x156,x157,x158,x159,x160,x161,x162,x163,x164,
    x165,x166,x167,x168,x169,x170,x171,x172,x173,x174,x175,x176,x177,x178,x179,
    x180,x181,x182,x183,x184,x185,x186,x187,x188,x189,x190,x191,x192,x193,x194,
    x195,x196,x197,x198,x199,x200,x201,x202,x203,x204,x205,x206,x207,x208,x209,
    x210,x211,x212,x213,x214,x215,x216,x217,x218,x219,x220,x221,x222,x223,x224,
    x225,x226,x227,x228,x229,x230,x231,x232,x233,x234,x235,x236,x237,x238,x239,
    x240,x241,x242,x243,x244,x245,x246,x247,x248,x249,x250,x251,x252,x253,x254,
    x255,x256,x257,x258,x259,x260,x261,x262,x263,x264,x265,x266,x267,x268,x269,
    x270,x271,x272,x273,x274,x275,x276,x277,x278,x279,x280,x281,x282,x283,x284,
    x285,x286,x287,x288,x289,x290,x291,x292,x293,x294,x295,x296,x297,x298,x299,
    x300,x301,x302,x303,x304,x305,x306,x307,x308,x309,x310,x311,x312,x313,x314,
    x315,x316,x317,x318,x319,x320,x321,x322,x323,x324,x325,x326,x327,x328,x329,
    x330,x331,x332,x333,x334,x335,x336,x337,x338,x339,x340,x341,x342,x343,x344,
    x345,x346,x347,x348,x349,x350,x351,x352,x353,x354,x355,x356,x357,x358,x359,
    x360,x361,x362,x363,x364,x365,x366,x367,x368,x369,x370,x371,x372,x373,x374,
    x375,x376,x377,x378,x379,x380,x381,x382,x383,x384,x385,x386,x387,x388,x389,
    x390,x391,x392,x393,x394,x395,x396,x397,x398,x399,x400,x401,x402,x403,x404,
    x405,x406,x407,x408,x409,x410,x411,x412,x413,x414,x415,x416,x417,x418,x419,
    x420,x421,x422,x423,x424,x425,x426,x427,x428,x429,x430,x431,x432,x433,x434,
    x435,x436,x437,x438,x439,x440,x441,x442,x443,x444,x445,x446,x447,x448,x449,
    x450,x451,x452,x453,x454,x455,x456,x457,x458,x459,x460,x461,x462,x463,x464,
    x465,x466,x467,x468,x469,x470,x471,x472,x473,x474,x475,x476,x477,x478,x479,
    x480,x481,x482,x483,x484,x485,x486,x487,x488,x489,x490,x491,x492,x493,x494,
    x495,x496,x497,x498,x499,x500,x501,x502,x503,x504,x505,x506,x507,x508,x509,
    x510,x511,x512,x513,x514,x515,x516,x517,x518,x519,x520,x521,x522,x523,x524,
    x525,x526,x527,x528,x529,x530,x531,x532,x533,x534,x535,x536,x537,x538,x539,
    x540,x541,x542,x543,x544,x545,x546,x547,x548,x549,x550,x551,x552,x553,x554,
    x555,x556,x557,x558,x559,x560,x561,x562,x563,x564,x565,x566,x567,x568,x569,
    x570,x571,x572,x573,x574,x575,x576,x577,x578,x579,x580,x581,x582,x583,x584,
    x585,x586,x587,x588,x589,x590,x591,x592,x593,x594,x595,x596,x597,x598,x599,
    x600,x601,x602,x603,x604,x605,x606,x607,x608,x609,x610,x611,x612,x613,x614,
    x615,x616,x617,x618,x619,x620,x621,x622,x623,x624,x625,x626,x627,x628,x629,
    x630,x631,x632,x633,x634,x635,x636,x637,x638,x639,x640,x641,x642,x643,x644,
    x645,x646,x647,x648,x649,x650,x651,x652,x653,x654,x655,x656,x657,x658,x659,
    x660,x661,x662,x663,x664,x665,x666,x667,x668,x669,x670,x671,x672,x673,x674,
    x675,x676,x677,x678,x679,x680,x681,x682,x683,x684,x685,x686,x687,x688,x689,
    x690,x691,x692,x693,x694,x695,x696,x697,x698,x699,x700,x701,x702,x703,x704,
    x705,x706,x707,x708,x709,x710,x711,x712,x713,x714,x715,x716,x717,x718,x719,
    x720,x721,x722,x723,x724,x725,x726,x727,x728,x729,x730,x731,x732,x733,x734,
    x735,x736,x737,x738,x739,x740,x741,x742,x743,x744,x745,x746,x747,x748,x749,
    x750,x751,x752,x753,x754,x755,x756,x757,x758,x759,x760,x761,x762,x763,x764,
    x765,x766,x767,x768,x769,x770,x771,x772,x773,x774,x775,x776,x777,x778,x779,
    x780,x781,x782,x783,x784,x785,x786,x787,x788,x789,x790,x791,x792,x793,x794,
    x795,x796,x797,x798,x799,x800,x801,x802,x803,x804,x805,x806,x807,x808,x809,
}

template Unqual() {}
struct FormatSpec() if (is(Unqual!()) || !is(Unqual!())) {}

void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (is(T == string)) {}

void formatValueImpl(W, T)(W w, T val, FormatSpec!() f)
if (is(T == Type))
{
    foreach (i, e; __traits(allMembers, T))
    {
        formatValueImpl!(W, string)(w, e, f);
    }
}

void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T val, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}
void formatValueImpl(W, T)(W w, T obj, FormatSpec!() f) if (false) {}

alias fvi_Type_1 = formatValueImpl!(void function(char c), Type);
alias fvi_Type_2 = formatValueImpl!(void function(const(char)[] s), Type);
alias fvi_Type_3 = formatValueImpl!(void delegate(char c), Type);
alias fvi_Type_4 = formatValueImpl!(void delegate(const char[]), Type);
alias fvi_Type_5 = formatValueImpl!(void delegate(const(char)[] s), Type);
----

If this happens to not crash on other systems, adding more enum members and/or
"false" formatValueImpl overloads and/or fvi_Type_* variants might do the
trick.

--