Testing in 2.064 git-head:

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import std.string;

string getEnum(size_t count)
{
    string en;
    en ~= "enum KeyCode\n {    \n";

    foreach (i; 0 .. count)
    {
        en ~= format("    memb_%s = %s,\n", i+1, i+1);
    }

    en ~= "} ";
    return en;
}

// Linker warning: Warning 161: Unknown CV version, ignored
// mixin(getEnum(1024));

// ICE  
// mixin(getEnum(1087));

void main() { }
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Uncomment the first mixin to start getting linker warnings. Uncomment the second one instead and an ICE is emitted:

Internal error: backend\cgcv.c 203

I ran into this while translating keycodes from another GUI library. It has just over 1100 keycodes, and I wanted to put them all in one KeyCode enum.

I can also recreate this with structs and classes, so it's not specific to enums (e.g. a struct with 1087 'static' fields). The workaround is to make the keycodes all manifest constants, e.g.:

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enum memb_1 = 1;
enum memb_2 = 2;
enum memb_3 = 3;
...
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However this does lose me the ability to give the keycodes a single type to group them under.