Missing `@nogc` check for enum variable initialization

[dkorpel]

This @nogc function compiles, but allocates an array literal with the GC at runtime:

void f() @nogc
{
    enum DA : int[] { a = [1,2,3] }
    DA da;
}

[dkorpel]

Related case:

void f() @nogc
{
    int i = *cast(int*)cast(char[4])['0', '0', '0', '0'];
}