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import std;
import std.conv : text;
void main()
{
char[6] s;
s = "abcdef";
writeln(s, s.length); // abc6, ok it's the static array's length
string t = text("head-", s[].until('\0').array, "-tail");
writeln(t, t.length); // head-abc-tail16, why 16 instead of 13, t's type is string here
assert(t[12] == 't');
assert(t == "head-abcdef-tail");
}