https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110113
--- Comment #10 from Witold Baryluk <witold.baryluk+gcc at gmail dot com> --- Thank you Iain. Amazing debugging skills. BTW. `import std;` was because dustmite reduced original import to just that. Original import was `import std.math.algebraic : sqrt;` But you already figured this out without even using Phobos.