Hi, I try to compile darktable directly from the sources (no emerge) with Gcc version 5.4.0 (Gentoo 5.4.0-r3 p1.3, pie-0.6.5). There seem to have a bug according to the developper of Darktable. I am not really sure the bug in GCC is of interest since the bug is on a non Gentoo package: darktable extract with git. Here is a cut-and-paste from the bug report "gcc 5 fails at valid lambda code" from Linux Mint. Note: I have the same bug with the Gentoo-GCC compiler. Hello The bug was found at an attempt of compilation of the mater branch of darktable from git. Roman Lebedev, the author of the code, asked to file a bug in OS bugtracker. Linux Mint 18.2 Mate x64. gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609 Here is the duplicate of the bug, filled by him in debian bugtracker https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=871250 Package: g++-5 Version: 5.4.1-11 Severity: normal Tags: upstream The test-case is creduced. Only the GCC5 fails, gcc-4.9, 6 and 7 do not. clang-3.9, 4, 5, trunk is also fine with that code. $ g++-7 -std=c++14 -c main.cpp $ g++-6 -std=c++14 -c main.cpp $ g++-5 -std=c++14 -c main.cpp main.cpp: In instantiation of ‘d::n() const::<lambda(auto:1, d::h, d::h, int, d::n() const::p, d::n() const::p)> [with auto:1 = d::n() const::<lambda()>]’: main.cpp:26:28: required from here main.cpp:23:11: error: ‘e’ is not captured if (e < e) ^ main.cpp:23:11: note: ‘const int& e’ declared here - -- System Information: Debian Release: buster/sid APT prefers unstable APT policy: (990, 'unstable'), (500, 'unstable-debug'), (1, 'experimental-debug'), (1, 'experimental') Architecture: amd64 (x86_64) Kernel: Linux 4.11.0-2-amd64 (SMP w/8 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages g++-5 depends on: ii gcc-5 5.4.1-11 ii gcc-5-base 5.4.1-11 ii libc6 2.24-14 ii libgmp10 2:6.1.2+dfsg-1 ii libisl15 0.18-1 ii libmpc3 1.0.3-1+b2 ii libmpfr4 3.1.5-1 ii libstdc++-5-dev 5.4.1-11 ii zlib1g 1:1.2.8.dfsg-5 g++-5 recommends no packages. Versions of packages g++-5 suggests: pn g++-5-multilib <none> pn gcc-5-doc <none> pn libstdc++6-5-dbg <none> - -- no debconf information *** /home/lebedevri/CREDUCE/main.cpp using a = int; using c = int; struct d { struct { a e; } f; enum h { i, j }; struct k { int l[0][0]; }; int m(k *, c *, a, int, int *) const; void n() const; }; void d::n() const { c *o; k *info; struct p { } g; p b; int errcnt; const int e = f.e; auto pass = [&](auto, h, h, int, p, p) { if (e < e) errcnt = m(0, o, 0, 0, info->l[0]); }; pass([] {}, i, j, 0, g, b); }