Boost 1.91: warning C4702: unreachable code

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#147 opened on Apr 27, 2026 1 comment 1 reaction 0 assignees View on GitHub

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Assessment

Difficulty: 2/5
Estimated time: 1-3 hours
Newbie friendliness: 65/100

Issue type: Bug
Clarity: Mostly clear
Activity status: Quiet
Tech stack: cpp
Domain: compilers

Research direction

Start at boost/optional/detail/union_optional.hpp around line 600 and reproduce the Boost 1.91 Windows build with warnings treated as errors. Investigate the reported C4702 unreachable code and verify that the build completes without C4702/C2220.

Written by the indexing model from the issue text.

Description

Building boost 1.91 on Windows fails with

E:\jenkins\workspace\gerrit_windows_wsl\workdir\UnpackedTarball\boost\boost\optional\detail\union_optional.hpp(600) : error C2220: the following warning is treated as an error
E:\jenkins\workspace\gerrit_windows_wsl\workdir\UnpackedTarball\boost\boost\optional\detail\union_optional.hpp(600) : warning C4702: unreachable code

Dominant language: C++
Stars: 60
Forks: 75
PR merge metrics: No merged PRs in 30d

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