Landing: 40cbcd4eedce

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Project / Subsystem

gcc / c++

Date

2026-08-29

Author

Vincenzo Calabretta

Commit

40cbcd4eedce587c089492213711f4b85ac35843

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: c++
patch_id: —
commit_hash: 40cbcd4eedce587c089492213711f4b85ac35843
source_type: github
headline: C++: Unshare RANGE_EXPR indices in constructors to fix mutation issues
tldr: Fixes a bug where modifying array element initializers corrupted shared constructor trees.
author: Vincenzo Calabretta
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • c++
• compiler bug
• initialization
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/40cbcd4eedce587c089492213711f4b85ac35843
date: 2026-08-29T00:00:00.000Z

A bug in C++‘s constructor handling, specifically when unsharing CONSTRUCTOR trees for array elements, has been resolved. The issue stemmed from RANGE_EXPR indices remaining shared after a shallow copy. This commit ensures that RANGE_EXPR indices are also copied, preventing modifications in one constructor from affecting others and thus avoiding incorrect initialization omissions.