Landing: a310db3ba39d

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Project / Subsystem

gcc / c++

Date

2026-09-04

Author

Vladislav Semykin

Commit

a310db3ba39dbf8bd4db94ee5de7acce5e1cca69

Source

github

Perf win

No

Breaking

No

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All attributes

project: gcc
subsystem: c++
patch_id: —
commit_hash: a310db3ba39dbf8bd4db94ee5de7acce5e1cca69
source_type: github
headline: c++: improve lambda capture of typeid expressions
tldr: Fixes a bug where generic lambdas incorrectly skipped capturing local entities in typeid expressions.
author: Vladislav Semykin
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • c++
• lambda
• typeid
• compiler-error
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/a310db3ba39dbf8bd4db94ee5de7acce5e1cca69
date: 2026-09-04T00:00:00.000Z

A bug in C++ lambda capture has been fixed, resolving an ICE that occurred when generic lambdas interacted with typeid expressions. Previously, the compiler could incorrectly skip capturing local entities required by the C++ standard when evaluating typeid. This change modifies how the compiler determines if a typeid expression necessitates a capture, ensuring correct behavior even within template contexts and for complex nested typeid expressions. A new mechanism, cp_unevaluated_typeid_cutoff, is introduced to manage this evaluation process.