Landing: e4f550457b0b

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Project / Subsystem

gcc / libstdc++

Date

2026-09-17

Author

Patrick Palka

Commit

e4f550457b0b5c9c87356f6dfc60ae980e319585

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: libstdc++
patch_id: —
commit_hash: e4f550457b0b5c9c87356f6dfc60ae980e319585
source_type: github
headline: libstdc++: Fix SFINAE with shared_ptr and invalid deleter
tldr: Ensures correct SFINAE behavior for shared_ptr constructors that accept deleters, aligning with C++20 constraints.
author: Patrick Palka
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • libstdc++
• smart pointers
• SFINAE
• C++20
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/e4f550457b0b5c9c87356f6dfc60ae980e319585
date: 2026-09-17T00:00:00.000Z

This change fixes SFINAE (Substitution Failure Is Not An Error) issues in libstdc++ concerning shared_ptr constructors that take a deleter. It implements the C++20 constraints for these constructors and proactively adopts a proposed resolution for LWG 4110, which relaxes constraints on nullptr_t overloads. New tests have been added to verify the corrected behavior.