Landing: de23057dd6e8

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Project / Subsystem

gcc / gccrs

Date

2026-09-08

Author

Philip Herron

Commit

de23057dd6e82889d69c7cdeaee3073fa78a9078

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: gccrs
patch_id: —
commit_hash: de23057dd6e82889d69c7cdeaee3073fa78a9078
source_type: github
headline: Where clauses handled in two passes
tldr: GCC Rust's type checking now uses two passes to correctly resolve complex where clauses and type bindings.
author: Philip Herron
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • rust
• type-checking
• generics
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/de23057dd6e82889d69c7cdeaee3073fa78a9078
date: 2026-09-08T00:00:00.000Z

GCC Rust’s type checker now uses a two-pass approach to handle ‘where’ clauses, improving the resolution of type constraints. The first pass registers bounds on single-segment TypePaths, and the second pass handles regular type bindings like I::Item or Item = U::Item. This ordering is crucial for correctly resolving dependencies where initial predicates must be established before parameter declarations and projections.