Landing: 9d868e49122b

Project / Subsystem

gcc / gcc/fortran

Date

2026-06-09

Author

Thomas Koenig

Commit

9d868e49122b4ce45cffa4d3f47f6ef371e80a24

Source

github

Perf win

No

Breaking

No

All attributes

project
gcc
subsystem
gcc/fortran
patch_id
commit_hash
9d868e49122b4ce45cffa4d3f47f6ef371e80a24
source_type
github
headline
GCC implements new Fortran warnings for unused and undefined variables.
tldr
GCC now provides new warnings for Fortran code concerning undefined variables and variables set but never used, improving code quality and catching potential e…
author
Thomas Koenig
outcome
committed
performance_win
false
breaking_change
false
series_id
series_parts
[]
tags
  • fortran
  • warnings
  • static-analysis
  • code-quality
discussion_id_link
github:gcc-mirror/gcc#30438
bugzilla_pr
date
2026-06-09T00:00:00.000Z

This commit introduces new -Wundefined-vars and -Wunused-but-set-variable warnings for Fortran, addressing issues where variables are used without prior definition or set to a value that is never subsequently read. The implementation tracks variable usage and definition within a namespace, carefully avoiding false positives by excluding certain conditions. This significantly enhances compiler diagnostics for Fortran developers, helping them identify and correct potential logical flaws and dead code, ultimately leading to more robust and maintainable programs.