You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
In GNU C++ mode, including Clang mode, an implicit pointer conversion that adds const below the first level without adding it at every level in between was accepted with a warning. An example is char ** to const char **. GCC and Clang reject it, and it is not const-safe.
In types.c, the fallback that accepted these conversions no longer applies in GNU C++ mode. One exception remains: when emulating GNU C++ before 8.x or Clang, the qualification conversion check doesn't look through array levels. The new helper qualification_check_skips_arrays keeps the fallback in that case, so a const-safe conversion through an array, such as double *const (*)[3] to const double *const (*)[3], is still accepted.
regressions/edg-28967 covers the rejected two- and three-level conversions, and regressions/edg-28967-positive the valid ones. regressions/edg-28967-array covers conversions through array levels with --clang, --gnu_version=70500 and --gnu_version=130300.
Five imported tests are re-recorded: Clang p6, cwg23xx, cwg3xx and qualification-conversion, and GCC conversion/qual1. Every new error is on a line the source marks as an error.
Tested with the full test suites for edg_x86_64 and edg_x86_64_cp, compared with a run of main, and with the new and changed tests for edg_x86_32 and edg_x86_32_cp.
The Changes entry uses this PR's number until there is an issue for it.
The pointer-conversion fallback using same_type_with_added_qualifiers is disabled in GNU C++ mode. Regression tests cover deep pointer qualification assignments, and a changelog entry records the change.
Changes: Pointer qualification conversion
Layer / File(s)
Summary
Conversion behavior and regression coverage src/types.c, tests/tests/regressions/edg-28967.sft.cpp, tests/tests/regressions/edg-28967-positive.sft.cpp, src/pending_changes/edg-28967-deep-pointer-qualification.txt
GNU C++ mode skips the fallback conversion using same_type_with_added_qualifiers; other modes can still use it under the existing conditions. Regression tests cover assignments that add deep const qualifications and accepted qualification assignments. The changelog describes the change.
Existing Clang-mode code using this array conversion may stop compiling. Preserve the Clang-mode behavior before merging.
Pre-merge checks: 4
Check name
Status
Explanation
Description Check
Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check
Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check
Check skipped because no linked issues were found for this pull request.
Title check
The title names the main change: rejecting unsafe multilevel pointer qualification conversions. The raw summary says GNU C++ mode now rejects deep pointer qualification conversions that add const at a…
Full details: Title check
Explanation
The title names the main change: rejecting unsafe multilevel pointer qualification conversions. The raw summary says GNU C++ mode now rejects deep pointer qualification conversions that add const at a deeper level without the required intermediate levels. The change to src/types.c disables the same_type_with_added_qualifiers fallback in GNU C++ mode, and the added tests cover the rejected and accepted cases. The objectives match this scope.
Finishing Touches
Generate unit tests (beta)
Create a new PR
Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.
Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.
71iq
added a commit
to 71iq/compiler
that referenced
this pull request
Nov 1, 2026
…8967]
In GNU C++ mode (including Clang mode), an implicit pointer conversion
that adds const below the first level without adding it at every
intermediate level (e.g., "char **" to "const char **") was accepted
with a warning. GCC and Clang reject it. Make it an error, except where
the qualification conversion check does not look through array levels
in the emulated mode (GNU C++ before 8.x and Clang), so that const-safe
conversions through arrays are still accepted.
Add regression tests, including conversions through array levels in Clang
and GNU C++ 7 modes, and update the recordings of imported tests that
now get the errors their sources expect.
71iq
changed the title
Reject unsafe deep pointer qualification conversions
Reject unsafe multilevel pointer qualification conversions [EDGcpfe/28967]
Nov 8, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
![coderabbitai[bot]](https://avatars.githubusercontent.com/in/347564?s=60&v=4){kind=small}
In GNU C++ mode, including Clang mode, an implicit pointer conversion that adds
constbelow the first level without adding it at every level in between was accepted with a warning. An example ischar **toconst char **. GCC and Clang reject it, and it is not const-safe.In
types.c, the fallback that accepted these conversions no longer applies in GNU C++ mode. One exception remains: when emulating GNU C++ before 8.x or Clang, the qualification conversion check doesn't look through array levels. The new helperqualification_check_skips_arrayskeeps the fallback in that case, so a const-safe conversion through an array, such asdouble *const (*)[3]toconst double *const (*)[3], is still accepted.regressions/edg-28967covers the rejected two- and three-level conversions, andregressions/edg-28967-positivethe valid ones.regressions/edg-28967-arraycovers conversions through array levels with--clang,--gnu_version=70500and--gnu_version=130300.Five imported tests are re-recorded: Clang
p6,cwg23xx,cwg3xxandqualification-conversion, and GCCconversion/qual1. Every new error is on a line the source marks as an error.Tested with the full test suites for edg_x86_64 and edg_x86_64_cp, compared with a run of main, and with the new and changed tests for edg_x86_32 and edg_x86_32_cp.
The
Changesentry uses this PR's number until there is an issue for it.Reported in discussion #297.