[clang] [LifetimeSafety] Don't enable lifetime suggestions via -Weverything (PR #232300)
Balázs Benics via cfe-commits
cfe-commits at lists.llvm.org
Thu Oct 15 05:35:34 PDT 2026
https://github.com/steakhal created https://github.com/llvm/llvm-project/pull/232300
Users sometimes enable -Weverything and get flooded by the results of the -Wlifetime-safety-suggestions diagnostics. Require these suggestions to be requested explicitly instead, e.g. via -Wlifetime-safety-suggestions or one of its subgroups.
I'm not happy with what I recommend here because it's not a real solution - rather just a bandaid for users who enable -Weverything (sometimes with -Werror).
---
Under -Weverything, a suggestion is only emitted if the user set a mapping for it explicitly. This is checked both when deciding whether to compute the suggestions at all, and at each emission site, so that enabling one subgroup does not let -Weverything enable the other suggestion groups.
Limitation:
The explicit-mapping check inspects the current diagnostic state via `DiagnosticsEngine::getDiagnosticMappings()`, not the state at the diagnostic's location. So a suggestion group enabled only within a `#pragma clang diagnostic push`/`pop` region may still be suppressed under -Weverything, especially with the TU-level analysis which runs at the end of the translation unit. Command-line flags work as expected.
Authored-By: claude
>From f97a9d6f068cd0378d9490c311d9eed346f4ab8e Mon Sep 17 00:00:00 2001
From: Balazs Benics <benicsbalazs at gmail.com>
Date: Thu, 15 Oct 2026 13:10:41 +0100
Subject: [PATCH] [LifetimeSafety] Don't enable lifetime suggestions via
-Weverything
Users sometimes enable -Weverything and get flooded by the results of the
-Wlifetime-safety-suggestions diagnostics. Require these suggestions to be
requested explicitly instead, e.g. via -Wlifetime-safety-suggestions or one
of its subgroups.
I'm not happy with what I recommend here because it's not a real solution -
rather just a bandaid for users who enable -Weverything (sometimes with -Werror).
---
Under -Weverything, a suggestion is only emitted if the user set a mapping
for it explicitly. This is checked both when deciding whether to compute
the suggestions at all, and at each emission site, so that enabling one
subgroup does not let -Weverything enable the other suggestion groups.
Limitation:
The explicit-mapping check inspects the current diagnostic state via
`DiagnosticsEngine::getDiagnosticMappings()`, not the state at the
diagnostic's location. So a suggestion group enabled only within a
`#pragma clang diagnostic push`/`pop` region may still be suppressed
under -Weverything, especially with the TU-level analysis which runs at
the end of the translation unit. Command-line flags work as expected.
Authored-By: claude
---
clang/docs/ReleaseNotes.md | 5 ++
clang/lib/Sema/SemaLifetimeSafety.h | 25 ++++++++-
.../annotation-suggestions-weverything.cpp | 56 +++++++++++++++++++
3 files changed, 85 insertions(+), 1 deletion(-)
create mode 100644 clang/test/Sema/LifetimeSafety/annotation-suggestions-weverything.cpp
diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md
index b6658dc7d81afb..f49c82319c5d09 100644
--- a/clang/docs/ReleaseNotes.md
+++ b/clang/docs/ReleaseNotes.md
@@ -510,6 +510,11 @@ features cannot lower the translation-unit ABI level;
- Lifetime safety analysis is now enabled for C by default. The `-fexperimental-lifetime-safety-c`
flag is renamed to `-flifetime-safety-c`. Use `-fno-lifetime-safety-c` to disable it.
+- The lifetime annotation suggestions (`-Wlifetime-safety-suggestions` and its
+ subgroups) are no longer enabled by `-Weverything`. Users sometimes enable
+ `-Weverything` and would get flooded by the results of these suggestions. They
+ now have to be requested explicitly, e.g. via `-Wlifetime-safety-suggestions`.
+
- Improved `-Wassign-enum` performance by caching enum enumerator values. (#GH176454)
- Fixed a false negative in `-Warray-bounds` where the warning was suppressed
diff --git a/clang/lib/Sema/SemaLifetimeSafety.h b/clang/lib/Sema/SemaLifetimeSafety.h
index 3db298b6fec85c..dd083d5860a21f 100644
--- a/clang/lib/Sema/SemaLifetimeSafety.h
+++ b/clang/lib/Sema/SemaLifetimeSafety.h
@@ -77,6 +77,25 @@ inline bool ShouldCheckFieldOriginEscape(Sema &S, const Decl *D) {
diag::warn_lifetime_safety_field_origin_escape, D->getBeginLoc());
}
+/// Returns true if the annotation suggestion \p DiagID should be emitted at
+/// \p Loc.
+/// Unlike other warnings, the suggestions are not enabled by -Weverything
+/// alone; they have to be requested explicitly.
+/// Users sometimes enable -Weverything and would otherwise get flooded by the
+/// results of the lifetime-safety suggestions.
+/// FIXME: Ideally this should be handled in a more generic way.
+inline bool isSuggestionEnabled(DiagnosticsEngine &Diags, unsigned DiagID,
+ SourceLocation Loc) {
+ if (Diags.isIgnored(DiagID, Loc))
+ return false;
+ if (!Diags.getEnableAllWarnings())
+ return true;
+ for (const auto &[ID, Mapping] : Diags.getDiagnosticMappings())
+ if (ID == DiagID)
+ return Mapping.isUser();
+ return false;
+}
+
inline bool ShouldSuggestLifetimeAnnotations(Sema &S, const Decl *D) {
DiagnosticsEngine &Diags = S.getDiagnostics();
constexpr unsigned DiagIDs[] = {
@@ -87,7 +106,7 @@ inline bool ShouldSuggestLifetimeAnnotations(Sema &S, const Decl *D) {
diag::warn_lifetime_safety_intra_tu_this_suggestion,
diag::warn_lifetime_safety_cross_tu_this_suggestion};
for (unsigned DiagID : DiagIDs)
- if (!Diags.isIgnored(DiagID, D->getBeginLoc()))
+ if (isSuggestionEnabled(Diags, DiagID, D->getBeginLoc()))
return true;
return false;
}
@@ -349,6 +368,8 @@ class LifetimeSafetySemaHelperImpl : public LifetimeSafetySemaHelper {
: diag::warn_lifetime_safety_intra_tu_param_suggestion;
auto [InsertionPoint, FixItText] = getLifetimeBoundFixIt(ParmToAnnotate);
+ if (!isSuggestionEnabled(S.getDiagnostics(), DiagID, InsertionPoint))
+ return;
S.Diag(InsertionPoint, DiagID)
<< ParmToAnnotate->getSourceRange()
@@ -455,6 +476,8 @@ class LifetimeSafetySemaHelperImpl : public LifetimeSafetySemaHelper {
: diag::warn_lifetime_safety_intra_tu_this_suggestion;
auto [InsertionPoint, FixItText] = getLifetimeBoundFixIt(MD);
+ if (!isSuggestionEnabled(S.getDiagnostics(), DiagID, InsertionPoint))
+ return;
S.Diag(InsertionPoint, DiagID)
<< MD->getNameInfo().getSourceRange()
diff --git a/clang/test/Sema/LifetimeSafety/annotation-suggestions-weverything.cpp b/clang/test/Sema/LifetimeSafety/annotation-suggestions-weverything.cpp
new file mode 100644
index 00000000000000..6d3a4abf3a7df8
--- /dev/null
+++ b/clang/test/Sema/LifetimeSafety/annotation-suggestions-weverything.cpp
@@ -0,0 +1,56 @@
+// The lifetime annotation suggestions are not enabled by -Weverything alone.
+//
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -flifetime-safety-inference \
+// RUN: -fexperimental-lifetime-safety-tu-analysis -Weverything %s 2>&1 | \
+// RUN: FileCheck %s --check-prefix=NONE --implicit-check-not="should be marked"
+//
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -flifetime-safety-inference \
+// RUN: -fexperimental-lifetime-safety-tu-analysis -Weverything \
+// RUN: -Wlifetime-safety-suggestions %s 2>&1 | \
+// RUN: FileCheck %s --check-prefixes=PARAM,CTOR \
+// RUN: --implicit-check-not="should be marked"
+//
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -flifetime-safety-inference \
+// RUN: -fexperimental-lifetime-safety-tu-analysis \
+// RUN: -Wlifetime-safety-suggestions -Weverything %s 2>&1 | \
+// RUN: FileCheck %s --check-prefixes=PARAM,CTOR \
+// RUN: --implicit-check-not="should be marked"
+//
+// Enabling only a subgroup must not let -Weverything enable the rest.
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -flifetime-safety-inference \
+// RUN: -fexperimental-lifetime-safety-tu-analysis -Weverything \
+// RUN: -Wlifetime-safety-intra-tu-constructor-suggestions %s 2>&1 | \
+// RUN: FileCheck %s --check-prefix=CTOR --implicit-check-not="should be marked"
+//
+// RUN: not %clang_cc1 -fsyntax-only -std=c++17 -flifetime-safety-inference \
+// RUN: -fexperimental-lifetime-safety-tu-analysis -Weverything \
+// RUN: -Werror=lifetime-safety-intra-tu-suggestions %s 2>&1 | \
+// RUN: FileCheck %s --check-prefix=ERROR --implicit-check-not="should be marked"
+
+// NONE-NOT: should be marked
+
+struct View;
+
+struct [[gsl::Owner]] MyObj {
+ int id;
+ MyObj();
+ ~MyObj();
+};
+
+struct [[gsl::Pointer()]] View {
+ View(const MyObj &);
+ View();
+};
+
+View return_view(View a) {
+ // PARAM: :[[@LINE-1]]:24: warning: parameter in intra-TU function should be marked {{\[\[}}clang::lifetimebound]] [-Wlifetime-safety-intra-tu-suggestions]
+ // ERROR: :[[@LINE-2]]:24: error: parameter in intra-TU function should be marked {{\[\[}}clang::lifetimebound]] [-Werror,-Wlifetime-safety-intra-tu-suggestions]
+ return a;
+}
+
+struct CaptureRefToView {
+ View v;
+ CaptureRefToView(const MyObj &obj) : v(obj) {}
+ // CTOR: :[[@LINE-1]]:36: warning: parameter in intra-TU constructor should be marked {{\[\[}}clang::lifetimebound]] [-Wlifetime-safety-intra-tu-constructor-suggestions]
+ // ERROR: :[[@LINE-2]]:36: error: parameter in intra-TU constructor should be marked {{\[\[}}clang::lifetimebound]] [-Werror,-Wlifetime-safety-intra-tu-constructor-suggestions]
+};
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