[clang-tools-extra] [clang-tidy] Fix `performance-noexcept-move-constructor` for implicit `noexcept(false)` (PR #226488)
via cfe-commits
cfe-commits at lists.llvm.org
Thu Oct 1 07:46:17 PDT 2026
https://github.com/cpp-engine updated https://github.com/llvm/llvm-project/pull/226488
>From b513dc568af3516f0f5eb70245073bfcd055b608 Mon Sep 17 00:00:00 2001
From: Agaev G <cpp.thread at gmail.com>
Date: Fri, 25 Sep 2026 13:04:11 +0000
Subject: [PATCH 1/7] [clang-tidy] Fix performance-noexcept-move-constructor
for implicit noexcept(false)
---
.../performance/NoexceptFunctionBaseCheck.cpp | 17 ++++++++-------
.../performance/noexcept-move-constructor.cpp | 21 +++++++++++++++++++
2 files changed, 31 insertions(+), 7 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/performance/NoexceptFunctionBaseCheck.cpp b/clang-tools-extra/clang-tidy/performance/NoexceptFunctionBaseCheck.cpp
index 33d80615fb19f..32d85e18dff95 100644
--- a/clang-tools-extra/clang-tidy/performance/NoexceptFunctionBaseCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/NoexceptFunctionBaseCheck.cpp
@@ -26,13 +26,16 @@ void NoexceptFunctionBaseCheck::check(const MatchFinder::MatchResult &Result) {
// Don't complain about nothrow(false), but complain on nothrow(expr)
// where expr evaluates to false.
- const auto *ProtoType = FuncDecl->getType()->castAs<FunctionProtoType>();
- const Expr *NoexceptExpr = ProtoType->getNoexceptExpr();
- if (NoexceptExpr) {
- NoexceptExpr = NoexceptExpr->IgnoreImplicit();
- if (!isa<CXXBoolLiteralExpr>(NoexceptExpr))
- reportNoexceptEvaluatedToFalse(FuncDecl, NoexceptExpr);
- return;
+ const auto ExceptionSpecSourceRange = FuncDecl->getExceptionSpecSourceRange();
+ if (ExceptionSpecSourceRange.isValid()) {
+ const auto *ProtoType = FuncDecl->getType()->castAs<FunctionProtoType>();
+ const Expr *NoexceptExpr = ProtoType->getNoexceptExpr();
+ if (NoexceptExpr) {
+ NoexceptExpr = NoexceptExpr->IgnoreImplicit();
+ if (!isa<CXXBoolLiteralExpr>(NoexceptExpr))
+ reportNoexceptEvaluatedToFalse(FuncDecl, NoexceptExpr);
+ return;
+ }
}
const auto Diag = reportMissingNoexcept(FuncDecl);
diff --git a/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp b/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
index 76e1d9e493421..42a1287163d92 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
@@ -2,6 +2,8 @@
// RUN: %check_clang_tidy -std=c++17-or-later -check-suffixes=,ERR %s performance-noexcept-move-constructor %t \
// RUN: -- --fix-errors -- -fexceptions -DENABLE_ERROR
+#include <utility>
+
namespace std
{
template <typename T>
@@ -181,6 +183,25 @@ struct O : virtual IntWrapper, ThrowOnAnything {
// CHECK-FIXES: O &operator=(O &&) noexcept = default;
};
+struct P {
+ P() = default;
+
+ P(P &&) = default;
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: move constructors should be marked noexcept [performance-noexcept-move-constructor]
+ // CHECK-FIXES: P(P &&) noexcept = default;
+ P &operator=(P &&) = default;
+ // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: move assignment operators should be marked noexcept [performance-noexcept-move-constructor]
+ // CHECK-FIXES: P &operator=(P &&) noexcept = default;
+
+ InheritFromThrowOnAnything IFF;
+};
+
+void p() {
+ P P1{};
+ P P2{std::move(P1)};
+ P P3 = std::move(P2);
+}
+
class OK {};
void f() {
>From 0a62218f1ea96122dd7e611898ed515d6df0dcfc Mon Sep 17 00:00:00 2001
From: "Agaev G." <cpp.thread at gmail.com>
Date: Sun, 27 Sep 2026 17:14:55 +0400
Subject: [PATCH 2/7] [clang-tidy] Fix test and add a release note
---
clang-tools-extra/docs/ReleaseNotes.md | 4 ++++
.../checkers/performance/noexcept-move-constructor.cpp | 2 +-
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index 0441aef375c54..535baf66b2453 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -322,6 +322,10 @@ infrastructure are described first, followed by tool-specific sections.
<clang-tidy/checks/readability/use-std-min-max>` check by fixing spurious
trailing semicolons and lost comments when the `if` body has no braces.
+- Improved {doc}`noexcept-move-constructors
+ <clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
+ false positives for implicitly declared noexcept(false).
+
#### Removed checks
- Removed the deprecated `zircon-temporary-objects` check. Users should migrate to
diff --git a/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp b/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
index 42a1287163d92..1b705aada6c2b 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
@@ -199,7 +199,7 @@ struct P {
void p() {
P P1{};
P P2{std::move(P1)};
- P P3 = std::move(P2);
+ P1 = std::move(P2);
}
class OK {};
>From 21020c0d3c2b992b44c71972bb76e64bbcae7f5e Mon Sep 17 00:00:00 2001
From: "Agaev G." <cpp.thread at gmail.com>
Date: Sun, 27 Sep 2026 19:18:25 +0400
Subject: [PATCH 3/7] [clang-tidy] Fix order of release notes
---
clang-tools-extra/docs/ReleaseNotes.md | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index f69b45d5b38de..ed0e5b8f64e8b 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -249,6 +249,10 @@ infrastructure are described first, followed by tool-specific sections.
<clang-tidy/checks/modernize/use-nullptr>` to turn `decltype(nullptr)` into
`std::nullptr_t` from `<cstdef>`.
+- Improved {doc}`noexcept-move-constructors
+ <clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
+ false positives for implicitly declared `noexcept(false)`.
+
- Improved {doc}`performance-inefficient-algorithm
<clang-tidy/checks/performance/inefficient-algorithm>` check to no longer
produce a fix with the container or the searched-for value missing, such as
@@ -333,10 +337,6 @@ infrastructure are described first, followed by tool-specific sections.
<clang-tidy/checks/readability/use-std-min-max>` check by fixing spurious
trailing semicolons and lost comments when the `if` body has no braces.
-- Improved {doc}`noexcept-move-constructors
- <clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
- false positives for implicitly declared `noexcept(false)`.
-
#### Removed checks
- Removed the deprecated `zircon-temporary-objects` check. Users should migrate to
>From 7dce1eaf6b73c7fa43547d03767ea506c57c6ef3 Mon Sep 17 00:00:00 2001
From: "Agaev G." <cpp.thread at gmail.com>
Date: Mon, 28 Sep 2026 17:40:30 +0400
Subject: [PATCH 4/7] [clang-tidy] Fix performance-noexcept-move-constructor
for implicit noexcept(false)
---
.../utils/ExceptionSpecAnalyzer.cpp | 27 ++++++++++++-------
.../performance/noexcept-move-constructor.cpp | 10 +++++++
2 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/utils/ExceptionSpecAnalyzer.cpp b/clang-tools-extra/clang-tidy/utils/ExceptionSpecAnalyzer.cpp
index 2da09669dd7f8..b02a79f37a66a 100644
--- a/clang-tools-extra/clang-tidy/utils/ExceptionSpecAnalyzer.cpp
+++ b/clang-tools-extra/clang-tidy/utils/ExceptionSpecAnalyzer.cpp
@@ -86,26 +86,33 @@ ExceptionSpecAnalyzer::analyzeRecord(const CXXRecordDecl *RecordDecl,
if (getDefaultableMemberKind(MethodDecl) == Kind)
return analyze(MethodDecl);
+ State Result = State::NotThrowing;
for (const auto &BaseSpec : RecordDecl->bases()) {
- const State Result = analyzeBase(BaseSpec, Kind);
- if (Result == State::Throwing || Result == State::Unknown)
- return Result;
+ const State CurrentState = analyzeBase(BaseSpec, Kind);
+ if (CurrentState == State::Throwing)
+ return CurrentState;
+ if (CurrentState == State::Unknown)
+ Result = CurrentState;
}
for (const auto &BaseSpec : RecordDecl->vbases()) {
- const State Result = analyzeBase(BaseSpec, Kind);
- if (Result == State::Throwing || Result == State::Unknown)
- return Result;
+ const State CurrentState = analyzeBase(BaseSpec, Kind);
+ if (CurrentState == State::Throwing)
+ return CurrentState;
+ if (CurrentState == State::Unknown)
+ Result = CurrentState;
}
for (const auto *FDecl : RecordDecl->fields())
if (!FDecl->isInvalidDecl() && !FDecl->isUnnamedBitField()) {
- const State Result = analyzeFieldDecl(FDecl, Kind);
- if (Result == State::Throwing || Result == State::Unknown)
- return Result;
+ const State CurrentState = analyzeFieldDecl(FDecl, Kind);
+ if (CurrentState == State::Throwing)
+ return CurrentState;
+ if (CurrentState == State::Unknown)
+ Result = CurrentState;
}
- return State::NotThrowing;
+ return Result;
}
ExceptionSpecAnalyzer::State
diff --git a/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp b/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
index 1b705aada6c2b..4e91c0a517cc6 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/performance/noexcept-move-constructor.cpp
@@ -2,6 +2,7 @@
// RUN: %check_clang_tidy -std=c++17-or-later -check-suffixes=,ERR %s performance-noexcept-move-constructor %t \
// RUN: -- --fix-errors -- -fexceptions -DENABLE_ERROR
+#include <string>
#include <utility>
namespace std
@@ -202,6 +203,15 @@ void p() {
P1 = std::move(P2);
}
+struct Q {
+ Q &operator=(Q &&) = default;
+ // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: move assignment operators should be marked noexcept [performance-noexcept-move-constructor]
+ // CHECK-FIXES: Q &operator=(Q &&) noexcept = default;
+
+ std::string additional_field;
+ ThrowOnAnything field;
+};
+
class OK {};
void f() {
>From 36f58a26ee025f7203e6fb1572c27de897da2277 Mon Sep 17 00:00:00 2001
From: cpp-engine <cpp.thread at gmail.com>
Date: Mon, 28 Sep 2026 20:22:33 +0400
Subject: [PATCH 5/7] [clang-tidy] Fix release note
Co-authored-by: EugeneZelenko <eugene.zelenko at gmail.com>
---
clang-tools-extra/docs/ReleaseNotes.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index ed0e5b8f64e8b..74966a10d7e3c 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -249,7 +249,7 @@ infrastructure are described first, followed by tool-specific sections.
<clang-tidy/checks/modernize/use-nullptr>` to turn `decltype(nullptr)` into
`std::nullptr_t` from `<cstdef>`.
-- Improved {doc}`noexcept-move-constructors
+- Improved {doc}`performance-noexcept-move-constructor
<clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
false positives for implicitly declared `noexcept(false)`.
>From e8c78b1f6ec813424e2efe58d72bc08e99304323 Mon Sep 17 00:00:00 2001
From: "Agaev G." <cpp.thread at gmail.com>
Date: Mon, 28 Sep 2026 20:36:19 +0400
Subject: [PATCH 6/7] [clang-tidy] Fix order of release notes
---
clang-tools-extra/docs/ReleaseNotes.md | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index 74966a10d7e3c..0deab68d01aaa 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -249,10 +249,6 @@ infrastructure are described first, followed by tool-specific sections.
<clang-tidy/checks/modernize/use-nullptr>` to turn `decltype(nullptr)` into
`std::nullptr_t` from `<cstdef>`.
-- Improved {doc}`performance-noexcept-move-constructor
- <clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
- false positives for implicitly declared `noexcept(false)`.
-
- Improved {doc}`performance-inefficient-algorithm
<clang-tidy/checks/performance/inefficient-algorithm>` check to no longer
produce a fix with the container or the searched-for value missing, such as
@@ -261,6 +257,10 @@ infrastructure are described first, followed by tool-specific sections.
offered when an argument covers only part of a macro expansion, as it then
has no source text of its own.
+- Improved {doc}`performance-noexcept-move-constructor
+ <clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
+ false positives for implicitly declared `noexcept(false)`.
+
- Improved {doc}`readability-convert-member-functions-to-static
<clang-tidy/checks/readability/convert-member-functions-to-static>` check by
fixing a crash when checking a const-qualified method declared with the
>From 07e9df671246f4f692ab7f041f4be138a02b09d4 Mon Sep 17 00:00:00 2001
From: "Agaev G." <cpp.thread at gmail.com>
Date: Thu, 1 Oct 2026 16:53:24 +0400
Subject: [PATCH 7/7] [clang-tidy] Fix release note
---
clang-tools-extra/docs/ReleaseNotes.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index 0deab68d01aaa..3e150c070f994 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -259,7 +259,7 @@ infrastructure are described first, followed by tool-specific sections.
- Improved {doc}`performance-noexcept-move-constructor
<clang-tidy/checks/performance/noexcept-move-constructor>` check by fixing
- false positives for implicitly declared `noexcept(false)`.
+ false negatives for implicitly `noexcept(false)` move operations.
- Improved {doc}`readability-convert-member-functions-to-static
<clang-tidy/checks/readability/convert-member-functions-to-static>` check by
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