https://github.com/Maetveis updated
https://github.com/llvm/llvm-project/pull/116965
From 0dd94643cd32992e4b54463eea8a73d377b9169e Mon Sep 17 00:00:00 2001
From: Gergely Meszaros <gergely.mesza...@intel.com>
Date: Wed, 20 Nov 2024 12:55:59 +0000
Subject: [PATCH 1/2] [Clang] Only ignore special methods for unused private
fields in BuildFieldReferenceExpr
The original code assumed that only special methods might be defined
as defaulted. Since C++20 comparison operators might be defaulted too,
and we *do* want to consider those as using the fields of the class.
Fixes: #116961
---
clang/lib/Sema/SemaExprMember.cpp | 12 ++++++++++--
clang/test/SemaCXX/warn-unused-private-field.cpp | 14 ++++++++++++++
2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Sema/SemaExprMember.cpp
b/clang/lib/Sema/SemaExprMember.cpp
index c32df607692813..46821dc8746b2a 100644
--- a/clang/lib/Sema/SemaExprMember.cpp
+++ b/clang/lib/Sema/SemaExprMember.cpp
@@ -1874,8 +1874,16 @@ Sema::BuildFieldReferenceExpr(Expr *BaseExpr, bool
IsArrow,
Context.getAttributedType(attr::NoDeref, MemberType, MemberType);
}
- auto *CurMethod = dyn_cast<CXXMethodDecl>(CurContext);
- if (!(CurMethod && CurMethod->isDefaulted()))
+ auto isDefaultedSpecialMember = [this](const DeclContext *Ctx) {
+ auto *Method = dyn_cast<CXXMethodDecl>(CurContext);
+ if (!Method || !Method->isDefaulted())
+ return false;
+
+ return getDefaultedFunctionKind(Method).isSpecialMember();
+ };
+
+ // Implicit special members should not mark fields as used.
+ if (!isDefaultedSpecialMember(CurContext))
UnusedPrivateFields.remove(Field);
ExprResult Base = PerformObjectMemberConversion(BaseExpr, SS.getScopeRep(),
diff --git a/clang/test/SemaCXX/warn-unused-private-field.cpp
b/clang/test/SemaCXX/warn-unused-private-field.cpp
index 1128eacc309d9f..9913dbaafb7a57 100644
--- a/clang/test/SemaCXX/warn-unused-private-field.cpp
+++ b/clang/test/SemaCXX/warn-unused-private-field.cpp
@@ -20,6 +20,20 @@ class SpaceShipDefaultCompare {
int operator<=>(const SpaceShipDefaultCompare &) const = default;
};
+class EqDefaultCompareOutOfClass {
+ int used;
+ bool operator==(const EqDefaultCompareOutOfClass &) const;
+};
+
+bool EqDefaultCompareOutOfClass::operator==(const EqDefaultCompareOutOfClass
&) const = default;
+
+class FriendEqDefaultCompareOutOfClass {
+ int used;
+ friend bool operator==(const FriendEqDefaultCompareOutOfClass &, const
FriendEqDefaultCompareOutOfClass &);
+};
+
+bool operator==(const FriendEqDefaultCompareOutOfClass &, const
FriendEqDefaultCompareOutOfClass &) = default;
+
#endif
class NotFullyDefined {
From af60ae1f09ecd199a9eea99b61595293efe5599f Mon Sep 17 00:00:00 2001
From: Gergely <gergely.mesza...@intel.com>
Date: Mon, 25 Nov 2024 17:35:03 +0000
Subject: [PATCH 2/2] Add Release Notes and comments to test
---
clang/docs/ReleaseNotes.rst | 2 ++
clang/test/SemaCXX/warn-unused-private-field.cpp | 4 ++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index fcbb3a9e6c6f81..17220e7f41b72b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -559,6 +559,8 @@ Improvements to Clang's diagnostics
- Clang now diagnoses ``= delete("reason")`` extension warnings only in
pedantic mode rather than on by default. (#GH109311).
+- Fixed a false negative ``-Wunused-private-field`` diagnostic when a
defaulted comparison operator is defined out of class (#GH116961).
+
Improvements to Clang's time-trace
----------------------------------
diff --git a/clang/test/SemaCXX/warn-unused-private-field.cpp
b/clang/test/SemaCXX/warn-unused-private-field.cpp
index 9913dbaafb7a57..047204e68617a1 100644
--- a/clang/test/SemaCXX/warn-unused-private-field.cpp
+++ b/clang/test/SemaCXX/warn-unused-private-field.cpp
@@ -21,14 +21,14 @@ class SpaceShipDefaultCompare {
};
class EqDefaultCompareOutOfClass {
- int used;
+ int used; // no warning
bool operator==(const EqDefaultCompareOutOfClass &) const;
};
bool EqDefaultCompareOutOfClass::operator==(const EqDefaultCompareOutOfClass
&) const = default;
class FriendEqDefaultCompareOutOfClass {
- int used;
+ int used; // no warning
friend bool operator==(const FriendEqDefaultCompareOutOfClass &, const
FriendEqDefaultCompareOutOfClass &);
};
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