https://github.com/whiteio updated
https://github.com/llvm/llvm-project/pull/116871
>From 29330456191334afb6cd82ae44f496c522985877 Mon Sep 17 00:00:00 2001
From: Chris White <chriswhiteio...@gmail.com>
Date: Tue, 19 Nov 2024 20:06:28 +0000
Subject: [PATCH 1/3] [Clang] Fix -Wunused-private-field false negative with
defaulted comparison operators
Fix -Wunused-private-field suppressing warnings when defaulted comparison
operators are declared as friend functions. The warning should only be
suppressed for comparison operators that are class members.
Fixes #116270
---
clang/lib/Sema/SemaDeclCXX.cpp | 2 +-
clang/test/SemaCXX/warn-unused-private-field.cpp | 11 +++++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 7e8e321c4b90e6..7434a29191cdb5 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -7535,7 +7535,7 @@ void Sema::CheckExplicitlyDefaultedFunction(Scope *S,
FunctionDecl *FD) {
return;
}
- if (DefKind.isComparison())
+ if (DefKind.isComparison() && isa<CXXRecordDecl>(FD->getDeclContext()))
UnusedPrivateFields.clear();
if (DefKind.isSpecialMember()
diff --git a/clang/test/SemaCXX/warn-unused-private-field.cpp
b/clang/test/SemaCXX/warn-unused-private-field.cpp
index bf104b1a76a656..4448d4715faad0 100644
--- a/clang/test/SemaCXX/warn-unused-private-field.cpp
+++ b/clang/test/SemaCXX/warn-unused-private-field.cpp
@@ -40,6 +40,17 @@ class FriendEqDefaultCompareOutOfClass {
bool operator==(const FriendEqDefaultCompareOutOfClass &, const
FriendEqDefaultCompareOutOfClass &) = default;
+class UnusedConstPrivateField {
+ public:
+ UnusedConstPrivateField() : unused_(0) {}
+ private:
+ const int unused_; // expected-warning{{private field 'unused_' is not used}}
+};
+
+class FriendEqDefaultCompare {
+ friend auto operator==(FriendEqDefaultCompare, FriendEqDefaultCompare) ->
bool = default;
+};
+
#endif
class NotFullyDefined {
>From a7885a848d7a439659af33d69a13b245c725c690 Mon Sep 17 00:00:00 2001
From: Chris White <chriswhiteio...@gmail.com>
Date: Wed, 20 Nov 2024 18:34:52 +0000
Subject: [PATCH 2/3] Address review comments
---
clang/lib/Sema/SemaDeclCXX.cpp | 11 +++++++++--
.../test/SemaCXX/warn-unused-private-field.cpp | 18 ++++++++++++++----
2 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 7434a29191cdb5..f7a0b3c059ec91 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -7535,8 +7535,15 @@ void Sema::CheckExplicitlyDefaultedFunction(Scope *S,
FunctionDecl *FD) {
return;
}
- if (DefKind.isComparison() && isa<CXXRecordDecl>(FD->getDeclContext()))
- UnusedPrivateFields.clear();
+ if (DefKind.isComparison()) {
+ auto PT = FD->getParamDecl(0)->getType();
+ if (const CXXRecordDecl *RD =
+ PT.getNonReferenceType()->getAsCXXRecordDecl()) {
+ for (FieldDecl *Field : RD->fields()) {
+ UnusedPrivateFields.remove(Field);
+ }
+ }
+ }
if (DefKind.isSpecialMember()
? CheckExplicitlyDefaultedSpecialMember(cast<CXXMethodDecl>(FD),
diff --git a/clang/test/SemaCXX/warn-unused-private-field.cpp
b/clang/test/SemaCXX/warn-unused-private-field.cpp
index 4448d4715faad0..9eccfc20430439 100644
--- a/clang/test/SemaCXX/warn-unused-private-field.cpp
+++ b/clang/test/SemaCXX/warn-unused-private-field.cpp
@@ -41,16 +41,26 @@ class FriendEqDefaultCompareOutOfClass {
bool operator==(const FriendEqDefaultCompareOutOfClass &, const
FriendEqDefaultCompareOutOfClass &) = default;
class UnusedConstPrivateField {
- public:
- UnusedConstPrivateField() : unused_(0) {}
- private:
- const int unused_; // expected-warning{{private field 'unused_' is not used}}
+public:
+ UnusedConstPrivateField() : unused_(0) {}
+private:
+ const int unused_; // expected-warning{{private field 'unused_' is not
used}}
+};
+
+class HasUnusedField {
+ int unused_; // expected-warning{{private field 'unused_' is not used}}
};
class FriendEqDefaultCompare {
+ int used;
friend auto operator==(FriendEqDefaultCompare, FriendEqDefaultCompare) ->
bool = default;
};
+class UnrelatedFriendEqDefaultCompare {
+ friend auto operator==(UnrelatedFriendEqDefaultCompare,
UnrelatedFriendEqDefaultCompare) -> bool = default;
+ int operator<=>(const UnrelatedFriendEqDefaultCompare &) const = default;
+};
+
#endif
class NotFullyDefined {
>From d95b9d995a19c10d394474fd67cde4d834476cad Mon Sep 17 00:00:00 2001
From: Chris White <chriswhiteio...@gmail.com>
Date: Sat, 23 Nov 2024 14:55:47 +0000
Subject: [PATCH 3/3] Update release notes
---
clang/docs/ReleaseNotes.rst | 14 ++++++++++++++
clang/test/SemaCXX/warn-unused-private-field.cpp | 7 -------
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 191b4cc0ce07ad..30fbdc9769c958 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -641,6 +641,20 @@ Improvements to Clang's diagnostics
- Clang now diagnoses dangling references for C++20's parenthesized aggregate
initialization (#101957).
+- Fixed a bug where Clang would not emit ``-Wunused-private-field`` warnings
when an unrelated class
+ defined a defaulted comparison operator (#GH116270).
+
+ .. code-block:: c++
+
+ class A {
+ private:
+ int a; // warning: private field 'a' is not used, no diagnostic
previously
+ };
+
+ class C {
+ bool operator==(const C&) = default;
+ };
+
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 9eccfc20430439..0cc6f687f1b35f 100644
--- a/clang/test/SemaCXX/warn-unused-private-field.cpp
+++ b/clang/test/SemaCXX/warn-unused-private-field.cpp
@@ -40,13 +40,6 @@ class FriendEqDefaultCompareOutOfClass {
bool operator==(const FriendEqDefaultCompareOutOfClass &, const
FriendEqDefaultCompareOutOfClass &) = default;
-class UnusedConstPrivateField {
-public:
- UnusedConstPrivateField() : unused_(0) {}
-private:
- const int unused_; // expected-warning{{private field 'unused_' is not
used}}
-};
-
class HasUnusedField {
int unused_; // expected-warning{{private field 'unused_' is not used}}
};
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