https://github.com/ecnelises created
https://github.com/llvm/llvm-project/pull/71696
If return type of overriden method is pointer or reference to non-class type,
qualifiers cannot be dropped. This also fixes check when qualifier of overriden
method's class return type is not subset of super method's.
Fixes #18233
>From 1d0109b7f370a3689a92e20ab52597b112669e47 Mon Sep 17 00:00:00 2001
From: Qiu Chaofan <qiuco...@cn.ibm.com>
Date: Thu, 9 Nov 2023 00:00:26 +0800
Subject: [PATCH] [Clang][Sema] Fix qualifier restriction of overriden methods
If return type of overriden method is pointer or reference to
non-class type, qualifiers cannot be dropped. This also fixes check
when qualifier of overriden method's class return type is not subset
of super method's.
---
.../clang/Basic/DiagnosticSemaKinds.td | 2 +-
clang/lib/Sema/SemaDeclCXX.cpp | 15 +++++++++-
clang/test/SemaCXX/virtual-override.cpp | 28 ++++++++++++++++++-
3 files changed, 42 insertions(+), 3 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 18c2e861385e463..e60a7513d54e552 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2115,7 +2115,7 @@ def err_covariant_return_type_different_qualifications :
Error<
def err_covariant_return_type_class_type_more_qualified : Error<
"return type of virtual function %0 is not covariant with the return type of
"
"the function it overrides (class type %1 is more qualified than class "
- "type %2">;
+ "type %2)">;
// C++ implicit special member functions
def note_in_declaration_of_implicit_special_member : Note<
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 60786a880b9d3fd..b2c1f1fff9d7e7b 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -18469,7 +18469,7 @@ bool Sema::CheckOverridingFunctionReturnType(const
CXXMethodDecl *New,
// The new class type must have the same or less qualifiers as the old type.
- if (NewClassTy.isMoreQualifiedThan(OldClassTy)) {
+ if (!OldClassTy.isAtLeastAsQualifiedAs(NewClassTy)) {
Diag(New->getLocation(),
diag::err_covariant_return_type_class_type_more_qualified)
<< New->getDeclName() << NewTy << OldTy
@@ -18479,6 +18479,19 @@ bool Sema::CheckOverridingFunctionReturnType(const
CXXMethodDecl *New,
return true;
}
+ // Non-class return types should not drop qualifiers in overriden method.
+ if (!OldClassTy->isStructureOrClassType() &&
+ OldClassTy.getLocalCVRQualifiers() !=
+ NewClassTy.getLocalCVRQualifiers()) {
+ Diag(New->getLocation(),
+ diag::err_covariant_return_type_different_qualifications)
+ << New->getDeclName() << NewTy << OldTy
+ << New->getReturnTypeSourceRange();
+ Diag(Old->getLocation(), diag::note_overridden_virtual_function)
+ << Old->getReturnTypeSourceRange();
+ return true;
+ }
+
return false;
}
diff --git a/clang/test/SemaCXX/virtual-override.cpp
b/clang/test/SemaCXX/virtual-override.cpp
index 72abfc3cf51e1f7..003f4826a3d6c86 100644
--- a/clang/test/SemaCXX/virtual-override.cpp
+++ b/clang/test/SemaCXX/virtual-override.cpp
@@ -87,7 +87,7 @@ class A {
class B : A {
virtual a* f();
- virtual const a* g(); // expected-error{{return type of virtual function 'g'
is not covariant with the return type of the function it overrides (class type
'const a *' is more qualified than class type 'a *'}}
+ virtual const a* g(); // expected-error{{return type of virtual function 'g'
is not covariant with the return type of the function it overrides (class type
'const a *' is more qualified than class type 'a *')}}
};
}
@@ -289,3 +289,29 @@ namespace PR8168 {
static void foo() {} // expected-error{{'static' member function 'foo'
overrides a virtual function}}
};
}
+
+namespace T13 {
+ class A {
+ public:
+ virtual const int* foo(); // expected-note{{overridden virtual function is
here}}
+ };
+
+ class B: public A {
+ public:
+ virtual int* foo(); // expected-error{{return type of virtual function
'foo' is not covariant with the return type of the function it overrides ('int
*' has different qualifiers than 'const int *')}}
+ };
+}
+
+namespace T14 {
+ struct a {};
+
+ class A {
+ public:
+ virtual const a* foo(); // expected-note{{overridden virtual function is
here}}
+ };
+
+ class B: public A {
+ public:
+ virtual volatile a* foo(); // expected-error{{return type of virtual
function 'foo' is not covariant with the return type of the function it
overrides (class type 'volatile a *' is more qualified than class type 'const a
*')}}
+ };
+}
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