[clang] [Clang] Disallow explicit object parameters in more contexts (PR #89078)
via cfe-commits
cfe-commits at lists.llvm.org
Tue Apr 23 10:10:54 PDT 2024
https://github.com/Sirraide updated https://github.com/llvm/llvm-project/pull/89078
>From c611122688657287e8285edd9a2875e4975d26dd Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Wed, 17 Apr 2024 16:15:39 +0200
Subject: [PATCH 1/6] [Clang] Disallow explicit object parameters in more
contexts
---
.../clang/Basic/DiagnosticSemaKinds.td | 2 ++
clang/lib/Sema/SemaDeclCXX.cpp | 6 ++--
clang/lib/Sema/SemaType.cpp | 30 +++++++++++++++++++
clang/test/SemaCXX/cxx2b-deducing-this.cpp | 22 ++++++++++++--
4 files changed, 54 insertions(+), 6 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 5ec0218aedfe86..680638d2e59c6a 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7494,6 +7494,8 @@ def err_explicit_object_parameter_mutable: Error<
def err_invalid_explicit_object_type_in_lambda: Error<
"invalid explicit object parameter type %0 in lambda with capture; "
"the type must be the same as, or derived from, the lambda">;
+def err_explicit_object_parameter_invalid: Error<
+ "an explicit object parameter is not allowed here">;
def err_ref_qualifier_overload : Error<
"cannot overload a member function %select{without a ref-qualifier|with "
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 7669171fea56ff..ea634df48e5deb 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -11469,10 +11469,8 @@ void Sema::CheckExplicitObjectMemberFunction(Declarator &D,
return;
if (!DC || !DC->isRecord()) {
- Diag(ExplicitObjectParam->getLocation(),
- diag::err_explicit_object_parameter_nonmember)
- << D.getSourceRange() << /*non-member=*/2 << IsLambda;
- D.setInvalidType();
+ assert(D.isInvalidType() && "Explicit object parameter in non-member "
+ "should have been diagnosed already");
return;
}
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 404c4e8e31b558..406065741bf2d9 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5287,6 +5287,36 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// Check for auto functions and trailing return type and adjust the
// return type accordingly.
if (!D.isInvalidType()) {
+ // [dcl.fct]p6:
+ //
+ // An explicit-object-parameter-declaration is a parameter-declaration
+ // with a this specifier. An explicit-object-parameter-declaration shall
+ // appear only as the first parameter-declaration of a
+ // parameter-declaration-list of either:
+ //
+ // - a member-declarator that declares a member function [class.mem], or
+ // - a lambda-declarator [expr.prim.lambda].
+ DeclaratorContext C = D.getContext();
+ ParmVarDecl *First =
+ FTI.NumParams
+ ? dyn_cast_if_present<ParmVarDecl>(FTI.Params[0].Param)
+ : nullptr;
+ if (First && First->isExplicitObjectParameter() &&
+ C != DeclaratorContext::LambdaExpr &&
+
+ // Either not a member or nested declarator in a member.
+ (C != DeclaratorContext::Member ||
+ D.getInnermostNonParenChunk() != &DeclType) &&
+
+ // Allow out-of-line definitions if we have a scope spec.
+ D.getCXXScopeSpec().isEmpty()) {
+ S.Diag(First->getBeginLoc(),
+ diag::err_explicit_object_parameter_invalid)
+ << First->getSourceRange();
+ D.setInvalidType();
+ AreDeclaratorChunksValid = false;
+ }
+
// trailing-return-type is only required if we're declaring a function,
// and not, for instance, a pointer to a function.
if (D.getDeclSpec().hasAutoTypeSpec() &&
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index 5f29a955e053c3..ddb770a92db0f9 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -5,7 +5,7 @@
void f(this); // expected-error{{variable has incomplete type 'void'}} \
// expected-error{{invalid use of 'this' outside of a non-static member function}}
-void g(this auto); // expected-error{{an explicit object parameter cannot appear in a non-member function}}
+void g(this auto); // expected-error{{an explicit object parameter is not allowed here}}
auto l1 = [] (this auto) static {}; // expected-error{{an explicit object parameter cannot appear in a static lambda}}
auto l2 = [] (this auto) mutable {}; // expected-error{{a lambda with an explicit object parameter cannot be mutable}}
@@ -685,7 +685,7 @@ struct S {
static void j(this S s); // expected-error {{an explicit object parameter cannot appear in a static function}}
};
-void nonmember(this S s); // expected-error {{an explicit object parameter cannot appear in a non-member function}}
+void nonmember(this S s); // expected-error {{an explicit object parameter is not allowed here}}
int test() {
S s;
@@ -838,3 +838,21 @@ int h() {
}();
}
}
+
+namespace GH85992 {
+struct S {
+ int (S::*x)(this int); // expected-error {{an explicit object parameter is not allowed here}}
+ int (*y)(this int); // expected-error {{an explicit object parameter is not allowed here}}
+ int (***z)(this int); // expected-error {{an explicit object parameter is not allowed here}}
+
+ int f(this S);
+ int ((g))(this S);
+ int h(int x, int (*)(this S)); // expected-error {{an explicit object parameter is not allowed here}}
+};
+
+using T = int (*)(this int); // expected-error {{an explicit object parameter is not allowed here}}
+using U = int (S::*)(this int); // expected-error {{an explicit object parameter is not allowed here}}
+int h(this int); // expected-error {{an explicit object parameter is not allowed here}}
+
+int S::f(this S) { return 1; }
+}
>From c27a3ff93474bc890de2b66ab7f486bb59e3b6d8 Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Wed, 17 Apr 2024 16:16:47 +0200
Subject: [PATCH 2/6] [NFC] clang-format
---
clang/lib/Sema/SemaType.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 406065741bf2d9..23f2b9d74931bd 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5294,7 +5294,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// appear only as the first parameter-declaration of a
// parameter-declaration-list of either:
//
- // - a member-declarator that declares a member function [class.mem], or
+ // - a member-declarator that declares a member function [class.mem],
+ // or
// - a lambda-declarator [expr.prim.lambda].
DeclaratorContext C = D.getContext();
ParmVarDecl *First =
>From 0c1239a85159aaa4958bb574a326e85f50719b1b Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Wed, 17 Apr 2024 16:23:15 +0200
Subject: [PATCH 3/6] [NFC] Reformat comment
---
clang/lib/Sema/SemaType.cpp | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 23f2b9d74931bd..95257b801c8a6c 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5294,9 +5294,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// appear only as the first parameter-declaration of a
// parameter-declaration-list of either:
//
- // - a member-declarator that declares a member function [class.mem],
- // or
- // - a lambda-declarator [expr.prim.lambda].
+ // - a member-declarator that declares a member function [class.mem], or
+ // - a lambda-declarator [expr.prim.lambda].
DeclaratorContext C = D.getContext();
ParmVarDecl *First =
FTI.NumParams
>From 8edd57fd41c5c62de628b8ea9cf6b0ff1e4bc535 Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Tue, 23 Apr 2024 18:25:04 +0200
Subject: [PATCH 4/6] [Clang] Check that the NNS is a class type
---
clang/lib/Sema/SemaType.cpp | 9 ++++++++-
clang/test/SemaCXX/cxx2b-deducing-this.cpp | 5 +++++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 95257b801c8a6c..d8b74b640af40a 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5287,6 +5287,13 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// Check for auto functions and trailing return type and adjust the
// return type accordingly.
if (!D.isInvalidType()) {
+ auto isClassType = [&](CXXScopeSpec& SS) {
+ // If there already was an problem with the scope; don’t issue another
+ // error about the explicit object parameter.
+ return SS.isInvalid() ||
+ isa_and_present<CXXRecordDecl>(S.computeDeclContext(SS));
+ };
+
// [dcl.fct]p6:
//
// An explicit-object-parameter-declaration is a parameter-declaration
@@ -5309,7 +5316,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
D.getInnermostNonParenChunk() != &DeclType) &&
// Allow out-of-line definitions if we have a scope spec.
- D.getCXXScopeSpec().isEmpty()) {
+ !isClassType(D.getCXXScopeSpec())) {
S.Diag(First->getBeginLoc(),
diag::err_explicit_object_parameter_invalid)
<< First->getSourceRange();
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index ddb770a92db0f9..d2c47b77365cd8 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -855,4 +855,9 @@ using U = int (S::*)(this int); // expected-error {{an explicit object parameter
int h(this int); // expected-error {{an explicit object parameter is not allowed here}}
int S::f(this S) { return 1; }
+
+namespace a {
+void f();
+};
+void a::f(this auto) {} // expected-error {{an explicit object parameter is not allowed here}}
}
>From 9c0609cf787cf00685d05ecabf707a885a77cc73 Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Tue, 23 Apr 2024 19:09:45 +0200
Subject: [PATCH 5/6] [Clang] Handle friends and restore better diagnostic
---
clang/lib/Sema/SemaDeclCXX.cpp | 17 +++++++++++++++++
clang/lib/Sema/SemaType.cpp | 22 +++++++++++++++++-----
clang/test/SemaCXX/cxx2b-deducing-this.cpp | 15 +++++++++++----
3 files changed, 45 insertions(+), 9 deletions(-)
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index ea634df48e5deb..1333f8492b40d4 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -11459,6 +11459,23 @@ void Sema::CheckExplicitObjectMemberFunction(Declarator &D,
D.setInvalidType();
}
+ // Handle the following case:
+ //
+ // struct S {
+ // struct T {
+ // int f(this T);
+ // };
+ //
+ // friend int T::f(this T); // Allow this.
+ // friend int f(this S); // But disallow this.
+ // };
+ if (D.getDeclSpec().isFriendSpecified() && D.getCXXScopeSpec().isEmpty()) {
+ Diag(ExplicitObjectParam->getBeginLoc(),
+ diag::err_explicit_object_parameter_nonmember)
+ << D.getSourceRange() << /*non-member=*/2 << IsLambda;
+ D.setInvalidType();
+ }
+
if (IsLambda && FTI.hasMutableQualifier()) {
Diag(ExplicitObjectParam->getBeginLoc(),
diag::err_explicit_object_parameter_mutable)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index d8b74b640af40a..2c2bdb503a34ca 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5308,18 +5308,30 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
FTI.NumParams
? dyn_cast_if_present<ParmVarDecl>(FTI.Params[0].Param)
: nullptr;
+
+ auto IsFunctionDecl = D.getInnermostNonParenChunk() == &DeclType;
if (First && First->isExplicitObjectParameter() &&
C != DeclaratorContext::LambdaExpr &&
// Either not a member or nested declarator in a member.
- (C != DeclaratorContext::Member ||
- D.getInnermostNonParenChunk() != &DeclType) &&
+ //
+ // Note that e.g. 'static' or 'friend' declarations are accepted
+ // here; we diagnose them later when we build the member function
+ // because it's easier that way.
+ (C != DeclaratorContext::Member || !IsFunctionDecl) &&
// Allow out-of-line definitions if we have a scope spec.
!isClassType(D.getCXXScopeSpec())) {
- S.Diag(First->getBeginLoc(),
- diag::err_explicit_object_parameter_invalid)
- << First->getSourceRange();
+ if (IsFunctionDecl)
+ S.Diag(First->getBeginLoc(),
+ diag::err_explicit_object_parameter_nonmember)
+ << /*non-member*/ 2 << /*function*/ 0
+ << First->getSourceRange();
+ else
+ S.Diag(First->getBeginLoc(),
+ diag::err_explicit_object_parameter_invalid)
+ << First->getSourceRange();
+
D.setInvalidType();
AreDeclaratorChunksValid = false;
}
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index d2c47b77365cd8..48f963acc27e61 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -5,7 +5,7 @@
void f(this); // expected-error{{variable has incomplete type 'void'}} \
// expected-error{{invalid use of 'this' outside of a non-static member function}}
-void g(this auto); // expected-error{{an explicit object parameter is not allowed here}}
+void g(this auto); // expected-error{{an explicit object parameter cannot appear in a non-member function}}
auto l1 = [] (this auto) static {}; // expected-error{{an explicit object parameter cannot appear in a static lambda}}
auto l2 = [] (this auto) mutable {}; // expected-error{{a lambda with an explicit object parameter cannot be mutable}}
@@ -685,7 +685,7 @@ struct S {
static void j(this S s); // expected-error {{an explicit object parameter cannot appear in a static function}}
};
-void nonmember(this S s); // expected-error {{an explicit object parameter is not allowed here}}
+void nonmember(this S s); // expected-error{{an explicit object parameter cannot appear in a non-member function}}
int test() {
S s;
@@ -847,17 +847,24 @@ struct S {
int f(this S);
int ((g))(this S);
+ friend int h(this S); // expected-error {{an explicit object parameter cannot appear in a non-member function}}
int h(int x, int (*)(this S)); // expected-error {{an explicit object parameter is not allowed here}}
+
+ struct T {
+ int f(this T);
+ };
+
+ friend int T::f(this T);
};
using T = int (*)(this int); // expected-error {{an explicit object parameter is not allowed here}}
using U = int (S::*)(this int); // expected-error {{an explicit object parameter is not allowed here}}
-int h(this int); // expected-error {{an explicit object parameter is not allowed here}}
+int h(this int); // expected-error {{an explicit object parameter cannot appear in a non-member function}}
int S::f(this S) { return 1; }
namespace a {
void f();
};
-void a::f(this auto) {} // expected-error {{an explicit object parameter is not allowed here}}
+void a::f(this auto) {} // expected-error {{an explicit object parameter cannot appear in a non-member function}}
}
>From 853da04fe387f56fa69a468342bb665381db2b79 Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Tue, 23 Apr 2024 19:10:11 +0200
Subject: [PATCH 6/6] [NFC] clang-format
---
clang/lib/Sema/SemaType.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 2c2bdb503a34ca..6a7754dce96d76 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5287,7 +5287,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// Check for auto functions and trailing return type and adjust the
// return type accordingly.
if (!D.isInvalidType()) {
- auto isClassType = [&](CXXScopeSpec& SS) {
+ auto isClassType = [&](CXXScopeSpec &SS) {
// If there already was an problem with the scope; don’t issue another
// error about the explicit object parameter.
return SS.isInvalid() ||
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