[clang] [Clang][Sema] Abbreviated function templates do not append invented parameters to empty template parameter lists (PR #80864)
Krystian Stasiowski via cfe-commits
cfe-commits at lists.llvm.org
Tue Feb 6 08:32:53 PST 2024
https://github.com/sdkrystian updated https://github.com/llvm/llvm-project/pull/80864
>From 570e25f19b428fb7d2936091726727f9633eec35 Mon Sep 17 00:00:00 2001
From: Krystian Stasiowski <sdkrystian at gmail.com>
Date: Tue, 6 Feb 2024 11:08:04 -0500
Subject: [PATCH 1/2] [Clang][Sema] Abbreviated function templates do not
append invented parameters to empty template parameter lists
---
clang/docs/ReleaseNotes.rst | 2 ++
clang/lib/Sema/SemaDecl.cpp | 2 +-
clang/lib/Sema/SemaDeclCXX.cpp | 11 ++++++++-
.../CXX/dcl.decl/dcl.meaning/dcl.fct/p23.cpp | 24 +++++++++++++++++++
4 files changed, 37 insertions(+), 2 deletions(-)
create mode 100644 clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p23.cpp
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 4d57ea4fd55b8c..d0ba986601e92f 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -204,6 +204,8 @@ Bug Fixes to C++ Support
parameter where we did an incorrect specialization of the initialization of
the default parameter.
Fixes (`#68490 <https://github.com/llvm/llvm-project/issues/68490>`_)
+- Fixed a bug where abbreviated function templates would append their invented template parameters to
+ an empty template parameter lists.
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 481d952d2389bb..d9704e5bfd67c8 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9759,7 +9759,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
SmallVector<TemplateParameterList *, 4> TemplateParamLists;
llvm::append_range(TemplateParamLists, TemplateParamListsRef);
if (TemplateParameterList *Invented = D.getInventedTemplateParameterList()) {
- if (!TemplateParamLists.empty() &&
+ if (!TemplateParamLists.empty() && TemplateParamLists.back()->size() &&
Invented->getDepth() == TemplateParamLists.back()->getDepth())
TemplateParamLists.back() = Invented;
else
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index ab8a967b06a456..f34893d88a3b3f 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -19294,7 +19294,16 @@ void Sema::ActOnStartFunctionDeclarationDeclarator(
ExplicitLists, /*IsFriend=*/false, IsMemberSpecialization, IsInvalid,
/*SuppressDiagnostic=*/true);
}
- if (ExplicitParams) {
+ // C++23 [dcl.fct]p23:
+ // An abbreviated function template can have a template-head. The invented
+ // template-parameters are appended to the template-parameter-list after
+ // the explicitly declared template-parameters.
+ //
+ // A template-head must have one or more template-parameters (read:
+ // 'template<>' is *not* a template-head). Only append the invented
+ // template parameters if we matched the nested-name-specifier to a non-empty
+ // TemplateParameterList.
+ if (ExplicitParams && ExplicitParams->size()) {
Info.AutoTemplateParameterDepth = ExplicitParams->getDepth();
llvm::append_range(Info.TemplateParams, *ExplicitParams);
Info.NumExplicitTemplateParams = ExplicitParams->size();
diff --git a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p23.cpp b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p23.cpp
new file mode 100644
index 00000000000000..469c4e091953c3
--- /dev/null
+++ b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p23.cpp
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -std=c++20 -pedantic-errors -verify %s
+
+// FIXME: This should be an error with -pedantic-errors.
+template<> // expected-warning {{extraneous template parameter list in template specialization}}
+void f(auto);
+
+template<typename>
+void f(auto);
+
+template<typename T>
+struct A {
+ void g(auto);
+};
+
+template<typename T>
+void A<T>::g(auto) { }
+
+template<>
+void A<int>::g(auto) { }
+
+// FIXME: This should be an error with -pedantic-errors.
+template<>
+template<> // expected-warning {{extraneous template parameter list in template specialization}}
+void A<long>::g(auto) { }
>From 0037ab6bc32106d1eecccb1ad662bf4ca217555c Mon Sep 17 00:00:00 2001
From: Krystian Stasiowski <sdkrystian at gmail.com>
Date: Tue, 6 Feb 2024 11:32:41 -0500
Subject: [PATCH 2/2] [FOLD]
---
clang/include/clang/AST/DeclTemplate.h | 1 +
clang/lib/Sema/SemaDecl.cpp | 2 +-
clang/lib/Sema/SemaDeclCXX.cpp | 2 +-
3 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
index baf71145d99dc6..e3b6a7efb1127a 100644
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -134,6 +134,7 @@ class TemplateParameterList final
const_iterator end() const { return begin() + NumParams; }
unsigned size() const { return NumParams; }
+ bool empty() const { return NumParams == 0; }
ArrayRef<NamedDecl *> asArray() { return llvm::ArrayRef(begin(), end()); }
ArrayRef<const NamedDecl*> asArray() const {
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index d9704e5bfd67c8..4c4468d94f28d7 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9759,7 +9759,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
SmallVector<TemplateParameterList *, 4> TemplateParamLists;
llvm::append_range(TemplateParamLists, TemplateParamListsRef);
if (TemplateParameterList *Invented = D.getInventedTemplateParameterList()) {
- if (!TemplateParamLists.empty() && TemplateParamLists.back()->size() &&
+ if (!TemplateParamLists.empty() && !TemplateParamLists.back()->empty() &&
Invented->getDepth() == TemplateParamLists.back()->getDepth())
TemplateParamLists.back() = Invented;
else
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index f34893d88a3b3f..fea8c5036c80b1 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -19303,7 +19303,7 @@ void Sema::ActOnStartFunctionDeclarationDeclarator(
// 'template<>' is *not* a template-head). Only append the invented
// template parameters if we matched the nested-name-specifier to a non-empty
// TemplateParameterList.
- if (ExplicitParams && ExplicitParams->size()) {
+ if (ExplicitParams && !ExplicitParams->empty()) {
Info.AutoTemplateParameterDepth = ExplicitParams->getDepth();
llvm::append_range(Info.TemplateParams, *ExplicitParams);
Info.NumExplicitTemplateParams = ExplicitParams->size();
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