[clang] a1a6a83 - [clang] fix matching of nested template template parameters (#130447)
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cfe-commits at lists.llvm.org
Mon Mar 10 06:08:46 PDT 2025
Author: Matheus Izvekov
Date: 2025-03-10T10:08:43-03:00
New Revision: a1a6a839763079b54d8910599549b9e6d4dd5fe6
URL: https://github.com/llvm/llvm-project/commit/a1a6a839763079b54d8910599549b9e6d4dd5fe6
DIFF: https://github.com/llvm/llvm-project/commit/a1a6a839763079b54d8910599549b9e6d4dd5fe6.diff
LOG: [clang] fix matching of nested template template parameters (#130447)
When checking the template template parameters of template template
parameters, the PartialOrdering context was not correctly propagated.
This also has a few drive-by fixes, such as checking the template
parameter lists of template template parameters, which was previously
missing and would have been it's own bug, but we need to fix it in order
to prevent crashes in error recovery in a simple way.
Fixes #130362
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaDeclCXX.cpp
clang/lib/Sema/SemaTemplate.cpp
clang/lib/Sema/SemaTemplateDeduction.cpp
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
clang/test/SemaTemplate/cwg2398.cpp
clang/test/SemaTemplate/temp_arg_template_p0522.cpp
clang/unittests/AST/DeclPrinterTest.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7b254b371e5fa..5a2704cdf865e 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -292,6 +292,9 @@ Bug Fixes to C++ Support
direct-list-initialized from an array is corrected to direct-initialization.
- Clang no longer crashes when a coroutine is declared ``[[noreturn]]``. (#GH127327)
- Clang now uses the parameter location for abbreviated function templates in ``extern "C"``. (#GH46386)
+- Fixes matching of nested template template parameters. (#GH130362)
+- Correctly diagnoses template template paramters which have a pack parameter
+ not in the last position.
- Clang now correctly parses ``if constexpr`` expressions in immediate function context. (#GH123524)
Bug Fixes to AST Handling
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 159c908a1b26c..9a312e1c55f60 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -11356,14 +11356,16 @@ class Sema final : public SemaBase {
/// The context in which we are checking a template parameter list.
enum TemplateParamListContext {
- TPC_ClassTemplate,
- TPC_VarTemplate,
+ // For this context, Class, Variable, TypeAlias, and non-pack Template
+ // Template Parameters are treated uniformly.
+ TPC_Other,
+
TPC_FunctionTemplate,
TPC_ClassTemplateMember,
TPC_FriendClassTemplate,
TPC_FriendFunctionTemplate,
TPC_FriendFunctionTemplateDefinition,
- TPC_TypeAliasTemplate
+ TPC_TemplateTemplateParameterPack,
};
/// Checks the validity of a template parameter list, possibly
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9d102abb17c19..dcb419fdd6f1b 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8154,7 +8154,7 @@ NamedDecl *Sema::ActOnVariableDeclarator(
(D.getCXXScopeSpec().isSet() && DC && DC->isRecord() &&
DC->isDependentContext())
? TPC_ClassTemplateMember
- : TPC_VarTemplate))
+ : TPC_Other))
NewVD->setInvalidDecl();
// If we are providing an explicit specialization of a static variable
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index fd5f0443fa894..1edbe62f1c79a 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -13586,7 +13586,7 @@ Decl *Sema::ActOnAliasDeclaration(Scope *S, AccessSpecifier AS,
// Merge any previous default template arguments into our parameters,
// and check the parameter list.
if (CheckTemplateParameterList(TemplateParams, OldTemplateParams,
- TPC_TypeAliasTemplate))
+ TPC_Other))
return nullptr;
TypeAliasTemplateDecl *NewDecl =
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index dfd7a55ce63be..290862d9a773d 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1591,8 +1591,16 @@ NamedDecl *Sema::ActOnTemplateTemplateParameter(
assert(S->isTemplateParamScope() &&
"Template template parameter not in template parameter scope!");
- // Construct the parameter object.
bool IsParameterPack = EllipsisLoc.isValid();
+
+ bool Invalid = false;
+ if (CheckTemplateParameterList(
+ Params,
+ /*OldParams=*/nullptr,
+ IsParameterPack ? TPC_TemplateTemplateParameterPack : TPC_Other))
+ Invalid = true;
+
+ // Construct the parameter object.
TemplateTemplateParmDecl *Param = TemplateTemplateParmDecl::Create(
Context, Context.getTranslationUnitDecl(),
NameLoc.isInvalid() ? TmpLoc : NameLoc, Depth, Position, IsParameterPack,
@@ -1615,9 +1623,12 @@ NamedDecl *Sema::ActOnTemplateTemplateParameter(
if (Params->size() == 0) {
Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
<< SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
- Param->setInvalidDecl();
+ Invalid = true;
}
+ if (Invalid)
+ Param->setInvalidDecl();
+
// C++0x [temp.param]p9:
// A default template-argument may be specified for any kind of
// template-parameter that is not a template parameter pack.
@@ -2066,7 +2077,7 @@ DeclResult Sema::CheckClassTemplate(
SemanticContext->isDependentContext())
? TPC_ClassTemplateMember
: TUK == TagUseKind::Friend ? TPC_FriendClassTemplate
- : TPC_ClassTemplate,
+ : TPC_Other,
SkipBody))
Invalid = true;
@@ -2208,9 +2219,8 @@ static bool DiagnoseDefaultTemplateArgument(Sema &S,
SourceLocation ParamLoc,
SourceRange DefArgRange) {
switch (TPC) {
- case Sema::TPC_ClassTemplate:
- case Sema::TPC_VarTemplate:
- case Sema::TPC_TypeAliasTemplate:
+ case Sema::TPC_Other:
+ case Sema::TPC_TemplateTemplateParameterPack:
return false;
case Sema::TPC_FunctionTemplate:
@@ -2383,8 +2393,11 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
MissingDefaultArg = true;
} else if (NonTypeTemplateParmDecl *NewNonTypeParm
= dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
- // Check for unexpanded parameter packs.
- if (!NewNonTypeParm->isParameterPack() &&
+ // Check for unexpanded parameter packs, except in a template template
+ // parameter pack, as in those any unexpanded packs should be expanded
+ // along with the parameter itself.
+ if (TPC != TPC_TemplateTemplateParameterPack &&
+ !NewNonTypeParm->isParameterPack() &&
DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
NewNonTypeParm->getTypeSourceInfo(),
UPPC_NonTypeTemplateParameterType)) {
@@ -2492,8 +2505,7 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
// If a template parameter of a primary class template or alias template
// is a template parameter pack, it shall be the last template parameter.
if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
- (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
- TPC == TPC_TypeAliasTemplate)) {
+ (TPC == TPC_Other || TPC == TPC_TemplateTemplateParameterPack)) {
Diag((*NewParam)->getLocation(),
diag::err_template_param_pack_must_be_last_template_parameter);
Invalid = true;
@@ -2526,8 +2538,8 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
<< PrevModuleName;
Invalid = true;
} else if (MissingDefaultArg &&
- (TPC == TPC_ClassTemplate || TPC == TPC_FriendClassTemplate ||
- TPC == TPC_VarTemplate || TPC == TPC_TypeAliasTemplate)) {
+ (TPC == TPC_Other || TPC == TPC_TemplateTemplateParameterPack ||
+ TPC == TPC_FriendClassTemplate)) {
// C++ 23[temp.param]p14:
// If a template-parameter of a class template, variable template, or
// alias template has a default template argument, each subsequent
diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index 9769848840d87..e6ec4a7178e81 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -3427,9 +3427,9 @@ static TemplateDeductionResult FinishTemplateArgumentDeduction(
if (!P.isPackExpansion() && !A.isPackExpansion()) {
Info.Param =
makeTemplateParameter(Template->getTemplateParameters()->getParam(
- (PsStack.empty() ? TemplateArgs.end()
- : PsStack.front().begin()) -
- TemplateArgs.begin()));
+ (AsStack.empty() ? CTAI.CanonicalConverted.end()
+ : AsStack.front().begin()) -
+ 1 - CTAI.CanonicalConverted.begin()));
Info.FirstArg = P;
Info.SecondArg = A;
return TemplateDeductionResult::NonDeducedMismatch;
@@ -6642,17 +6642,19 @@ bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs(
TemplateDeductionResult TDK;
runWithSufficientStackSpace(Info.getLocation(), [&] {
- TDK = ::FinishTemplateArgumentDeduction(
- *this, AArg, /*IsPartialOrdering=*/true, PArgs, Deduced, Info);
+ TDK = ::FinishTemplateArgumentDeduction(*this, AArg, PartialOrdering, PArgs,
+ Deduced, Info);
});
switch (TDK) {
case TemplateDeductionResult::Success:
return true;
// It doesn't seem possible to get a non-deduced mismatch when partial
- // ordering TTPs.
+ // ordering TTPs, except with an invalid template parameter list which has
+ // a parameter after a pack.
case TemplateDeductionResult::NonDeducedMismatch:
- llvm_unreachable("Unexpected NonDeducedMismatch");
+ assert(PArg->isInvalidDecl() && "Unexpected NonDeducedMismatch");
+ return false;
// Substitution failures should have already been diagnosed.
case TemplateDeductionResult::AlreadyDiagnosed:
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index cb434dcf6eb9a..a231ad72a9e7c 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2176,7 +2176,7 @@ Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
// Do some additional validation, then merge default arguments
// from the existing declarations.
if (SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
- Sema::TPC_ClassTemplate))
+ Sema::TPC_Other))
return nullptr;
Inst->setAccess(PrevClassTemplate->getAccess());
diff --git a/clang/test/SemaTemplate/cwg2398.cpp b/clang/test/SemaTemplate/cwg2398.cpp
index 51d98d4b3b202..06333c81a603e 100644
--- a/clang/test/SemaTemplate/cwg2398.cpp
+++ b/clang/test/SemaTemplate/cwg2398.cpp
@@ -602,6 +602,11 @@ namespace regression3 {
template <class...> class B {};
template struct A<B, Node<None>>;
} // namespace regression3
+namespace GH130362 {
+ template <template <template <class... T1> class TT1> class TT2> struct A {};
+ template <template <class U1> class UU1> struct B {};
+ template struct A<B>;
+} // namespace GH130362
namespace nttp_auto {
namespace t1 {
@@ -610,24 +615,16 @@ namespace nttp_auto {
template struct A<B>;
} // namespace t1
namespace t2 {
- // FIXME: Shouldn't accept parameters after a parameter pack.
template<template<auto... Va1, auto Va2> class> struct A {};
- // expected-error at -1 {{deduced non-type template argument does not have the same type as the corresponding template parameter ('auto' vs 'int')}}
- // expected-note at -2 {{previous template template parameter is here}}
+ // expected-error at -1 {{template parameter pack must be the last template parameter}}
template<int... Vi> struct B;
- // expected-note at -1 {{template parameter is declared here}}
template struct A<B>;
- // expected-note at -1 {{
diff erent template parameters}}
} // namespace t2
namespace t3 {
- // FIXME: Shouldn't accept parameters after a parameter pack.
template<template<auto... Va1, auto... Va2> class> struct A {};
- // expected-error at -1 {{deduced non-type template argument does not have the same type as the corresponding template parameter ('auto' vs 'int')}}
- // expected-note at -2 {{previous template template parameter is here}}
+ // expected-error at -1 {{template parameter pack must be the last template parameter}}
template<int... Vi> struct B;
- // expected-note at -1 {{template parameter is declared here}}
template struct A<B>;
- // expected-note at -1 {{
diff erent template parameters}}
} // namespace t3
} // namespace nttp_auto
diff --git a/clang/test/SemaTemplate/temp_arg_template_p0522.cpp b/clang/test/SemaTemplate/temp_arg_template_p0522.cpp
index 2e5a36ae6ed08..d8a81bb363112 100644
--- a/clang/test/SemaTemplate/temp_arg_template_p0522.cpp
+++ b/clang/test/SemaTemplate/temp_arg_template_p0522.cpp
@@ -7,7 +7,8 @@
template<template<int> typename> struct Ti; // #Ti
template<template<int...> typename> struct TPi; // #TPi
template<template<int, int...> typename> struct TiPi;
-template<template<int..., int...> typename> struct TPiPi; // FIXME: Why is this not ill-formed?
+template<template<int..., int...> typename> struct TPiPi;
+// expected-error at -1 {{template parameter pack must be the last template parameter}}
template<typename T, template<T> typename> struct tT0; // #tT0
template<template<typename T, T> typename> struct Tt0; // #Tt0
diff --git a/clang/unittests/AST/DeclPrinterTest.cpp b/clang/unittests/AST/DeclPrinterTest.cpp
index 6945dff537cae..124b1a166cb18 100644
--- a/clang/unittests/AST/DeclPrinterTest.cpp
+++ b/clang/unittests/AST/DeclPrinterTest.cpp
@@ -1196,21 +1196,21 @@ TEST(DeclPrinter, TestUnnamedTemplateParameters) {
}
TEST(DeclPrinter, TestUnnamedTemplateParametersPacks) {
- ASSERT_TRUE(PrintedDeclCXX17Matches(
- "template <typename ..., int ...,"
- " template <typename ..., bool ...> class ...> void A();",
- functionTemplateDecl(hasName("A")).bind("id"),
- "template <typename ..., int ...,"
- " template <typename ..., bool ...> class ...> void A()"));
+ ASSERT_TRUE(
+ PrintedDeclCXX17Matches("template <typename ..., int ...,"
+ " template <typename ...> class ...> void A();",
+ functionTemplateDecl(hasName("A")).bind("id"),
+ "template <typename ..., int ...,"
+ " template <typename ...> class ...> void A()"));
}
TEST(DeclPrinter, TestNamedTemplateParametersPacks) {
ASSERT_TRUE(PrintedDeclCXX17Matches(
"template <typename ...T, int ...I,"
- " template <typename ...X, bool ...B> class ...Z> void A();",
+ " template <typename ...X> class ...Z> void A();",
functionTemplateDecl(hasName("A")).bind("id"),
"template <typename ...T, int ...I,"
- " template <typename ...X, bool ...B> class ...Z> void A()"));
+ " template <typename ...X> class ...Z> void A()"));
}
TEST(DeclPrinter, TestTemplateTemplateParameterWrittenWithTypename) {
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