[clang] 06aadbe - Revert "[clang] Implement CWG2398 provisional TTP matching to class templates" (#93258)
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Thu May 23 17:33:38 PDT 2024
Author: Matheus Izvekov
Date: 2024-05-23T21:33:35-03:00
New Revision: 06aadbeb2538c3e28cca7c82db102dffc7bdc269
URL: https://github.com/llvm/llvm-project/commit/06aadbeb2538c3e28cca7c82db102dffc7bdc269
DIFF: https://github.com/llvm/llvm-project/commit/06aadbeb2538c3e28cca7c82db102dffc7bdc269.diff
LOG: Revert "[clang] Implement CWG2398 provisional TTP matching to class templates" (#93258)
Reverts llvm/llvm-project#92855
This is causing issues, there are still being reduced, but does look
like a problem.
See PR for user reports.
Added:
Modified:
clang/lib/Sema/SemaTemplate.cpp
clang/lib/Sema/SemaTemplateDeduction.cpp
clang/test/CXX/temp/temp.decls/temp.alias/p2.cpp
clang/test/SemaTemplate/cwg2398.cpp
Removed:
################################################################################
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 268f079980a6c..39e9dbed0c3e0 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1807,8 +1807,6 @@ static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
// Returns the template parameter list with all default template argument
// information.
static TemplateParameterList *GetTemplateParameterList(TemplateDecl *TD) {
- if (TD->isImplicit())
- return TD->getTemplateParameters();
// Make sure we get the template parameter list from the most
// recent declaration, since that is the only one that is guaranteed to
// have all the default template argument information.
@@ -1829,8 +1827,7 @@ static TemplateParameterList *GetTemplateParameterList(TemplateDecl *TD) {
// template <class = void> friend struct C;
// };
// template struct S<int>;
- while ((D->isImplicit() ||
- D->getFriendObjectKind() != Decl::FriendObjectKind::FOK_None) &&
+ while (D->getFriendObjectKind() != Decl::FriendObjectKind::FOK_None &&
D->getPreviousDecl())
D = D->getPreviousDecl();
return cast<TemplateDecl>(D)->getTemplateParameters();
diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index 08a69d3cb2589..f9ec34163e656 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -527,8 +527,8 @@ static NamedDecl *getTemplateParameterWithDefault(Sema &S, NamedDecl *A,
R->setDefaultArgument(
S.Context,
S.getTrivialTemplateArgumentLoc(Default, QualType(), SourceLocation()));
- if (T->hasTypeConstraint()) {
- auto *C = T->getTypeConstraint();
+ if (R->hasTypeConstraint()) {
+ auto *C = R->getTypeConstraint();
R->setTypeConstraint(C->getConceptReference(),
C->getImmediatelyDeclaredConstraint());
}
@@ -583,53 +583,37 @@ DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
return TemplateDeductionResult::Success;
auto NewDeduced = DeducedTemplateArgument(Arg);
- // Provisional resolution for CWG2398: If Arg names a template
- // specialization, then we deduce a synthesized template template parameter
- // based on A, but using the TS's arguments as defaults.
- if (DefaultArguments.size() != 0) {
+ // Provisional resolution for CWG2398: If Arg is also a template template
+ // param, and it names a template specialization, then we deduce a
+ // synthesized template template parameter based on A, but using the TS's
+ // arguments as defaults.
+ if (auto *TempArg = dyn_cast_or_null<TemplateTemplateParmDecl>(
+ Arg.getAsTemplateDecl())) {
assert(Arg.getKind() == TemplateName::Template);
- TemplateDecl *TempArg = Arg.getAsTemplateDecl();
+ assert(!TempArg->isExpandedParameterPack());
+
TemplateParameterList *As = TempArg->getTemplateParameters();
- assert(DefaultArguments.size() <= As->size());
-
- SmallVector<NamedDecl *, 4> Params(As->size());
- for (unsigned I = 0; I < DefaultArguments.size(); ++I)
- Params[I] = getTemplateParameterWithDefault(S, As->getParam(I),
- DefaultArguments[I]);
- for (unsigned I = DefaultArguments.size(); I < As->size(); ++I)
- Params[I] = As->getParam(I);
- // FIXME: We could unique these, and also the parameters, but we don't
- // expect programs to contain a large enough amount of these deductions
- // for that to be worthwhile.
- auto *TPL = TemplateParameterList::Create(
- S.Context, SourceLocation(), SourceLocation(), Params,
- SourceLocation(), As->getRequiresClause());
-
- TemplateDecl *TD;
- switch (TempArg->getKind()) {
- case Decl::TemplateTemplateParm: {
- auto *A = cast<TemplateTemplateParmDecl>(TempArg);
- assert(!A->isExpandedParameterPack());
- TD = TemplateTemplateParmDecl::Create(
- S.Context, A->getDeclContext(), SourceLocation(), A->getDepth(),
- A->getPosition(), A->isParameterPack(), A->getIdentifier(),
- A->wasDeclaredWithTypename(), TPL);
- break;
- }
- case Decl::ClassTemplate: {
- auto *A = cast<ClassTemplateDecl>(TempArg);
- auto *CT = ClassTemplateDecl::Create(S.Context, A->getDeclContext(),
- SourceLocation(), A->getDeclName(),
- TPL, A->getTemplatedDecl());
- CT->setPreviousDecl(A);
- TD = CT;
- break;
- }
- default:
- llvm_unreachable("Unexpected Template Kind");
+ if (DefaultArguments.size() != 0) {
+ assert(DefaultArguments.size() <= As->size());
+ SmallVector<NamedDecl *, 4> Params(As->size());
+ for (unsigned I = 0; I < DefaultArguments.size(); ++I)
+ Params[I] = getTemplateParameterWithDefault(S, As->getParam(I),
+ DefaultArguments[I]);
+ for (unsigned I = DefaultArguments.size(); I < As->size(); ++I)
+ Params[I] = As->getParam(I);
+ // FIXME: We could unique these, and also the parameters, but we don't
+ // expect programs to contain a large enough amount of these deductions
+ // for that to be worthwhile.
+ auto *TPL = TemplateParameterList::Create(
+ S.Context, SourceLocation(), SourceLocation(), Params,
+ SourceLocation(), As->getRequiresClause());
+ NewDeduced = DeducedTemplateArgument(
+ TemplateName(TemplateTemplateParmDecl::Create(
+ S.Context, TempArg->getDeclContext(), SourceLocation(),
+ TempArg->getDepth(), TempArg->getPosition(),
+ TempArg->isParameterPack(), TempArg->getIdentifier(),
+ TempArg->wasDeclaredWithTypename(), TPL)));
}
- TD->setImplicit(true);
- NewDeduced = DeducedTemplateArgument(TemplateName(TD));
}
DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
diff --git a/clang/test/CXX/temp/temp.decls/temp.alias/p2.cpp b/clang/test/CXX/temp/temp.decls/temp.alias/p2.cpp
index bc39431253880..a5b39fe5c51f7 100644
--- a/clang/test/CXX/temp/temp.decls/temp.alias/p2.cpp
+++ b/clang/test/CXX/temp/temp.decls/temp.alias/p2.cpp
@@ -28,14 +28,13 @@ namespace StdExample {
{ /* ... */ }
template<template<class> class TT>
- void f(TT<int>);
+ void f(TT<int>); // expected-note {{candidate template ignored}}
template<template<class,class> class TT>
void g(TT<int, Alloc<int>>);
int h() {
- f(v); // OK: TT = vector, Alloc<int> is used as the default argument for the
- // second parameter.
+ f(v); // expected-error {{no matching function for call to 'f'}}
g(v); // OK: TT = vector
}
diff --git a/clang/test/SemaTemplate/cwg2398.cpp b/clang/test/SemaTemplate/cwg2398.cpp
index 4cc946735a1e2..e3b5e575374d3 100644
--- a/clang/test/SemaTemplate/cwg2398.cpp
+++ b/clang/test/SemaTemplate/cwg2398.cpp
@@ -65,10 +65,13 @@ namespace class_template {
template <class T3> struct B;
template <template <class T4> class TT1, class T5> struct B<TT1<T5>>;
+ // new-note at -1 {{partial specialization matches}}
template <class T6, class T7> struct B<A<T6, T7>> {};
+ // new-note at -1 {{partial specialization matches}}
template struct B<A<int>>;
+ // new-error at -1 {{ambiguous partial specialization}}
} // namespace class_template
namespace type_pack1 {
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