[c++20] Implement P0428R2 - Familiar template syntax for generic lambdas

Differential Revision: https://reviews.llvm.org/D36527

llvm-svn: 359967

1 files changed, 18 insertions, 1 deletions

diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 9946d16a858..b9ecdc65720 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -1421,13 +1421,30 @@ void CXXRecordDecl::getCaptureFields(
 
 TemplateParameterList *
 CXXRecordDecl::getGenericLambdaTemplateParameterList() const {
-  if (!isLambda()) return nullptr;
+  if (!isGenericLambda()) return nullptr;
   CXXMethodDecl *CallOp = getLambdaCallOperator();
   if (FunctionTemplateDecl *Tmpl = CallOp->getDescribedFunctionTemplate())
     return Tmpl->getTemplateParameters();
   return nullptr;
 }
 
+ArrayRef<NamedDecl *>
+CXXRecordDecl::getLambdaExplicitTemplateParameters() const {
+  TemplateParameterList *List = getGenericLambdaTemplateParameterList();
+  if (!List)
+    return {};
+
+  assert(std::is_partitioned(List->begin(), List->end(),
+                             [](const NamedDecl *D) { return !D->isImplicit(); })
+         && "Explicit template params should be ordered before implicit ones");
+
+  const auto ExplicitEnd = std::lower_bound(List->begin(), List->end(), false,
+                                            [](const NamedDecl *D, bool) {
+    return !D->isImplicit();
+  });
+  return llvm::makeArrayRef(List->begin(), ExplicitEnd);
+}
+
 Decl *CXXRecordDecl::getLambdaContextDecl() const {
   assert(isLambda() && "Not a lambda closure type!");
   ExternalASTSource *Source = getParentASTContext().getExternalSource();