From 9fb69cd3b8aea83f982d580be44b0b133d615335 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Wed, 4 Sep 2019 22:14:50 +0000
Subject: [PATCH] For PR43213, track whether template parameters are implicit
 through template instantiation so we know whether to mangle them in
 lambda-expressions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@370991 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaTemplateInstantiateDecl.cpp                   | 3 +++
 test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 6e4f9b9947..5ef16b4a37 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2337,6 +2337,7 @@ Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
       D->getDepth() - TemplateArgs.getNumSubstitutedLevels(), D->getIndex(),
       D->getIdentifier(), D->wasDeclaredWithTypename(), D->isParameterPack());
   Inst->setAccess(AS_public);
+  Inst->setImplicit(D->isImplicit());
 
   if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {
     TypeSourceInfo *InstantiatedDefaultArg =
@@ -2483,6 +2484,7 @@ Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
         D->getPosition(), D->getIdentifier(), T, D->isParameterPack(), DI);
 
   Param->setAccess(AS_public);
+  Param->setImplicit(D->isImplicit());
   if (Invalid)
     Param->setInvalidDecl();
 
@@ -2626,6 +2628,7 @@ TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
                               D->getDefaultArgument().getTemplateNameLoc()));
   }
   Param->setAccess(AS_public);
+  Param->setImplicit(D->isImplicit());
 
   // Introduce this template parameter's instantiation into the instantiation
   // scope.
diff --git a/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp b/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp
index 3bec64156a..b88b0d56fd 100644
--- a/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp
+++ b/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp
@@ -32,3 +32,10 @@ inline void inline_func() {
 void call_inline_func() {
   inline_func();
 }
+
+template<typename> void f() {
+  // CHECK: define linkonce_odr {{.*}} @_ZZ1fIiEvvENKUlT_E_clIiEEDaS0_(
+  auto x = [](auto){};
+  x(0);
+}
+void use_f() { f<int>(); }
-- 
2.40.0