1 files changed, 10 insertions, 8 deletions
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index e2dc703..3819f77 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1580,17 +1580,19 @@ Decl *TemplateDeclInstantiator::InstantiateTypeAliasTemplateDecl(
   if (!InstParams)
     return nullptr;
 
-  TypeAliasDecl *Pattern = D->getTemplatedDecl();
-  Sema::InstantiatingTemplate InstTemplate(
-      SemaRef, D->getBeginLoc(), D,
-      D->getTemplateDepth() >= TemplateArgs.getNumLevels()
-          ? ArrayRef<TemplateArgument>()
-          : (TemplateArgs.begin() + TemplateArgs.getNumLevels() - 1 -
-             D->getTemplateDepth())
-                ->Args);
+  // FIXME: This is a hack for instantiating lambdas in the pattern of the
+  // alias. We are not really instantiating the alias at its template level,
+  // that only happens in CheckTemplateId, this is only for outer templates
+  // which contain it. In getTemplateInstantiationArgs, the template arguments
+  // used here would be used for collating the template arguments needed to
+  // instantiate the lambda. Pass an empty argument list, so this workaround
+  // doesn't get confused if there is an outer alias being instantiated.
+  Sema::InstantiatingTemplate InstTemplate(SemaRef, D->getBeginLoc(), D,
+                                           ArrayRef<TemplateArgument>());
   if (InstTemplate.isInvalid())
     return nullptr;
 
+  TypeAliasDecl *Pattern = D->getTemplatedDecl();
   TypeAliasTemplateDecl *PrevAliasTemplate = nullptr;
   if (getPreviousDeclForInstantiation<TypedefNameDecl>(Pattern)) {
     DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());