Apply clang fix for assertion failure compiling multimedia/minitube

Merge commit 79f9cfbc21e0 from llvm git (by Yaxun (Sam) Liu):

  Do not merge LocalInstantiationScope for template specialization

  A lambda in a function template may be recursively instantiated. The recursive
  lambda will cause a lambda function instantiated multiple times, one inside another.
  The inner LocalInstantiationScope should not be marked as MergeWithParentScope
  since it already has references to locals properly substituted, otherwise it causes
  assertion due to the check for duplicate locals in merged LocalInstantiationScope.

  Reviewed by: Richard Smith

  Differential Revision: https://reviews.llvm.org/D98068

Reported by:	yuri
PR:		257978

(cherry picked from commit efa485d5c390b745f53761da9159721243c48b7b)

1 files changed, 5 insertions, 2 deletions

diff --git a/contrib/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/contrib/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index f801e79c8902..f36fa8d11b3b 100644
--- a/contrib/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/contrib/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -4658,10 +4658,13 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
   // Introduce a new scope where local variable instantiations will be
   // recorded, unless we're actually a member function within a local
   // class, in which case we need to merge our results with the parent
-  // scope (of the enclosing function).
+  // scope (of the enclosing function). The exception is instantiating
+  // a function template specialization, since the template to be
+  // instantiated already has references to locals properly substituted.
   bool MergeWithParentScope = false;
   if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
-    MergeWithParentScope = Rec->isLocalClass();
+    MergeWithParentScope =
+        Rec->isLocalClass() && !Function->isFunctionTemplateSpecialization();
 
   LocalInstantiationScope Scope(*this, MergeWithParentScope);