diff --git a/interpreter/llvm-project/clang/lib/AST/NestedNameSpecifier.cpp b/interpreter/llvm-project/clang/lib/AST/NestedNameSpecifier.cpp
index 36f2c47b30005..01adf429f2f26 100644
--- a/interpreter/llvm-project/clang/lib/AST/NestedNameSpecifier.cpp
+++ b/interpreter/llvm-project/clang/lib/AST/NestedNameSpecifier.cpp
@@ -285,13 +285,16 @@ void NestedNameSpecifier::print(raw_ostream &OS, const PrintingPolicy &Policy,
   case TypeSpec: {
     const auto *Record =
             dyn_cast_or_null<ClassTemplateSpecializationDecl>(getAsRecordDecl());
-    if (ResolveTemplateArguments && Record) {
+    const TemplateParameterList *TPL = nullptr;
+    if (Record) {
+      TPL = Record->getSpecializedTemplate()->getTemplateParameters();
+      if (ResolveTemplateArguments) {
         // Print the type trait with resolved template parameters.
         Record->printName(OS, Policy);
-        printTemplateArgumentList(
-            OS, Record->getTemplateArgs().asArray(), Policy,
-            Record->getSpecializedTemplate()->getTemplateParameters());
+        printTemplateArgumentList(OS, Record->getTemplateArgs().asArray(),
+                                  Policy, TPL);
         break;
+      }
     }
     const Type *T = getAsType();
 
@@ -315,8 +318,8 @@ void NestedNameSpecifier::print(raw_ostream &OS, const PrintingPolicy &Policy,
                                         TemplateName::Qualified::None);
 
       // Print the template argument list.
-      printTemplateArgumentList(OS, SpecType->template_arguments(),
-                                InnerPolicy);
+      printTemplateArgumentList(OS, SpecType->template_arguments(), InnerPolicy,
+                                TPL);
     } else if (const auto *DepSpecType =
                    dyn_cast<DependentTemplateSpecializationType>(T)) {
       // Print the template name without its corresponding
@@ -324,7 +327,7 @@ void NestedNameSpecifier::print(raw_ostream &OS, const PrintingPolicy &Policy,
       OS << DepSpecType->getIdentifier()->getName();
       // Print the template argument list.
       printTemplateArgumentList(OS, DepSpecType->template_arguments(),
-                                InnerPolicy);
+                                InnerPolicy, TPL);
     } else {
       // Print the type normally
       QualType(T, 0).print(OS, InnerPolicy);
diff --git a/interpreter/llvm-project/llvm-project.tag b/interpreter/llvm-project/llvm-project.tag
index 5233b016951cc..be7c2e0f4ec51 100644
--- a/interpreter/llvm-project/llvm-project.tag
+++ b/interpreter/llvm-project/llvm-project.tag
@@ -1 +1 @@
-ROOT-llvm18-20250407-01
+ROOT-llvm18-20250506-01
diff --git a/roottest/root/meta/naming/CMakeLists.txt b/roottest/root/meta/naming/CMakeLists.txt
index 88d8058a7a0ed..b1045cd9fcb50 100644
--- a/roottest/root/meta/naming/CMakeLists.txt
+++ b/roottest/root/meta/naming/CMakeLists.txt
@@ -4,3 +4,5 @@ ROOTTEST_ADD_AUTOMACROS(DEPENDS namingMatches.cxx
 ROOTTEST_ADD_TEST(execCheckNaming
                   MACRO execCheckNaming.C
                   OUTREF execCheckNaming${ref_suffix})
+
+ROOTTEST_ADD_TESTDIRS()
diff --git a/roottest/root/meta/naming/issue-18363/CMakeLists.txt b/roottest/root/meta/naming/issue-18363/CMakeLists.txt
new file mode 100644
index 0000000000000..e95fdbc1dcb2a
--- /dev/null
+++ b/roottest/root/meta/naming/issue-18363/CMakeLists.txt
@@ -0,0 +1,6 @@
+ROOTTEST_GENERATE_REFLEX_DICTIONARY(templateDict Objects.h SELECTION selection.xml FIXTURES_SETUP template_lib)
+
+ROOTTEST_ADD_TEST(templateName
+                  MACRO templateNameTest.C
+                  OUTREF templateNameTest.ref
+		  FIXTURES_REQUIRED template_lib)
diff --git a/roottest/root/meta/naming/issue-18363/Objects.h b/roottest/root/meta/naming/issue-18363/Objects.h
new file mode 100644
index 0000000000000..ac9896d2f5cd9
--- /dev/null
+++ b/roottest/root/meta/naming/issue-18363/Objects.h
@@ -0,0 +1,9 @@
+#ifndef Objects_18363_hxx
+#define Objects_18363_hxx
+
+template <unsigned I>
+struct PFRecHitSoALayout {
+   struct View {};
+};
+
+#endif
diff --git a/roottest/root/meta/naming/issue-18363/selection.xml b/roottest/root/meta/naming/issue-18363/selection.xml
new file mode 100644
index 0000000000000..00d779217a6b0
--- /dev/null
+++ b/roottest/root/meta/naming/issue-18363/selection.xml
@@ -0,0 +1,4 @@
+<lcgdict>
+ <class name="PFRecHitSoALayout<128>"/>
+ <class name="PFRecHitSoALayout<128>::View"/>
+</lcgdict>
diff --git a/roottest/root/meta/naming/issue-18363/templateNameTest.C b/roottest/root/meta/naming/issue-18363/templateNameTest.C
new file mode 100644
index 0000000000000..4d413c537b22f
--- /dev/null
+++ b/roottest/root/meta/naming/issue-18363/templateNameTest.C
@@ -0,0 +1,26 @@
+{
+   TFile pcmfile("templateDict_rdict.pcm");
+   if (pcmfile.IsZombie()) {
+      std::cerr << "Error: Failed to open roottest/root pcm file: " << pcmfile.GetName() << '\n';
+      return 1;
+   }
+   TObjArray *protoArray = pcmfile.Get<TObjArray>("__ProtoClasses");
+   if (!protoArray) {
+      std::cerr << "Error: Failed to retrieve __ProtoClasses\n";
+      return 2;
+   }
+   protoArray->Print();
+
+   const char *classname = "PFRecHitSoALayout<128>::View";
+   auto cl = TClass::GetClass(classname);
+   if (!cl) {
+      std::cerr << "Error: Could not get the TClass for " << classname << "\n";
+      return 3;
+   }
+   if (!cl->IsLoaded()) {
+      std::cerr << "Error: The TClass is not loaded for " << classname << "\n";
+      return 4;
+   }
+
+   return 0;
+}
diff --git a/roottest/root/meta/naming/issue-18363/templateNameTest.ref b/roottest/root/meta/naming/issue-18363/templateNameTest.ref
new file mode 100644
index 0000000000000..d9733f30a26d7
--- /dev/null
+++ b/roottest/root/meta/naming/issue-18363/templateNameTest.ref
@@ -0,0 +1,5 @@
+
+Processing templateNameTest.C...
+Collection name='TObjArray', class='TObjArray', size=16
+ OBJ: TProtoClass	PFRecHitSoALayout<128>	
+ OBJ: TProtoClass	PFRecHitSoALayout<128>::View