fix

Author: Backl1ght

clang/docs/ReleaseNotes.rst

@@ -1083,6 +1083,8 @@ Bug Fixes to C++ Support
 - Clang now diagnoses explicit object parameters in member pointers and other contexts where they should not appear.
   Fixes (#GH85992).
 - Fixed a crash-on-invalid bug involving extraneous template parameter with concept substitution. (#GH73885)
+- Fixed an assertion failure about a constraint of a friend function template references to a value with greater
+  template depth than the friend function template. (#GH98258)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaTemplate.cpp

@@ -1691,10 +1691,7 @@ class ConstraintRefersToContainingTemplateChecker
   using inherited::TransformTemplateTypeParmType;
   QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                          TemplateTypeParmTypeLoc TL, bool) {
-    assert(TL.getDecl()->getDepth() <= TemplateDepth &&
-           "Nothing should reference a value below the actual template depth, "
-           "depth is likely wrong");
-    if (TL.getDecl()->getDepth() != TemplateDepth)
+    if (TL.getDecl()->getDepth() < TemplateDepth)
       Result = true;
     return inherited::TransformTemplateTypeParmType(
         TLB, TL,

clang/test/SemaTemplate/concepts-friends.cpp

@@ -504,3 +504,19 @@ template struct Z<int>;
 Y y(1);
 
 }
+
+namespace GH98258 {
+
+struct S {
+  template <typename U>
+  friend void f() requires requires { []<typename V>(V){}; } {
+    return;
+  }
+
+  template <typename U>
+  friend void f2() requires requires { [](auto){}; } {
+    return;
+  }
+};
+
+}