PR for llvm#79568 (llvm#80120)

Backporting llvm#79568 to clang 18.

Author: zyn0217

clang/docs/ReleaseNotes.rst

@@ -1125,6 +1125,11 @@ Bug Fixes to C++ Support
 - Fix handling of ``_`` as the name of a lambda's init capture variable. (#GH107024)
 
 
+
+- Fixed a bug where variables referenced by requires-clauses inside
+  nested generic lambdas were not properly injected into the constraint scope.
+  (`#73418 <https://github.com/llvm/llvm-project/issues/73418>`_)
+
 - Fix incorrect code generation caused by the object argument of ``static operator()`` and ``static operator[]`` calls not being evaluated.
   Fixes (`#67976 <https://github.com/llvm/llvm-project/issues/67976>`_)