diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 779ccf5f1e888..576eb326e6529 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -1251,6 +1251,10 @@ Sema::CXXThisScopeRAII::CXXThisScopeRAII(Sema &S,
   else
     Record = cast<CXXRecordDecl>(ContextDecl);
 
+  // 'this' never refers to the lambda class itself.
+  if (Record->isLambda())
+    return;
+
   QualType T = S.Context.getCanonicalTagType(Record);
   T = S.getASTContext().getQualifiedType(T, CXXThisTypeQuals);
 
diff --git a/clang/test/SemaTemplate/GH161657.cpp b/clang/test/SemaTemplate/GH161657.cpp
new file mode 100644
index 0000000000000..6ec793115db12
--- /dev/null
+++ b/clang/test/SemaTemplate/GH161657.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++20 -ffp-exception-behavior=strict -verify %s
+// expected-no-diagnostics
+
+template <class T> struct S {
+  template <class U> using type1 = decltype([] { return U{}; });
+};
+
+void foo() {
+  using T1 = S<int>::type1<int>;
+  int x = T1()();
+}