diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 4eefb2d3584..877e442bc41 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -10737,18 +10737,24 @@ trees_out::get_merge_kind (tree decl, depset *dep)
 	       g++.dg/modules/lambda-6_a.C.  */
 	    if (DECL_IMPLICIT_TYPEDEF_P (STRIP_TEMPLATE (decl))
 		&& LAMBDA_TYPE_P (TREE_TYPE (decl)))
-	      if (tree scope = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl)))
-		{
-		  /* Lambdas attached to fields are keyed to its class.  */
-		  if (TREE_CODE (scope) == FIELD_DECL)
-		    scope = TYPE_NAME (DECL_CONTEXT (scope));
-		  if (DECL_LANG_SPECIFIC (scope)
-		      && DECL_MODULE_KEYED_DECLS_P (scope))
-		    {
-		      mk = MK_keyed;
-		      break;
-		    }
-		}
+	      {
+		if (tree scope = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl)))
+		  {
+		    /* Lambdas attached to fields are keyed to its class.  */
+		    if (TREE_CODE (scope) == FIELD_DECL)
+		      scope = TYPE_NAME (DECL_CONTEXT (scope));
+		    if (DECL_LANG_SPECIFIC (scope)
+			&& DECL_MODULE_KEYED_DECLS_P (scope))
+		      {
+			mk = MK_keyed;
+			break;
+		      }
+		  }
+		/* Lambdas without extra mangling scope are unique to the TU,
+		   and cannot be merged; make them unique.  */
+		mk = MK_unique;
+		break;
+	      }
 
 	    if (TREE_CODE (decl) == TEMPLATE_DECL
 		&& DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (decl))
diff --git a/gcc/testsuite/g++.dg/modules/lambda-8.h b/gcc/testsuite/g++.dg/modules/lambda-8.h
new file mode 100644
index 00000000000..0c66f053b20
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/lambda-8.h
@@ -0,0 +1,7 @@
+template <typename> struct S {
+  template <typename> static constexpr auto x = []{};
+  template <typename> using t = decltype([]{});
+};
+
+inline auto x = S<int>::x<int>;
+using t = S<int>::t<int>;
diff --git a/gcc/testsuite/g++.dg/modules/lambda-8_a.H b/gcc/testsuite/g++.dg/modules/lambda-8_a.H
new file mode 100644
index 00000000000..d20958ee140
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/lambda-8_a.H
@@ -0,0 +1,5 @@
+// PR c++/116568
+// { dg-additional-options "-fmodules-ts -std=c++20" }
+// { dg-module-cmi {} }
+
+#include "lambda-8.h"
diff --git a/gcc/testsuite/g++.dg/modules/lambda-8_b.C b/gcc/testsuite/g++.dg/modules/lambda-8_b.C
new file mode 100644
index 00000000000..05ea4afd8c1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/lambda-8_b.C
@@ -0,0 +1,5 @@
+// PR c++/116568
+// { dg-additional-options "-fmodules-ts -std=c++20" }
+
+#include "lambda-8.h"
+import "lambda-8_a.H";