diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index fa150e3462fc..6506f288e059 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-04-23  Patrick Palka  <ppalka@redhat.com>
+
+	PR c++/94645
+	* pt.c (template_class_depth): Walk into the DECL_FRIEND_CONTEXT of a
+	friend declaration rather than into its CP_DECL_CONTEXT.
+
 2020-04-23 Iain Sandoe <iain@sandoe.co.uk>
 
 	PR c++/94288
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 2fe7b66707c6..66308a2d2958 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -390,7 +390,12 @@ template_class_depth (tree type)
 	++depth;
 
       if (DECL_P (type))
-	type = CP_DECL_CONTEXT (type);
+	{
+	  if (tree fctx = DECL_FRIEND_CONTEXT (type))
+	    type = fctx;
+	  else
+	    type = CP_DECL_CONTEXT (type);
+	}
       else if (LAMBDA_TYPE_P (type) && LAMBDA_TYPE_EXTRA_SCOPE (type))
 	type = LAMBDA_TYPE_EXTRA_SCOPE (type);
       else
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f9ab061922e5..e0df5bc0a99b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-23  Patrick Palka  <ppalka@redhat.com>
+
+	PR c++/94645
+	* g++.dg/cpp2a/concepts-lambda6.C: New test.
+
 2019-04-23  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* g++.dg/opt/store-merging-4.C: New test.
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C
new file mode 100644
index 000000000000..0b7c04562e9b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda6.C
@@ -0,0 +1,19 @@
+// PR c++/94645
+// { dg-do compile { target concepts } }
+
+struct unordered_map {
+  int cend() const noexcept;
+};
+
+template <typename a> concept HasMapInterface = requires(a t) { t.cend(); };
+
+template <typename Mapper> requires HasMapInterface<decltype(Mapper::map())>
+struct l {
+  friend void foo(l opt) { ([]() {})(); }
+};
+
+struct p {
+  static unordered_map map();
+};
+
+void g(l<p> *y) { foo(*y); }