diff --git a/gdk/gdkmemoryformat.c b/gdk/gdkmemoryformat.c
index c9fdc38192..5d17e84240 100644
--- a/gdk/gdkmemoryformat.c
+++ b/gdk/gdkmemoryformat.c
@@ -1479,6 +1479,7 @@ gdk_memory_depth_merge (GdkMemoryDepth depth1,
         else
           return GDK_MEMORY_FLOAT32;
 
+      case GDK_N_DEPTHS:
       default:
         g_assert_not_reached ();
         return GDK_MEMORY_U8;
@@ -1507,6 +1508,7 @@ gdk_memory_depth_get_format (GdkMemoryDepth depth)
         return GDK_MEMORY_R16G16B16A16_FLOAT_PREMULTIPLIED;
       case GDK_MEMORY_FLOAT32:
         return GDK_MEMORY_R32G32B32A32_FLOAT_PREMULTIPLIED;
+      case GDK_N_DEPTHS:
       default:
         g_return_val_if_reached (GDK_MEMORY_R8G8B8A8_PREMULTIPLIED);
     }
@@ -1534,6 +1536,7 @@ gdk_memory_depth_get_alpha_format (GdkMemoryDepth depth)
         return GDK_MEMORY_A16_FLOAT;
       case GDK_MEMORY_FLOAT32:
         return GDK_MEMORY_A32_FLOAT;
+      case GDK_N_DEPTHS:
       default:
         g_return_val_if_reached (GDK_MEMORY_A8);
     }
diff --git a/gdk/gdkmemoryformatprivate.h b/gdk/gdkmemoryformatprivate.h
index 878fd129e0..5e977f6a81 100644
--- a/gdk/gdkmemoryformatprivate.h
+++ b/gdk/gdkmemoryformatprivate.h
@@ -40,7 +40,9 @@ typedef enum {
   GDK_MEMORY_U8,
   GDK_MEMORY_U16,
   GDK_MEMORY_FLOAT16,
-  GDK_MEMORY_FLOAT32
+  GDK_MEMORY_FLOAT32,
+
+  GDK_N_DEPTHS
 } GdkMemoryDepth;
 
 gsize                   gdk_memory_format_alignment         (GdkMemoryFormat             format) G_GNUC_CONST;
diff --git a/gdk/gdkvulkancontext.c b/gdk/gdkvulkancontext.c
index fe78c8d5a0..035919b6e1 100644
--- a/gdk/gdkvulkancontext.c
+++ b/gdk/gdkvulkancontext.c
@@ -72,7 +72,7 @@ struct _GdkVulkanContextPrivate {
   struct {
     VkSurfaceFormatKHR vk_format;
     GdkMemoryFormat gdk_format;
-  } formats[4];
+  } formats[GDK_N_DEPTHS];
   GdkMemoryDepth current_depth;
 
   VkSwapchainKHR swapchain;
diff --git a/gsk/gskrendernodeparser.c b/gsk/gskrendernodeparser.c
index edb07f7f1f..204e51ebc9 100644
--- a/gsk/gskrendernodeparser.c
+++ b/gsk/gskrendernodeparser.c
@@ -3614,6 +3614,7 @@ append_texture_param (Printer    *p,
       g_string_append (p->str, "url(\"data:image/tiff;base64,\\\n");
       break;
 
+    case GDK_N_DEPTHS:
     default:
       g_assert_not_reached ();
     }