diff --git a/gio/gfilteroutputstream.c b/gio/gfilteroutputstream.c
index cb1602ef3..4fc82d45c 100644
--- a/gio/gfilteroutputstream.c
+++ b/gio/gfilteroutputstream.c
@@ -89,7 +89,7 @@ g_filter_output_stream_class_init (GFilterOutputStreamClass *klass)
   ostream_class->close_fn = g_filter_output_stream_close;
 
   /**
-   * GFilterOutputStream:close-base-stream:
+   * GFilterOutputStream:base-stream:
    *
    * The underlying base stream on which the I/O ops will be done.
    */
diff --git a/glib/gfileutils.c b/glib/gfileutils.c
index f40400ca5..25500cbf5 100644
--- a/glib/gfileutils.c
+++ b/glib/gfileutils.c
@@ -2991,6 +2991,7 @@ g_get_current_dir (void)
     {
       /* Fallback return value */
       g_assert (buffer_size >= 2);
+      g_assert (buffer != NULL);
       buffer[0] = G_DIR_SEPARATOR;
       buffer[1] = 0;
     }
diff --git a/glib/goption.c b/glib/goption.c
index 8ac283ce4..170b88dd2 100644
--- a/glib/goption.c
+++ b/glib/goption.c
@@ -2559,7 +2559,7 @@ g_option_context_get_description (GOptionContext *context)
 /**
  * g_option_context_parse_strv:
  * @context: a #GOptionContext
- * @arguments: (inout) (array null-terminated=1) (optional): a pointer
+ * @arguments: (inout) (array zero-terminated=1) (optional): a pointer
  *    to the command line arguments (which must be in UTF-8 on Windows).
  *    Starting with GLib 2.62, @arguments can be %NULL, which matches
  *    g_option_context_parse().
diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 9e9ee1e82..47bb9c66a 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -611,7 +611,7 @@
 
 /**
  * g_assert_no_error:
- * @err: (nullable) a `GError`
+ * @err: (nullable): a `GError`
  *
  * Debugging macro to check that a [struct@GLib.Error] is not set.
  *
diff --git a/glib/tests/error.c b/glib/tests/error.c
index 8dd40aa56..cdd6b1e3c 100644
--- a/glib/tests/error.c
+++ b/glib/tests/error.c
@@ -258,6 +258,8 @@ typedef struct
 static void
 test_error_private_init (TestErrorPrivate *priv)
 {
+  g_assert_nonnull (priv);
+
   priv->foo = 13;
   /* If that triggers, it's test bug.
    */
@@ -272,15 +274,20 @@ static void
 test_error_private_copy (const TestErrorPrivate *src_priv,
                          TestErrorPrivate       *dest_priv)
 {
+  g_assert_nonnull (src_priv);
+  g_assert_nonnull (dest_priv);
+
   dest_priv->foo = src_priv->foo;
   dest_priv->check = src_priv->check;
 
+  g_assert_nonnull (dest_priv->check);
   dest_priv->check->copy_called++;
 }
 
 static void
 test_error_private_clear (TestErrorPrivate *priv)
 {
+  g_assert_nonnull (priv->check);
   priv->check->free_called++;
 }
 
@@ -291,6 +298,7 @@ fill_test_error (GError *error, TestErrorCheck *check)
 {
   TestErrorPrivate *test_error = test_error_get_private (error);
 
+  g_assert_nonnull (test_error);
   test_error->check = check;
 
   return test_error;
@@ -326,6 +334,7 @@ test_extended (void)
   g_assert_cmpstr (error->message, ==, copy_error->message);
 
   copy_test_priv = test_error_get_private (copy_error);
+  g_assert_nonnull (copy_test_priv);
   g_assert_cmpint (test_priv->foo, ==, copy_test_priv->foo);
 
   g_error_free (error);
diff --git a/glib/tests/mutex.c b/glib/tests/mutex.c
index bd484c59e..5a089a099 100644
--- a/glib/tests/mutex.c
+++ b/glib/tests/mutex.c
@@ -246,7 +246,7 @@ static void
 test_mutex_perf (gconstpointer data)
 {
   const guint n_threads = GPOINTER_TO_UINT (data);
-  GThread *threads[THREADS];
+  GThread *threads[THREADS] = { NULL, };
   gint64 start_time;
   gdouble rate;
   gint x = -1;