diff --git a/mysql-test/r/parser.result b/mysql-test/r/parser.result
index 499f37e6dfb..8ebb45b927b 100644
--- a/mysql-test/r/parser.result
+++ b/mysql-test/r/parser.result
@@ -1239,3 +1239,44 @@ a
 20
 1
 DROP TABLE t1;
+#
+# MDEV-10779 Failing assertion lex->proc_list.elements == 0 or syntax error on PROCEDURE ANALYSE in UNION
+#
+CREATE TABLE t1 (i INT);
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10));
+ERROR HY000: Incorrect usage of UNION and SELECT ... PROCEDURE ANALYSE()
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10);
+ERROR HY000: Incorrect usage of UNION and SELECT ... PROCEDURE ANALYSE()
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+(SELECT 1);
+ERROR HY000: Incorrect usage of UNION and SELECT ... PROCEDURE ANALYSE()
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+SELECT 1;
+ERROR HY000: Incorrect usage of UNION and SELECT ... PROCEDURE ANALYSE()
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10));
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'UNION
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))' at line 2
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10);
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'UNION
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)' at line 2
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+(SELECT 1);
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'UNION
+(SELECT 1)' at line 2
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+SELECT 1;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'UNION
+SELECT 1' at line 2
+DROP TABLE t1;
diff --git a/mysql-test/t/parser.test b/mysql-test/t/parser.test
index 90b0fb11648..5970b564c85 100644
--- a/mysql-test/t/parser.test
+++ b/mysql-test/t/parser.test
@@ -1263,3 +1263,51 @@ SELECT a FROM t1 GROUP BY a WITH ROLLUP UNION SELECT 1 ORDER BY a LIMIT 1;
 SELECT 1 AS a UNION (SELECT a FROM t1 GROUP BY a WITH ROLLUP LIMIT 2);
 (SELECT a FROM t1 GROUP BY a WITH ROLLUP LIMIT 2) UNION SELECT 1;
 DROP TABLE t1;
+
+
+--echo #
+--echo # MDEV-10779 Failing assertion lex->proc_list.elements == 0 or syntax error on PROCEDURE ANALYSE in UNION
+--echo #
+
+CREATE TABLE t1 (i INT);
+--error ER_WRONG_USAGE
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10));
+
+--error ER_WRONG_USAGE
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10);
+
+--error ER_WRONG_USAGE
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+(SELECT 1);
+
+--error ER_WRONG_USAGE
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10))
+UNION
+SELECT 1;
+
+--error ER_PARSE_ERROR
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+(SELECT * FROM t1 PROCEDURE ANALYSE(10, 10));
+
+--error ER_PARSE_ERROR
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10);
+
+--error ER_PARSE_ERROR
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+(SELECT 1);
+
+--error ER_PARSE_ERROR
+SELECT * FROM t1 PROCEDURE ANALYSE(10, 10)
+UNION
+SELECT 1;
+
+DROP TABLE t1;
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 6baff31537a..266c6119f13 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -7485,8 +7485,22 @@ mysql_new_select(LEX *lex, bool move_down)
       DBUG_RETURN(TRUE);
     }
 
-    // SELECT 1 FROM t1 PROCEDURE ANALYSE() UNION ...  --    not possible
-    DBUG_ASSERT(lex->proc_list.elements == 0);
+    /*
+      This type of query is not possible in the grammar:
+        SELECT 1 FROM t1 PROCEDURE ANALYSE() UNION ... ;
+
+      But this type of query is still possible:
+        (SELECT 1 FROM t1 PROCEDURE ANALYSE()) UNION ... ;
+      and it's not easy to disallow this grammatically,
+      because there can be any parenthesis nest level:
+        (((SELECT 1 FROM t1 PROCEDURE ANALYSE()))) UNION ... ;
+    */
+    if (lex->proc_list.elements!=0)
+    {
+      my_error(ER_WRONG_USAGE, MYF(0), "UNION",
+               "SELECT ... PROCEDURE ANALYSE()");
+      DBUG_RETURN(TRUE);
+    }
     // SELECT 1 FROM t1 ORDER BY 1 UNION SELECT 1 FROM t1 -- not possible
     DBUG_ASSERT(!lex->current_select->order_list.first ||
                 lex->current_select->braces);