Adding a test for Item_default_value in WHERE condition:

  WHERE DEFAULT(col)
It seems this was not covered yet.

mysql-test/r/default.result

@@ -220,3 +220,17 @@ NULL
 10
 drop table t1, t2;
 End of 5.0 tests.
+#
+# Start of 10.1 tests
+#
+CREATE TABLE t1 (a INT DEFAULT 100, b INT DEFAULT NULL);
+INSERT INTO t1 VALUES ();
+SELECT * FROM t1 WHERE DEFAULT(a);
+a	b
+100	NULL
+SELECT * FROM t1 WHERE DEFAULT(b);
+a	b
+DROP TABLE IF EXISTS t1;
+#
+# End of 10.1 tests
+#

mysql-test/t/default.test

@@ -166,3 +166,18 @@ drop table t1, t2;
 
 --echo End of 5.0 tests.
 
+--echo #
+--echo # Start of 10.1 tests
+--echo #
+
+# Using DEFAULT(col) in WHERE condition
+CREATE TABLE t1 (a INT DEFAULT 100, b INT DEFAULT NULL);
+INSERT INTO t1 VALUES ();
+SELECT * FROM t1 WHERE DEFAULT(a);
+SELECT * FROM t1 WHERE DEFAULT(b);
+DROP TABLE IF EXISTS t1;
+
+
+--echo #
+--echo # End of 10.1 tests
+--echo #