I have pulled latest sources from git and tried to create multi-level partition, getting a server crash, below are steps to reproduce. please check if it is reproducible in your machine also.
postgres=# CREATE TABLE test_ml (a int, b int, c varchar) PARTITION BY RANGE(a); CREATE TABLE postgres=# CREATE TABLE test_ml_p1 PARTITION OF test_ml FOR VALUES FROM (0) TO (250) PARTITION BY RANGE (b); CREATE TABLE postgres=# CREATE TABLE test_ml_p1_p1 PARTITION OF test_ml_p1 FOR VALUES FROM (0) TO (100); CREATE TABLE postgres=# CREATE TABLE test_ml_p1_p2 PARTITION OF test_ml_p1 FOR VALUES FROM (100) TO (250); CREATE TABLE postgres=# CREATE TABLE test_ml_p2 PARTITION OF test_ml FOR VALUES FROM (250) TO (500) PARTITION BY RANGE (c); CREATE TABLE postgres=# CREATE TABLE test_ml_p2_p1 PARTITION OF test_ml_p2 FOR VALUES FROM ('0250') TO ('0400'); CREATE TABLE postgres=# CREATE TABLE test_ml_p2_p2 PARTITION OF test_ml_p2 FOR VALUES FROM ('0400') TO ('0500'); CREATE TABLE postgres=# CREATE TABLE test_ml_p3 PARTITION OF test_ml FOR VALUES FROM (500) TO (600) PARTITION BY RANGE ((b + a)); CREATE TABLE postgres=# CREATE TABLE test_ml_p3_p1 PARTITION OF test_ml_p3 FOR VALUES FROM (1000) TO (1100); CREATE TABLE postgres=# CREATE TABLE test_ml_p3_p2 PARTITION OF test_ml_p3 FOR VALUES FROM (1100) TO (1200); CREATE TABLE postgres=# INSERT INTO test_ml SELECT i, i, to_char(i, 'FM0000') FROM generate_series(0, 599, 2) i; server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. The connection to the server was lost. Attempting reset: Failed.