[sqlsmith] Segfault in expand_tuple

Hi,

the following query triggers a segfault for me when run against the
regression database.  Testing was done with master at 039eb6e92f.
Backtrace below.

regards,
Andreas

select
  case when pg_catalog.lastval() < pg_catalog.pg_stat_get_bgwriter_maxwritten_clean() then case when
pg_catalog.circle_sub_pt(
      cast(cast(null as circle) as circle),
      cast((select location from public.emp limit 1 offset 13)
         as point)) ~ cast(nullif(case when cast(null as box) &> (select boxcol from public.brintest limit 1 offset 2)
         then (select f1 from public.circle_tbl limit 1 offset 4)
           else (select f1 from public.circle_tbl limit 1 offset 4)
           end,
      case when (select pg_catalog.max(class) from public.f_star)
         ~~ ref_0.c then cast(null as circle) else cast(null as circle) end
        ) as circle) then ref_0.a else ref_0.a end
       else case when pg_catalog.circle_sub_pt(
      cast(cast(null as circle) as circle),
      cast((select location from public.emp limit 1 offset 13)
         as point)) ~ cast(nullif(case when cast(null as box) &> (select boxcol from public.brintest limit 1 offset 2)
         then (select f1 from public.circle_tbl limit 1 offset 4)
           else (select f1 from public.circle_tbl limit 1 offset 4)
           end,
      case when (select pg_catalog.max(class) from public.f_star)
         ~~ ref_0.c then cast(null as circle) else cast(null as circle) end
        ) as circle) then ref_0.a else ref_0.a end
       end as c0,
  case when (select intervalcol from public.brintest limit 1 offset 1)
     >= cast(null as "interval") then case when ((select pg_catalog.max(roomno) from public.room)
         !~~ ref_0.c)
    and (cast(null as xid) <> 100) then ref_0.b else ref_0.b end
       else case when ((select pg_catalog.max(roomno) from public.room)
         !~~ ref_0.c)
    and (cast(null as xid) <> 100) then ref_0.b else ref_0.b end
       end as c1,
  ref_0.a as c2,
  (select a from public.idxpart1 limit 1 offset 5) as c3,
  ref_0.b as c4,
    pg_catalog.stddev(
      cast((select pg_catalog.sum(float4col) from public.brintest)
     as float4)) over (partition by ref_0.a,ref_0.b,ref_0.c order by ref_0.b) as c5,
  cast(nullif(ref_0.b, ref_0.a) as int4) as c6, ref_0.b as c7, ref_0.c as c8
from
  public.mlparted3 as ref_0
where true;

Core was generated by `postgres: smith regression [local] SELECT  '.
Program terminated with signal SIGSEGV, Segmentation fault.
(gdb) bt
#0  0x0000556c14759cb8 in expand_tuple (targetHeapTuple=targetHeapTuple@entry=0x0, 
    targetMinimalTuple=targetMinimalTuple@entry=0x7ffe8088a118, sourceTuple=<optimized out>, tupleDesc=<optimized
out>)
    at heaptuple.c:984
#1  0x0000556c1475bb46 in minimal_expand_tuple (sourceTuple=<optimized out>, tupleDesc=<optimized out>) at
heaptuple.c:1015
#2  0x0000556c14917177 in ExecCopySlotMinimalTuple (slot=<optimized out>) at execTuples.c:631
#3  0x0000556c14ba8ada in copytup_heap (state=0x556c16c4f5e8, stup=0x7ffe8088a180, tup=<optimized out>) at
tuplesort.c:3585
#4  0x0000556c14baf8e6 in tuplesort_puttupleslot (state=state@entry=0x556c16c4f5e8, slot=<optimized out>) at
tuplesort.c:1444
#5  0x0000556c14937791 in ExecSort (pstate=0x556c16c3ac50) at nodeSort.c:112
#6  0x0000556c1493c6f4 in ExecProcNode (node=0x556c16c3ac50) at ../../../src/include/executor/executor.h:239
#7  begin_partition (winstate=winstate@entry=0x556c16c3a6b8) at nodeWindowAgg.c:1110
#8  0x0000556c149403aa in ExecWindowAgg (pstate=0x556c16c3a6b8) at nodeWindowAgg.c:2094
#9  0x0000556c1490c0ca in ExecProcNode (node=0x556c16c3a6b8) at ../../../src/include/executor/executor.h:239
#10 ExecutePlan (execute_once=<optimized out>, dest=0x7f25481b5e88, direction=<optimized out>, numberTuples=0, 
    sendTuples=<optimized out>, operation=CMD_SELECT, use_parallel_mode=<optimized out>, planstate=0x556c16c3a6b8, 
    estate=0x556c16c1bbf8) at execMain.c:1729
#11 standard_ExecutorRun (queryDesc=0x556c16c250c8, direction=<optimized out>, count=0, execute_once=<optimized out>)
    at execMain.c:364
#12 0x0000556c14a6b40c in PortalRunSelect (portal=portal@entry=0x556c16b96468, forward=forward@entry=true, count=0, 
    count@entry=9223372036854775807, dest=dest@entry=0x7f25481b5e88) at pquery.c:937
#13 0x0000556c14a6ca90 in PortalRun (portal=portal@entry=0x556c16b96468, count=count@entry=9223372036854775807, 
    isTopLevel=isTopLevel@entry=true, run_once=run_once@entry=true, dest=dest@entry=0x7f25481b5e88, 
    altdest=altdest@entry=0x7f25481b5e88, completionTag=0x7ffe8088a500 "") at pquery.c:778
#14 0x0000556c14a6859b in exec_simple_query (
    query_string=0x556c16b2b438 "select\n  case when pg_catalog.lastval() <
pg_catalog.pg_stat_get_bgwriter_maxwritten_clean()then case when pg_catalog.circle_sub_pt(\n\t  cast(cast(null as
circle)as circle),\n\t  cast((select location "...) at postgres.c:1121
 
#15 0x0000556c14a6a341 in PostgresMain (argc=<optimized out>, argv=argv@entry=0x556c16b56ad8, dbname=<optimized out>, 
    username=<optimized out>) at postgres.c:4149
#16 0x0000556c1474eac4 in BackendRun (port=0x556c16b4c030) at postmaster.c:4409
#17 BackendStartup (port=0x556c16b4c030) at postmaster.c:4081
#18 ServerLoop () at postmaster.c:1754
#19 0x0000556c149ec017 in PostmasterMain (argc=3, argv=0x556c16b257d0) at postmaster.c:1362
#20 0x0000556c1475006d in main (argc=3, argv=0x556c16b257d0) at main.c:228