Window frame reference CTE variable panics

WITH noffset AS (2)

SELECT b.name,

       ARRAY_AGG(b) OVER (ORDER BY b.name ROWS BETWEEN 2*noffset PRECEDING AND 2*noffset FOLLOWING) AS docs

FROM [{"name":"option 1"},{"name":"option 2"},{"name":"option 3"},{"name":"option 4"},{"name":"option 5"},{"name":"option 6"},{"name":"option 7"},{"name":"option 8"} ]  AS b

WHERE b.name IS NOT NULL;

_time=2021-02-14T11:10:00.486-08:00 _level=SEVERE _msg=panic: runtime error: invalid memory address or nil pointer dereference

_time=2021-02-14T11:10:00.486-08:00 _level=SEVERE _msg=request text: <ud>WITH noffset AS (2) SELECT b.name, ARRAY_AGG(b) OVER (ORDER BY b.name ROWS BETWEEN 2*noffset PRECEDING AND 2*noffset FOLLOWING) AS docs FROM [{"name":"option 1"},{"name":"option 2"},{"name":"option 3"},{"name":"option 4"},{"name":"option 5"},{"name":"option 6"},{"name":"option 7"},{"name":"option 8"} ]  AS b WHERE b.name IS NOT NULL;</ud>

_time=2021-02-14T11:10:00.486-08:00 _level=SEVERE _msg=query context: <ud></ud>

_time=2021-02-14T11:10:00.486-08:00 _level=SEVERE _msg=stack: goroutine 275 [running]:

github.com/couchbase/query/execution.(*Context).Recover(0xc000c69680, 0xc000dcc000)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/context.go:921 +0xbb

panic(0x546a000, 0x6b55c70)

	/usr/local/Cellar/go/1.13.7/libexec/src/runtime/panic.go:679 +0x1b2

github.com/couchbase/query/execution.(*base).close(0xc000dcc000, 0xc000c69680)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/base.go:270 +0x22a

panic(0x546a000, 0x6b55c70)

	/usr/local/Cellar/go/1.13.7/libexec/src/runtime/panic.go:679 +0x1b2

github.com/couchbase/query/execution.(*base).notify(0xc000dcc000)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/base.go:975 +0x6e

panic(0x546a000, 0x6b55c70)

	/usr/local/Cellar/go/1.13.7/libexec/src/runtime/panic.go:679 +0x1b2

github.com/couchbase/query/expression.(*Identifier).Evaluate(0xc000142dc0, 0x0, 0x0, 0x5a41d00, 0xc000c69680, 0x5a63960, 0xc0000414c0, 0x0, 0x0)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/expression/identifier.go:64 +0x22

github.com/couchbase/query/expression.(*Mult).Evaluate(0xc00052cd70, 0x0, 0x0, 0x5a41d00, 0xc000c69680, 0xc000de9b20, 0x404809c, 0x10, 0x56511c0)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/expression/arith_mult.go:52 +0xdc

github.com/couchbase/query/execution.(*AggregateInfo).windowValidateValExpr(0xc000b4ec30, 0x5a71c20, 0xc00052cd70, 0xc000b15100, 0xc000c69680, 0x7f9ad98, 0x0, 0x6c99f8a51996613d, 0x0)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/window.go:872 +0x56

github.com/couchbase/query/execution.(*AggregateInfo).setOnce(0xc000b4ec30, 0xc000c69680, 0x71, 0x0)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/window.go:300 +0x315

github.com/couchbase/query/execution.(*WindowAggregate).setupTerms(0xc000dcc000, 0xc000c69680, 0x0)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/window.go:193 +0x6dd

github.com/couchbase/query/execution.(*WindowAggregate).beforeItems(0xc000dcc000, 0xc000c69680, 0x5a62f40, 0xc00014b400, 0x0)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/window.go:974 +0x35

github.com/couchbase/query/execution.(*base).runConsumer.func1()

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/base.go:887 +0x284

github.com/couchbase/query/util.(*Once).Do(0xc000dcc138, 0xc000de9ec8)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/util/sync.go:57 +0x4a

github.com/couchbase/query/execution.(*base).runConsumer(0xc000dcc000, 0x5a30d80, 0xc000dcc000, 0xc000c69680, 0x5a62f40, 0xc00014b400)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/base.go:847 +0xa2

github.com/couchbase/query/execution.(*WindowAggregate).RunOnce(0xc000dcc000, 0xc000c69680, 0x5a62f40, 0xc00014b400)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/window.go:970 +0x99

github.com/couchbase/query/execution.execOp(0x5a80d60, 0xc000dcc000, 0xc000c69680, 0x5a62f40, 0xc00014b400)

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/base.go:506 +0x54

created by github.com/couchbase/query/execution.(*base).fork

	/Users/sitaram/trans/query/src/github.com/couchbase/query/execution/base.go:517 +0x103