backslash in like expression causes query engine panic

create index ix100 on default(x) where y like "abc%";

select x from default where x > 20 and y like \"abc%\";

{

    "requestID": "9233dd9c-d0a1-4634-8bcd-19a3c75b674c",

    "errors": [

        {

            "code": 3000,

            "msg": "Error while parsing: runtime error: index out of range - at end of input"

        }

    ],

select x from default where x > 20 and y like "abc%";

{

    "requestID": "e4b7cbd1-e223-4ce6-8e1a-731e4d872db1",

    "signature": {

        "x": "json"

    },

    "results": [

    ],

    "status": "success",

    "metrics": {

        "elapsedTime": "7.467416ms",

        "executionTime": "7.441074ms",

        "resultCount": 0,

        "resultSize": 0

    }

}

create index ix101 on default(x);

explain select x from default where x like "";

{

    "requestID": "672aa1fa-22c2-41fc-8279-33cd58912475",

    "errors": [

        {

            "code": 3000,

            "msg": "Error while parsing: runtime error: index out of range - at end of input"

        }

    ],

    "status": "fatal",

    "metrics": {

        "elapsedTime": "2.548857ms",

        "executionTime": "2.52828ms",

        "resultCount": 0,

        "resultSize": 0,

        "errorCount": 1

    }

}

_time=2016-08-01T20:56:13.453-07:00 _level=ERROR _msg=Error while parsing: runtime error: index out of range
goroutine 67 [running]:
github.com/couchbase/query/parser/n1ql.doParse.func1(0xc820d83f20)
/Users/sitaram/query/src/github.com/couchbase/query/parser/n1ql/n1ql.go:69 +0x273
github.com/couchbase/query/expression.likeCompile(0x0, 0x0, 0x0, 0xc8200b2460, 0x0, 0x0)
/Users/sitaram/query/src/github.com/couchbase/query/expression/comp_like.go:140 +0x221
github.com/couchbase/query/expression.(*Like).precompile(0xc8206a3200)
/Users/sitaram/query/src/github.com/couchbase/query/expression/comp_like.go:116 +0x15f
github.com/couchbase/query/expression.NewLike(0x647d3f8, 0xc82057a180, 0x64b9dc8, 0xc82041d3e0, 0x0, 0x0)
/Users/sitaram/query/src/github.com/couchbase/query/expression/comp_like.go:39 +0x1ce
github.com/couchbase/query/parser/n1ql.(*yyParserImpl).Parse(0xc820a2a0d8, 0x6478660, 0xc820d83f20, 0x0)
n1ql.y:2083 +0x1fdb0
github.com/couchbase/query/parser/n1ql.yyParse(0x6478660, 0xc820d83f20, 0xc820d83f20)
yaccpar:154 +0x49
github.com/couchbase/query/parser/n1ql.doParse(0xc820d83f20)
/Users/sitaram/query/src/github.com/couchbase/query/parser/n1ql/n1ql.go:74 +0x73
github.com/couchbase/query/parser/n1ql.ParseStatement(0xc820d52680, 0x36, 0x0, 0x0, 0x0, 0x0)
/Users/sitaram/query/src/github.com/couchbase/query/parser/n1ql/n1ql.go:29 +0x21a
github.com/couchbase/query/server.(*Server).getPrepared(0xc8202b0b40, 0x6478470, 0xc8203e85a0, 0x4d850c8, 0x7, 0x0, 0x0, 0x0)
/Users/sitaram/query/src/github.com/couchbase/query/server/server.go:474 +0xd6
github.com/couchbase/query/server.(*Server).serviceRequest(0xc8202b0b40, 0x6478470, 0xc8203e85a0)
/Users/sitaram/query/src/github.com/couchbase/query/server/server.go:408 +0xea
github.com/couchbase/query/server.(*Server).doServe(0xc8202b0b40)
/Users/sitaram/query/src/github.com/couchbase/query/server/server.go:355 +0x134
created by github.com/couchbase/query/server.(*Server).Serve
/Users/sitaram/query/src/github.com/couchbase/query/server/server.go:345 +0x84