[BUG] Sequences using variables causes a parse error

[ninmonkey]

Expected behavior
Valid queries should not raise a a parse error. It runs as expected in Power BI.

Actual behavior

Expected to find a right brace <'}'>, but a keyword <'in'> was found insteadpowerquery(Error.Parse)

To Reproduce: Case 1

let
    start = 0, 
    end = 10,
    sequence = {start..end}
in
    sequence

Expected to find a right brace <'}'>, but a keyword <'in'> was found insteadpowerquery(Error.Parse)

To Reproduce: Case 2

let
    start = 10,
    Numbers = {start..10}
in 
    Numbers

Expected to find a right brace <'}'>, but a numeric literal was found insteadpowerquery(Error.Parse)

Working case

let
    end = 10,
    Numbers = {0..end}
in 
    Numbers

[JordanBoltonMN]

Found the issue. It's that the lexer is generating an identifier token start. which shouldn't be valid, as identifiers do not allow trailing commas.