Faulty code generation when using `metadata` with `min`/`max` operation

[SimonCockx]

This sample fails with a compilation error:

func Test:
    inputs:
        foo Foo (1..*)
    output:
        result number (0..1)

    set result:
        foo -> bar
            max [ attr ]
            then extract value

type Foo:
    bar Bar (1..*)
        [metadata location]

type Bar:
    attr string (1..1)
    value number (1..1)

This one fails with a different error:

func Test:
    inputs:
        bar Bar (1..*)
            [metadata location]
    output:
        result Bar (0..1)

    set result:
        bar
            max [ attr ]

type Bar:
    attr string (1..1)