`typeof(missingval)` should be a subtype of `eltype`

[mauro3]

Consider

ras = Raster(rand(Int32, X(25:1:30), Y(25:1:30)), missingval=-1.5)

Is allowing the type of missingval not being a subtype of the eltype useful for anything?

The reason I came across this is that it took me ages to figure out what was wrong here:

julia> ras = Raster(rand(Int32, X(25:1:30), Y(25:1:30)), missingval=-1)

6×6 Raster{Int32,2} with dimensions: 
  X Sampled{Int64} 25:1:30 ForwardOrdered Regular Points,
  Y Sampled{Int64} 25:1:30 ForwardOrdered Regular Points
extent: Extent(X = (25, 30), Y = (25, 30))
missingval: -1
parent:
              25           26           27           28          29           30
 25  -1577965140   -930532794  -1069034332  -1869000944  -876112444  -1896541373
 26  -2119450237   2112008256   -574130295    234237348   295379253  -1608673699
 27    479548452   1163904508  -1753155508   -779730610  -508137957   -545965278
 28   -518000084  -1234244315   2027127016  -1383270083  1182867062   1198615452
 29   -575807158    253215731    731658899  -1561393151  2005117126   1945068211
 30  -1836660204  -1824357014   -734002877    853304731  1129518778  -1924398571

julia> write("/tmp/band.tif", ras, force=true)
ERROR: GDALError (CE_Failure, code 1):
        GetNoDataValue() should be called instead

Stacktrace:
...

which can be fixed with

julia> ras = Raster(rand(Int32, X(25:1:30), Y(25:1:30)), missingval=Int32(-1));
julia> write("/tmp/band.tif", ras, force=true)

Anyways, should there be a conversion missingval = convert(eltyp(data), missingval)?