MatrixObj doesn't check the ncols - while creating

[mihalova]

Observed behaviour

I created the MatrixObj with the command Matrix( R, list, ncols ). As list I put an 1x3 matrix, but for the ncols parameter I put 4. However, the MatrixObj was created. I tried to access the element (1,4) and GAP gave me an error.

Expected behaviour

I would expect either change in the ncols parameter or adding an empty elements to the matrix.

GAP example

gap> mat:=Matrix(Integers, [[1,2,3]], 4); 
<1x4-matrix over Integers>
gap> Print(mat);
NewMatrix(IsPlistMatrixRep,Integers,4,[ [ 1, 2, 3 ] ])
gap> mat[1,4];
Error, List Element: <list>[4] must have an assigned value in
  return m![ROWSPOS][row]![ELSPOS][col]
 ; at /Users/dominika/gap-4.12.0/lib/matobjplist.gi:824 called from 
<function "MatElm for a plist matrix and two positions">( <arguments> )
 called from read-eval loop at *stdin*:129
type 'quit;' to quit to outer loop