Retrascope

Multiple sequential ranged assignments are needed to be merged into a single assignment.
For example (b10 itc design):

v_out : out bit_vector(3 downto 0)
...
v_out(0) <= voto0 ;
v_out(1) <= voto1 ;
v_out(2) <= voto2 ;
v_out(3) <= voto3 ;

This can be converted into the concatenation of bits:
v_out <= voto3 & voto2 & voto1 & voto0;

Something like:
v_out(0) <= voto0 ;
v_out(3) <= voto3 ;
is converted into:
v_out <= voto3 & v_out(2 downto 1) & voto0;

etc.