data.dot

digraph {
  graph [pad="0.5", nodesep="0.25", ranksep="0.85"];
  node [color="#5e6687", shape="box"];
  edge [color="#5e6687", arrowhead="empty", arrowtail="empty"];

  subgraph cluster_legend {
    node [fillcolor=none, shape=plaintext]
    key [label=<<table border="0" cellpadding="2" cellspacing="0" cellborder="0">
         <tr><td align="right" port="i1">Foo.to_bar</td></tr>
         <tr><td height="30px" align="right" port="i2">Bar.of_foo</td></tr>
         <tr><td align="right" port="i3">(partial)</td></tr>
         </table>>]
    key2 [label=<<table border="0" cellpadding="2" cellspacing="0" cellborder="0">
          <tr><td port="i1">&nbsp;</td></tr>
          <tr><td height="30px" port="i2">&nbsp;</td></tr>
          <tr><td port="i3">&nbsp;</td></tr>
          </table>>]
    key:i1:e -> key2:i1:w [color=green]
    key:i2:e -> key2:i2:w [color=red]
    key:i3:e -> key2:i3:w [style=dashed]
  }

  // Int & Float
  Int -> Float [color=green, dir=both]
  Float -> Int [color=red, dir=both]

  // Int32
  Int32 -> Int [color=green]
  Int32 -> Float [color=green]
  Int -> Int32 [color=red]
  Float -> Int32 [color=red]

  // Int64
  Int64 -> Int [color=green]
  Int64 -> Int32 [color=green]
  Int64 -> Nativeint [color=green]
  Int64 -> Float [color=green]
  Int -> Int64 [color=red]
  Int32 -> Int64 [color=red]
  Nativeint -> Int64 [color=red]
  Float -> Int64 [color=red]

  // Nativeint
  Nativeint -> Int [color=green]
  Nativeint -> Int32 [color=green]
  Nativeint -> Float [color=green]
  Int -> Nativeint [color=red]
  Int32 -> Nativeint [color=red]
  Float -> Nativeint [color=red]

  // Char
  Char -> Int [color=green]
  Int -> Char [style=dashed, color=red]

  // Bool
  Bool -> Int [color=green]
  Bool -> Float [color=green]

  // Bytes

  // Uchar
  Uchar -> Int [color=green]
  Uchar -> Char [style=dashed, color=green]
  Int -> Uchar [style=dashed, color=red]
  Char -> Uchar [color=red]

  // Unit
}