- List.concat [[]];
stdIn:1.2-435.13 Warning: type vars not generalized because of
   value restriction are instantiated to dummy types (X1,X2,...)
val it = [] : ?.X1 list

- fun f a = a
=   | f 1 = 1;
stdIn:371.5-372.12 Error: match redundant
          a => ...
    -->   1 => ...

- fun f a b = a = b;
stdIn:348.14 Warning: calling polyEqual
val f = fn : ''a -> ''a -> bool

- fun f a = #1 a;
stdIn:369.1-369.15 Error: unresolved flex record
   (can't tell what fields there are besides #1)