Fix GPR#1204

[garrigue]

Another way to fix #1204, by setting row_name in Typedecl, as suggested by @lpw25.

[lpw25]

Looks good to me

[lpw25]

As a side-note, with this patch the type definition

type 'a t = [`A of 'a] as 'a;;

gets printed by the top-level printer in a way that is not accepted by the type-checker:

# type 'a t = [`A of 'a] as 'a;;
type 'a t = [ `A of 'a ] constraint 'a = 'a t

# type 'a t = [ `A of 'a ] constraint 'a = 'a t;;
Characters 0-45:
  type 'a t = [ `A of 'a ] constraint 'a = 'a t;;
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error: The type abbreviation t is cyclic

However, this isn't a new bug from this code, as you could already get the same thing with a slightly different type in 4.04.1:

# type 'a t = [ `A of 'a t ] as 'a;;
type 'a t = [ `A of 'a t ] constraint 'a = 'a t

# type 'a t = [ `A of 'a t ] constraint 'a = 'a t;;
Characters 0-47:
  type 'a t = [ `A of 'a t ] constraint 'a = 'a t;;
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error: The type abbreviation t is cyclic

[garrigue]

Indeed, the problem does not seem directly related to this fix.

However, this fix may have some impact on tools using the internal type representation for printing, in particular if they do not call the proper functions from Printtyp.
tests/tool-ocamldoc/t01.ml failed printing the type name as right hand of the equation.
I fixed this by pasting the same code as in Printtyp.tree_of_type_declaration , but I wonder how odoc does for instance.

[lpw25]

odoc carefully copies the behaviour of the functions in Printtyp so it should be fine.

[garrigue]

Attempted a slightly different approach, adding the row name in Env just where the descriptions for record fields and variant constructors are generated. This avoids having to modify ocamldoc (and possibly other tools too).

[lpw25]

It's much less clear that this new version is correct. It looks like it will only add row names to types coming from other modules. I think it would be better to use the version you had before.