PR#6529: fix quadratic-time algorithm in Consistbl.extract.


git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@15169 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Use module_binding in Pexp_letmodule / Texp_letmodule
Introduce Asttypes.arrow_flag to encode labelled arguments
Split arrow_flag into Parsetree.arrow_flag and Types.arrow_flag
Remove Typedtree.optional, as its purpose was redundant.
WIP: refining arrow_flag with apply_flag
Introduce Asttypes.arrow_flag to encode labelled arguments
Introduce Asttypes.arrow_flag to encode labelled arguments
Introduce "implicit" keyword and constructions in parser
WIP introducing implicit in typing
Make ocaml compile, add TODOs for implicit in typer
Change representation of implicits in AST
Introduce implicits in Typedtree
WIP: toplevel is working
Fix tools, leave FIXMEs in ocamldoc
Add Implicit flag to arrow_flag
WIP, generalizing arrows
WIP3
Introduce "let implicit _ in _" expression
Get rid of Ppat_implicit