Add missing primop documentation (#18454)

- Add three pseudoops to primops.txt.pp, so that Haddock renders
  the documentation
- Update comments
- Remove special case for "->" - it's no longer exported from GHC.Prim
- Remove reference to Note [Compiling GHC.Prim] - the ad-hoc fix is no
  longer there after updates to levity polymorphism.
- Document GHC.Prim
- Remove the comment that lazy is levity-polymorphic.
  As far as I can tell, it never was: in 80e399639,
  only the unfolding was given an open type variable.
- Remove haddock hack in GHC.Magic - no longer neccessary after
  adding realWorld# to primops.txt.pp.

2 files changed, 3 insertions, 4 deletions

diff --git a/utils/genprimopcode/Main.hs b/utils/genprimopcode/Main.hs
index a817c75a0d..36daa45a52 100644
--- a/utils/genprimopcode/Main.hs
+++ b/utils/genprimopcode/Main.hs
@@ -1,5 +1,7 @@
 ------------------------------------------------------------------
 -- A primop-table mangling program                              --
+--
+-- See Note [GHC.Prim] in primops.txt.pp for details.
 ------------------------------------------------------------------
 
 module Main where
@@ -293,8 +295,6 @@ gen_hs_source (Info defaults entries) =
            hdr (PrimOpSpec { name = n })                         = wrapOp n ++ ","
            hdr (PrimVecOpSpec { name = n })                      = wrapOp n ++ ","
            hdr (PseudoOpSpec { name = n })                       = wrapOp n ++ ","
-           hdr (PrimTypeSpec { ty = TyApp (TyCon "->") _ })      = ""
-                  -- GHC lacks the syntax to explicitly export "->"
            hdr (PrimTypeSpec { ty = TyApp (TyCon n) _ })         = wrapOp n ++ ","
            hdr (PrimTypeSpec {})                                 = error $ "Illegal type spec"
            hdr (PrimVecTypeSpec { ty = TyApp (VecTyCon n _) _ }) = wrapOp n ++ ","
@@ -398,8 +398,6 @@ keep GHC's renamer and typechecker happy enough for what Haddock
 needs.  Our main plan is to say
         foo :: <type>
         foo = foo
-We have to silence GHC's complaints about unboxed-top-level declarations
-with an ad-hoc fix in GHC.Tc.Gen.Bind: see Note [Compiling GHC.Prim] in GHC.Tc.Gen.Bind.
 
 That works for all the primitive functions except tagToEnum#.
 If we generate the binding
diff --git a/utils/genprimopcode/Parser.y b/utils/genprimopcode/Parser.y
index efcfee0889..f39af24c7c 100644
--- a/utils/genprimopcode/Parser.y
+++ b/utils/genprimopcode/Parser.y
@@ -163,6 +163,7 @@ paT : pTycon ppTs     { TyApp $1 $2 }
 
 pUnboxedTupleTy :: { Ty }
 pUnboxedTupleTy : '(#' pCommaTypes '#)' { TyUTup $2 }
+                | '(#' '#)' { TyUTup [] }
 
 pCommaTypes :: { [Ty] }
 pCommaTypes : pType ',' pCommaTypes { $1 : $3 }