Put hole instantiation typechecking in the module graph and fix driver batch mode backpack edges

Backpack instantiations need to be typechecked to make sure that the
arguments fit the parameters. `tcRnInstantiateSignature` checks
instantiations with concrete modules, while `tcRnCheckUnit` checks
instantiations with free holes (signatures in the current modules).

Before this change, it worked that `tcRnInstantiateSignature` was called
after typechecking the argument module, see `HscMain.hsc_typecheck`,
while `tcRnCheckUnit` was called in `unsweep'` where-bound in
`GhcMake.upsweep`. `tcRnCheckUnit` was called once per each
instantiation once all the argument sigs were processed. This was done
with simple "to do" and "already done" accumulators in the fold.
`parUpsweep` did not implement the change.

With this change, `tcRnCheckUnit` instead is associated with its own
node in the `ModuleGraph`. Nodes are now:
```haskell
data ModuleGraphNode
  -- | Instantiation nodes track the instantiation of other units
  -- (backpack dependencies) with the holes (signatures) of the current package.
  = InstantiationNode InstantiatedUnit
  -- | There is a module summary node for each module, signature, and boot module being built.
  | ModuleNode ExtendedModSummary
```
instead of just `ModSummary`; the `InstantiationNode` case is the
instantiation of a unit to be checked. The dependencies of such nodes
are the same "free holes" as was checked with the accumulator before.
Both versions of upsweep on such a node call `tcRnCheckUnit`.

There previously was an `implicitRequirements` function which would
crawl through every non-current-unit module dep to look for all free
holes (signatures) to add as dependencies in `GHC.Driver.Make`. But this
is no good: we shouldn't be looking for transitive anything when
building the graph: the graph should only have immediate edges and the
scheduler takes care that all transitive requirements are met.

So `GHC.Driver.Make` stopped using `implicitRequirements`, and instead
uses a new `implicitRequirementsShallow`, which just returns the
outermost instantiation node (or module name if the immediate dependency
is itself a signature). The signature dependencies are just treated like
any other imported module, but the module ones then go in a list stored
in the `ModuleNode` next to the `ModSummary` as the "extra backpack
dependencies". When `downsweep` creates the mod summaries, it adds this
information too.

------

There is one code quality, and possible correctness thing left: In
addition to `implicitRequirements` there is `findExtraSigImports`, which
says something like "if you are an instantiation argument (you are
substituted or a signature), you need to import its things too".  This
is a little non-local so I am not quite sure how to get rid of it in
`GHC.Driver.Make`, but we probably should eventually.

First though, let's try to make a test case that observes that we don't
do this, lest it actually be unneeded. Until then, I'm happy to leave it
as is.

------

Beside the ability to use `-j`, the other major user-visibile side
effect of this change is that that the --make progress log now includes
"Instantiating" messages for these new nodes. Those also are numbered
like module nodes and count towards the total.

------

Fixes #17188

Updates hackage submomdule

Metric Increase:
    T12425
    T13035

1 files changed, 25 insertions, 32 deletions

diff --git a/compiler/GHC/Unit/Module/ModSummary.hs b/compiler/GHC/Unit/Module/ModSummary.hs
index a0b42fc2a4..e9106d44eb 100644
--- a/compiler/GHC/Unit/Module/ModSummary.hs
+++ b/compiler/GHC/Unit/Module/ModSummary.hs
@@ -1,7 +1,11 @@
+{-# LANGUAGE LambdaCase #-}
+
 -- | A ModSummary is a node in the compilation manager's dependency graph
 -- (ModuleGraph)
 module GHC.Unit.Module.ModSummary
-   ( ModSummary (..)
+   ( ExtendedModSummary (..)
+   , extendModSummaryNoDeps
+   , ModSummary (..)
    , ms_installed_mod
    , ms_mod_name
    , ms_imps
@@ -13,7 +17,6 @@ module GHC.Unit.Module.ModSummary
    , msObjFilePath
    , msDynObjFilePath
    , isBootSummary
-   , showModMsg
    , findTarget
    )
 where
@@ -22,9 +25,7 @@ import GHC.Prelude
 
 import GHC.Hs
 
-import GHC.Driver.Ppr
 import GHC.Driver.Session
-import GHC.Driver.Backend
 
 import GHC.Unit.Types
 import GHC.Unit.Module
@@ -40,9 +41,24 @@ import GHC.Data.StringBuffer ( StringBuffer )
 import GHC.Utils.Outputable
 
 import Data.Time
-import System.FilePath
 
--- | A single node in a 'ModuleGraph'. The nodes of the module graph
+-- | Enrichment of 'ModSummary' with backpack dependencies
+data ExtendedModSummary = ExtendedModSummary
+  { emsModSummary :: {-# UNPACK #-} !ModSummary
+  , emsInstantiatedUnits :: [InstantiatedUnit]
+  -- ^ Extra backpack deps
+  -- NB: This is sometimes left empty in situations where the instantiated units
+  -- would not be used. See call sites of 'extendModSummaryNoDeps'.
+  }
+
+instance Outputable ExtendedModSummary where
+  ppr = \case
+    ExtendedModSummary ms bds -> ppr ms <+> ppr bds
+
+extendModSummaryNoDeps :: ModSummary -> ExtendedModSummary
+extendModSummaryNoDeps ms = ExtendedModSummary ms []
+
+-- | Data for a module node in a 'ModuleGraph'. Module nodes of the module graph
 -- are one of:
 --
 -- * A regular Haskell source module
@@ -53,7 +69,7 @@ data ModSummary
         ms_mod          :: Module,
           -- ^ Identity of the module
         ms_hsc_src      :: HscSource,
-          -- ^ The module source either plain Haskell or hs-boot
+          -- ^ The module source either plain Haskell, hs-boot, or hsig
         ms_location     :: ModLocation,
           -- ^ Location of the various files belonging to the module
         ms_hs_date      :: UTCTime,
@@ -150,31 +166,6 @@ instance Outputable ModSummary where
              char '}'
             ]
 
-showModMsg :: DynFlags -> Bool -> ModSummary -> SDoc
-showModMsg dflags recomp mod_summary =
-   if gopt Opt_HideSourcePaths dflags
-      then text mod_str
-      else hsep $
-         [ text (mod_str ++ replicate (max 0 (16 - length mod_str)) ' ')
-         , char '('
-         , text (op $ msHsFilePath mod_summary) <> char ','
-         ] ++
-         if gopt Opt_BuildDynamicToo dflags
-            then [ text obj_file <> char ','
-                 , text dyn_file
-                 , char ')'
-                 ]
-            else [ text obj_file, char ')' ]
-  where
-    op       = normalise
-    mod      = moduleName (ms_mod mod_summary)
-    mod_str  = showPpr dflags mod ++ hscSourceString (ms_hsc_src mod_summary)
-    dyn_file = op $ msDynObjFilePath mod_summary dflags
-    obj_file = case backend dflags of
-                Interpreter | recomp -> "interpreted"
-                NoBackend            -> "nothing"
-                _                    -> (op $ msObjFilePath mod_summary)
-
 findTarget :: ModSummary -> [Target] -> Maybe Target
 findTarget ms ts =
   case filter (matches ms) ts of
@@ -188,3 +179,5 @@ findTarget ms ts =
         = f == f'
     _ `matches` _
         = False
+
+