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, 3 insertions, 1 deletions

diff --git a/compiler/GHC/Runtime/Eval.hs b/compiler/GHC/Runtime/Eval.hs
index 24aed42125..d1cc9e56c1 100644
--- a/compiler/GHC/Runtime/Eval.hs
+++ b/compiler/GHC/Runtime/Eval.hs
@@ -108,6 +108,7 @@ import GHC.Types.Unique.Supply
 import GHC.Types.TyThing
 
 import GHC.Unit
+import GHC.Unit.Module.Graph
 import GHC.Unit.Module.ModIface
 import GHC.Unit.Module.ModSummary
 import GHC.Unit.Home.ModInfo
@@ -1214,7 +1215,8 @@ showModule mod_summary =
     withSession $ \hsc_env -> do
         interpreted <- moduleIsBootOrNotObjectLinkable mod_summary
         let dflags = hsc_dflags hsc_env
-        return (showSDoc dflags $ showModMsg dflags interpreted mod_summary)
+        -- extendModSummaryNoDeps because the message doesn't look at the deps
+        return (showSDoc dflags $ showModMsg dflags interpreted (ModuleNode (extendModSummaryNoDeps mod_summary)))
 
 moduleIsBootOrNotObjectLinkable :: GhcMonad m => ModSummary -> m Bool
 moduleIsBootOrNotObjectLinkable mod_summary = withSession $ \hsc_env ->