Fixing #7479

Types converted:

- `NixStringContextElem`
- `OutputsSpec`
- `ExtendedOutputsSpec`
- `DerivationOutput`
- `DerivationType`

Existing ones mostly conforming the pattern cleaned up:

- `ContentAddressMethod`
- `ContentAddressWithReferences`

The `DerivationGoal::derivationType` field had a bogus initialization,
now caught, so I made it `std::optional`. I think #8829 can make it
non-optional again because it will ensure we always have the derivation
when we construct a `DerivationGoal`.

See that issue (#7479) for details on the general goal.

`git grep 'Raw::Raw'` indicates the two types I didn't yet convert
`DerivedPath` and `BuiltPath` (and their `Single` variants) . This is
because @roberth and I (can't find issue right now...) plan on reworking
them somewhat, so I didn't want to churn them more just yet.

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstore/build/derivation-goal.hh b/src/libstore/build/derivation-goal.hh
index ee8f06f25..9d6fe1c0f 100644
--- a/src/libstore/build/derivation-goal.hh
+++ b/src/libstore/build/derivation-goal.hh
@@ -184,7 +184,7 @@ struct DerivationGoal : public Goal
     /**
      * The sort of derivation we are building.
      */
-    DerivationType derivationType;
+    std::optional<DerivationType> derivationType;
 
     typedef void (DerivationGoal::*GoalState)();
     GoalState state;