Simplify the setting of the kind in hashDerivationModulo

Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>

src/libstore/derivations.cc

@@ -510,7 +510,6 @@ static const DrvHashModulo pathDerivationModulo(Store & store, const StorePath &
  */
 DrvHashModulo hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutputs)
 {
-    auto kind = DrvHashModulo::Kind::Regular;
     /* Return a fixed hash for fixed-output derivations. */
     if(drv.type() == DerivationType::CAFixed) {
         std::map<std::string, Hash> outputHashes;
@@ -524,14 +523,19 @@ DrvHashModulo hashDerivationModulo(Store & store, const Derivation & drv, bool m
         }
         return DrvHashModulo{
             .hashes = outputHashes,
-            .kind = kind,
+            .kind = DrvHashModulo::Kind::Regular,
         };
-    } else if (drv.type() == DerivationType::CAFloating) {
-        kind = DrvHashModulo::Kind::Deferred;
     }
 
     /* For other derivations, replace the inputs paths with recursive
        calls to this function. */
+
+    auto kind = drv.type() == DerivationType::CAFloating
+        ? DrvHashModulo::Kind::Deferred
+        // Might be changed to `Deferred` below if we realise that one of the
+        // inputs has a Deferred hash
+        : DrvHashModulo::Kind::Regular;
+
     std::map<std::string, StringSet> inputs2;
     for (auto & [drvPath, inputOutputs0] : drv.inputDrvs) {
         // Avoid lambda capture restriction with standard / Clang