diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 1485dc7fe..064b1a623 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -18,7 +18,7 @@ namespace nix {
 
 class Store;
 class EvalState;
-struct StorePath;
+class StorePath;
 enum RepairFlag : bool;
 
 
diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index f8eff508c..9f52ddafa 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -388,8 +388,6 @@ void BinaryCacheStore::addSignatures(const StorePath & storePath, const StringSe
 
     narInfo->sigs.insert(sigs.begin(), sigs.end());
 
-    auto narInfoFile = narInfoFileFor(narInfo->path);
-
     writeNarInfo(narInfo);
 }
 
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index e1d812b09..3afebfcf4 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -86,7 +86,7 @@ struct HookInstance;
 
 
 /* A pointer to a goal. */
-class Goal;
+struct Goal;
 class DerivationGoal;
 typedef std::shared_ptr<Goal> GoalPtr;
 typedef std::weak_ptr<Goal> WeakGoalPtr;