diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 5a1f47b55..87ee4f68a 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -1374,7 +1374,7 @@ static void prim_genList(EvalState & state, const Pos & pos, Value * * args, Val
 
     state.mkList(v, len);
 
-    for (unsigned int n = 0; n < len; ++n) {
+    for (unsigned int n = 0; n < (unsigned int) len; ++n) {
         Value * arg = state.allocValue();
         mkInt(*arg, n);
         mkApp(*(v.listElems()[n] = state.allocValue()), *args[0], *arg);
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 54f905798..a124b2b14 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -3731,7 +3731,7 @@ void Worker::waitForInput()
         }
     }
 
-    if (!waitingForAWhile.empty() && lastWokenUp + settings.pollInterval <= after) {
+    if (!waitingForAWhile.empty() && lastWokenUp + (time_t) settings.pollInterval <= after) {
         lastWokenUp = after;
         for (auto & i : waitingForAWhile) {
             GoalPtr goal = i.lock();