1 files changed, 8 insertions, 10 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index e71e3a6d46cb..8ace6db4d11d 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -1359,7 +1359,6 @@ static void prim_functionArgs(EvalState & state, const Pos & pos, Value * * args
 /* Apply a function to every element of an attribute set. */
 static void prim_mapAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    state.forceFunction(*args[0], pos);
     state.forceAttrs(*args[1], pos);
 
     state.mkAttrs(v, args[1]->attrs->size());
@@ -1368,7 +1367,7 @@ static void prim_mapAttrs(EvalState & state, const Pos & pos, Value * * args, Va
         Value * vName = state.allocValue();
         Value * vFun2 = state.allocValue();
         mkString(*vName, i.name);
-        state.callFunction(*args[0], *vName, *vFun2, pos);
+        mkApp(*vFun2, *args[0], *vName);
         mkApp(*state.allocAttr(v, i.name), *vFun2, *i.value);
     }
 }
@@ -1429,7 +1428,6 @@ static void prim_tail(EvalState & state, const Pos & pos, Value * * args, Value
 /* Apply a function to every element of a list. */
 static void prim_map(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    state.forceFunction(*args[0], pos);
     state.forceList(*args[1], pos);
 
     state.mkList(v, args[1]->listSize());
@@ -1508,19 +1506,20 @@ static void prim_foldlStrict(EvalState & state, const Pos & pos, Value * * args,
     state.forceFunction(*args[0], pos);
     state.forceList(*args[2], pos);
 
-    Value * vCur = args[1];
+    if (args[2]->listSize()) {
+        Value * vCur = args[1];
 
-    if (args[2]->listSize())
         for (unsigned int n = 0; n < args[2]->listSize(); ++n) {
             Value vTmp;
             state.callFunction(*args[0], *vCur, vTmp, pos);
             vCur = n == args[2]->listSize() - 1 ? &v : state.allocValue();
             state.callFunction(vTmp, *args[2]->listElems()[n], *vCur, pos);
         }
-    else
-        v = *vCur;
-
-    state.forceValue(v);
+        state.forceValue(v);
+    } else {
+        state.forceValue(*args[1]);
+        v = *args[1];
+    }
 }
 
 
@@ -1557,7 +1556,6 @@ static void prim_all(EvalState & state, const Pos & pos, Value * * args, Value &
 
 static void prim_genList(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    state.forceFunction(*args[0], pos);
     auto len = state.forceInt(*args[1], pos);
 
     if (len < 0)