diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 9a04432e0..8fd25ea15 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -937,10 +937,16 @@ static void prim_hashFile(EvalState & state, const Pos & pos, Value * * args, Va
     if (ht == htUnknown)
       throw Error(format("unknown hash type '%1%', at %2%") % type % pos);
 
-    PathSet context; // discarded
-    Path p = state.coerceToPath(pos, *args[1], context);
+    PathSet context;
+    Path path = state.coerceToPath(pos, *args[1], context);
+    try {
+        state.realiseContext(context);
+    } catch (InvalidPathError & e) {
+        throw EvalError(format("cannot read '%1%', since path '%2%' is not valid, at %3%")
+            % path % e.path % pos);
+    }
 
-    mkString(v, hashFile(ht, state.checkSourcePath(p)).to_string(Base16, false), context);
+    mkString(v, hashFile(ht, state.checkSourcePath(state.toRealPath(path, context))).to_string(Base16, false));
 }
 
 /* Read a directory (without . or ..) */
@@ -1821,7 +1827,7 @@ static void prim_hashString(EvalState & state, const Pos & pos, Value * * args,
     PathSet context; // discarded
     string s = state.forceString(*args[1], context, pos);
 
-    mkString(v, hashString(ht, s).to_string(Base16, false), context);
+    mkString(v, hashString(ht, s).to_string(Base16, false));
 }