diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index 35ec3e4ab..b7baad375 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -178,16 +178,16 @@ Strings argvToStrings(int argc, char * * argv)
     return args;
 }
 
-Strings editorFor(std::string filename, int lineno)
+Strings editorFor(Pos pos)
 {
     auto editor = getEnv("EDITOR", "cat");
     auto args = tokenizeString<Strings>(editor);
-    if (lineno > 0 && (
+    if (pos.line > 0 && (
         editor.find("emacs") != std::string::npos ||
         editor.find("nano") != std::string::npos ||
         editor.find("vim") != std::string::npos))
-        args.push_back(fmt("+%d", lineno));
-    args.push_back(filename);
+        args.push_back(fmt("+%d", pos.line));
+    args.push_back(pos.file);
     return args;
 }
 
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index 22702c2d8..1e29bd4fa 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -5,6 +5,7 @@
 #include <memory>
 
 #include "util.hh"
+#include "nixexpr.hh"
 
 namespace nix {
 
@@ -191,7 +192,7 @@ public:
 Strings argvToStrings(int argc, char * * argv);
 
 /* Helper function to generate args that invoke $EDITOR on filename:lineno */
-Strings editorFor(std::string filename, int lineno);
+Strings editorFor(Pos pos);
 
 /* Helper function for rendering argument labels. */
 std::string renderLabels(const Strings & labels);
diff --git a/src/nix/edit.cc b/src/nix/edit.cc
index d0607747d..553765f13 100644
--- a/src/nix/edit.cc
+++ b/src/nix/edit.cc
@@ -37,12 +37,10 @@ struct CmdEdit : InstallableCommand
         auto v = installable->toValue(*state);
 
         Pos pos = findDerivationFilename(*state, *v, installable->what());
-        std::string filename(pos.file);
-        int lineno(pos.line);
 
         stopProgressBar();
 
-        auto args = editorFor(filename, lineno);
+        auto args = editorFor(pos);
 
         execvp(args.front().c_str(), stringsToCharPtrs(args).data());
 
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index ed67c285f..683a117f3 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -472,22 +472,19 @@ bool NixRepl::processLine(string line)
         Value v;
         evalString(arg, v);
 
-        std::string filename;
-        int lineno = 0;
+        Pos pos;
 
         if (v.type == tPath || v.type == tString) {
             PathSet context;
-            filename = state.coerceToString(noPos, v, context);
-            lineno = 0;
+            auto filename = state.coerceToString(noPos, v, context);
+            pos.file = state.symbols.create(filename);
         } else {
             // assume it's a derivation
-            Pos pos = findDerivationFilename(state, v, arg);
-            filename = pos.file;
-            lineno = pos.line;
+            pos = findDerivationFilename(state, v, arg);
         }
 
         // Open in EDITOR
-        auto args = editorFor(filename, lineno);
+        auto args = editorFor(pos);
         auto editor = args.front();
         args.pop_front();
         runProgram(editor, args);