Properly take the last assignment in the REPL

When a variable is assigned in the REPL, make sure to remove any possible reference to the old one so that we correctly pick the new one afterwards

Fix #5706

1 files changed, 2 insertions, 0 deletions

diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index 42143871f..f453343f3 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -672,6 +672,8 @@ void NixRepl::addVarToScope(const Symbol & name, Value & v)
 {
     if (displ >= envSize)
         throw Error("environment full; cannot add more variables");
+    if (auto oldVar = staticEnv.find(name); oldVar != staticEnv.vars.end())
+        staticEnv.vars.erase(oldVar);
     staticEnv.vars.emplace_back(name, displ);
     staticEnv.sort();
     env->values[displ++] = &v;