Fix #11141 broken sp corrector

tests/functional/lang-gc.sh

@@ -0,0 +1,34 @@
+# shellcheck shell=bash
+
+# Regression tests for the evaluator
+# These are not in lang.sh because they generally only need to run in CI,
+# whereas lang.sh is often run locally during development
+
+
+source common.sh
+
+set -o pipefail
+
+# Regression test for #11141. The stack pointer corrector assigned the base
+# instead of the top (which resides at the low end of the stack). Sounds confusing?
+# Stacks grow downwards, so that's why this mistake happened.
+# My manual testing did not uncover this, because it didn't rely on the stack enough.
+# https://github.com/NixOS/nix/issues/11141
+test_issue_11141() {
+  mkdir -p "$TEST_ROOT/issue-11141/src"
+  cp lang-gc/issue-11141-gc-coroutine-test.nix "$TEST_ROOT/issue-11141/"
+  (
+    set +x;
+    n=10
+    echo "populating $TEST_ROOT/issue-11141/src with $((n*100)) files..."
+    for i in $(seq 0 $n); do
+      touch "$TEST_ROOT/issue-11141/src/file-$i"{0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9}
+    done
+  )
+
+  GC_INITIAL_HEAP_SIZE=$((1024 * 1024)) \
+  NIX_SHOW_STATS=1 \
+  nix eval -vvv\
+    -f "$TEST_ROOT/issue-11141/issue-11141-gc-coroutine-test.nix"
+}
+test_issue_11141