diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ab178a35..b5f0c78c 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -107,7 +107,6 @@ jobs:
           osversion_xcodeversion_toxenv_tuples: >-
             [["latest", "",           "homebrew-macos-usrlocal-minimal"],
              ["latest", "",           "homebrew-macos-usrlocal-standard"],
-             ["13",     "xcode_15.0", "homebrew-macos-usrlocal-standard"],
              ["latest", "",           "conda-forge-macos-standard"]]
           targets:           SAGE_CHECK=no SAGE_CHECK_PACKAGES="cypari" cypari
           # Standard setting: Test the current beta release of Sage
diff --git a/cypari2/stack.pyx b/cypari2/stack.pyx
index 95a7f1b6..d000cc99 100644
--- a/cypari2/stack.pyx
+++ b/cypari2/stack.pyx
@@ -22,7 +22,6 @@ from cpython.exc cimport PyErr_SetString
 
 from cysignals.signals cimport (sig_on, sig_off, sig_block, sig_unblock,
                                 sig_error)
-from cysignals.memory cimport check_malloc, sig_free
 
 from .gen cimport Gen, Gen_new
 from .paridecl cimport (avma, pari_mainstack, gnil, gcopy,