diff --git a/build.nims b/build.nims
index 568b16f0..624f13c8 100644
--- a/build.nims
+++ b/build.nims
@@ -75,7 +75,7 @@ task coverage, "generates code coverage report":
     if f.endswith(".nim"): nimSrcs.add " " & f.absolutePath.quoteShell()
 
   echo "======== Running Tests ======== "
-  test "coverage", srcDir = "tests/", params = " --nimcache:nimcache/coverage -d:release "
+  test "coverage", srcDir = "tests/", params = " --nimcache:nimcache/coverage -d:release -d:codex_enable_proof_failures=true"
   exec("rm nimcache/coverage/*.c")
   rmDir("coverage"); mkDir("coverage")
   echo " ======== Running LCOV ======== "