diff --git a/.github/workflows/sanitize.yml b/.github/workflows/sanitize.yml
index bb085eae..834c5ab4 100644
--- a/.github/workflows/sanitize.yml
+++ b/.github/workflows/sanitize.yml
@@ -41,6 +41,7 @@ jobs:
 
     - name: Run main tests with address sanitizer (ASAN)
       env:
+        ASAN_OPTIONS: halt_on_error=1
         CFLAGS: -fsanitize=address
         RUSTFLAGS: -Zsanitizer=address
       run: |
diff --git a/cli/src/tests/corpus_test.rs b/cli/src/tests/corpus_test.rs
index a193c029..f7b4815b 100644
--- a/cli/src/tests/corpus_test.rs
+++ b/cli/src/tests/corpus_test.rs
@@ -105,6 +105,10 @@ fn test_language_corpus(start_seed: usize, language_name: &str) {
 
     let log_seed = env::var("TREE_SITTER_LOG_SEED").is_ok();
 
+    if log_seed {
+        println!("  start seed: {}", start_seed);
+    }
+
     println!();
     for test in tests {
         println!("  {} example - {}", language_name, test.name);
diff --git a/cli/src/tests/helpers/fixtures.rs b/cli/src/tests/helpers/fixtures.rs
index 46c674cd..f790ed75 100644
--- a/cli/src/tests/helpers/fixtures.rs
+++ b/cli/src/tests/helpers/fixtures.rs
@@ -1,6 +1,6 @@
 use lazy_static::lazy_static;
-use std::fs;
 use std::path::{Path, PathBuf};
+use std::{env, fs};
 use tree_sitter::Language;
 use tree_sitter_highlight::HighlightConfiguration;
 use tree_sitter_loader::Loader;
@@ -9,7 +9,13 @@ use tree_sitter_tags::TagsConfiguration;
 include!("./dirs.rs");
 
 lazy_static! {
-    static ref TEST_LOADER: Loader = Loader::with_parser_lib_path(SCRATCH_DIR.clone());
+    static ref TEST_LOADER: Loader = {
+        let mut loader = Loader::with_parser_lib_path(SCRATCH_DIR.clone());
+        if env::var("TREE_SITTER_GRAMMAR_DEBUG").is_ok() {
+            loader.use_debug_build(true);
+        }
+        loader
+    };
 }
 
 pub fn test_loader<'a>() -> &'a Loader {