diff --git a/ptx/src/pass/test/insert_implicit_conversions/default_reg_b32_reg_f16x2.ptx b/ptx/src/pass/test/insert_implicit_conversions/default_reg_b32_reg_f16x2.ptx
new file mode 100644
index 0000000..e467734
--- /dev/null
+++ b/ptx/src/pass/test/insert_implicit_conversions/default_reg_b32_reg_f16x2.ptx
@@ -0,0 +1,22 @@
+.version 6.5
+.target sm_30
+.address_size 64
+
+.func (.reg .b32 output) default_reg_b32_reg_f16x2 (
+    .reg .f16x2  input
+)
+{
+    mov.b32 output, input;
+    ret;
+}
+
+// %%% output %%%
+
+.func (.reg .b32 %2) %1 (
+    .reg .f16x2 %3
+)
+{
+    .b32.reg %4 = zluda.convert_implicit.default.reg.b32.reg.f16x2 %3;
+    mov.b32 %2, %4;
+    ret;
+}
diff --git a/ptx/src/pass/test/insert_implicit_conversions/mod.rs b/ptx/src/pass/test/insert_implicit_conversions/mod.rs
index f758148..1fb7a54 100644
--- a/ptx/src/pass/test/insert_implicit_conversions/mod.rs
+++ b/ptx/src/pass/test/insert_implicit_conversions/mod.rs
@@ -20,3 +20,4 @@ fn run_insert_implicit_conversions(ptx: ptx_parser::Module) -> String {
 }
 
 test_insert_implicit_conversions!(default);
+test_insert_implicit_conversions!(default_reg_b32_reg_f16x2);
diff --git a/ptx/src/pass/test/mod.rs b/ptx/src/pass/test/mod.rs
index e54eed9..3a9ef1f 100644
--- a/ptx/src/pass/test/mod.rs
+++ b/ptx/src/pass/test/mod.rs
@@ -162,7 +162,7 @@ impl<'a> ast::VisitorMap<SpirvWord, SpirvWord, ()> for StatementFormatter<'a> {
         arg: SpirvWord,
         type_space: Option<(&ptx_parser::Type, ptx_parser::StateSpace)>,
         is_dst: bool,
-        relaxed_type_check: bool,
+        _relaxed_type_check: bool,
     ) -> Result<SpirvWord, ()> {
         if is_dst {
             if let Some(IdentEntry { name: None, .. }) = self.resolver.ident_map.get(&arg) {
@@ -205,7 +205,7 @@ fn statement_to_string(
         _ => todo!(),
     };
     let mut args_formatter = StatementFormatter::new(resolver);
-    stmt.visit_map(&mut args_formatter);
+    stmt.visit_map(&mut args_formatter).unwrap();
     args_formatter.format(&op)
 }
 
@@ -219,29 +219,40 @@ where
     F: FnOnce(ast::Module) -> D,
     D: std::fmt::Display,
 {
-    let actual_ptx_out = ast::parse_module_checked(ptx_in)
+    let (actual_ptx_out, errs) = ast::parse_module_checked(ptx_in)
         .map(|ast| {
             let result = run_pass(ast);
-            result.to_string()
+            (result.to_string(), vec![])
         })
-        .unwrap_or("".to_string());
+        .unwrap_or_else(|errs| ("".to_string(), errs));
+    for err in errs {
+        eprintln!("{}", err);
+    }
     compare_ptx(name, ptx_in, actual_ptx_out.trim(), expected_ptx_out);
     Ok(())
 }
 
 fn compare_ptx(name: &str, ptx_in: &str, actual_ptx_out: &str, expected_ptx_out: &str) {
     if actual_ptx_out != expected_ptx_out {
-        let output_dir = env::var("TEST_PTX_PASS_FAIL_DIR");
-        if let Ok(output_dir) = output_dir {
-            let output_dir = Path::new(&output_dir);
-            fs::create_dir_all(&output_dir).unwrap();
-            let output_file = output_dir.join(format!("{}.ptx", name));
-            let mut output_file = File::create(output_file).unwrap();
-            output_file.write_all(ptx_in.as_bytes()).unwrap();
-            output_file.write_all(b"\n\n// %%% output %%%\n\n").unwrap();
-            output_file.write_all(actual_ptx_out.as_bytes()).unwrap();
-        }
+        maybe_save_output(name, ptx_in, actual_ptx_out);
         let comparison = pretty_assertions::StrComparison::new(expected_ptx_out, actual_ptx_out);
         panic!("assertion failed: `(left == right)`\n\n{}", comparison);
     }
+    if actual_ptx_out == "" {
+        maybe_save_output(name, ptx_in, actual_ptx_out);
+        panic!("missing expected output");
+    }
+}
+
+fn maybe_save_output(name: &str, ptx_in: &str, actual_ptx_out: &str) {
+    let output_dir = env::var("TEST_PTX_PASS_FAIL_DIR");
+    if let Ok(output_dir) = output_dir {
+        let output_dir = Path::new(&output_dir);
+        fs::create_dir_all(&output_dir).unwrap();
+        let output_file = output_dir.join(format!("{}.ptx", name));
+        let mut output_file = File::create(output_file).unwrap();
+        output_file.write_all(ptx_in.as_bytes()).unwrap();
+        output_file.write_all(b"\n\n// %%% output %%%\n\n").unwrap();
+        output_file.write_all(actual_ptx_out.as_bytes()).unwrap();
+    }
 }