Try to fix tests again

tests/structs/src/debug_derive_bad.c

@@ -10,6 +10,6 @@ typedef struct {
             } c;
         } b;
     } a;
-} S2;
+} StructWithUnion;
 
-S2 kS2;
+StructWithUnion kStructWithUnion;

tests/structs/src/debug_derive_good.c

@@ -6,13 +6,9 @@ typedef struct {
     int a;
 } S1;
 
-S1 kS1;
-
 typedef struct {
     va_list v;
-} S3;
+} S2;
 
-S3 get_struct_containing_va_list() {
-    S3 s;
-    return s;
-}
+S1 *kS1;
+S2 *kS2;

tests/structs/src/test_debug_derive_bad.rs

@@ -1,10 +1,10 @@
 //! xfail
 
 mod debug_derive_bad;
-use debug_derive_bad::rust_kS2;
+use debug_derive_bad::rust_kStructWithUnion;
 
 pub fn test_union() {
     unsafe {
-        format!("{rust_kS2:?}");
+        format!("{rust_kStructWithUnion:?}");
     }
 }

tests/structs/src/test_debug_derive_good.rs

@@ -1,16 +1,11 @@
-//! feature_c_variadic,
+//! feature_c_variadic
 
-use crate::debug_derive_good::{rust_kS1, rust_get_struct_containing_va_list};
+use crate::debug_derive_good::{rust_kS1, rust_kS2};
+use std::fmt::Debug;
 
-pub fn test_simple_struct() {
+pub fn test_debuggable() {
     unsafe {
-        format!("{rust_kS1:?}");
+        // Make sure each struct implements `Debug`
+        let _debuggable: Vec<*mut dyn Debug> = vec![rust_kS1, rust_kS2];
     }
 }
-
-pub fn test_struct_containing_va_list() {
-    unsafe {
-        let s = rust_get_struct_containing_va_list();
-        format!("{s:?}");
-    }
-}