Fix unused code warnings in tests (using black_box)

Signed-off-by: Justus Flügel <[email protected]>

Author: JustusFluegel

tests/test_derive_attr.rs

@@ -159,6 +159,9 @@ fn transparent_generic() {
         Custom,
     }
 
+    std::hint::black_box(Combined::<i32>::Other(1));
+    std::hint::black_box(Combined::<i32>::Custom);
+
     assert_impl_diagnostic::<Combined<miette::MietteDiagnostic>>();
 }
 
@@ -260,6 +263,9 @@ fn generic_diagnostic_source() {
         Custom,
     }
 
+    std::hint::black_box(Combined::<i32>::Other(1));
+    std::hint::black_box(Combined::<i32>::Custom);
+
     assert_impl_diagnostic::<Combined<miette::MietteDiagnostic>>();
 }
 
@@ -273,5 +279,8 @@ fn generic_not_influencing_default() {
         Custom,
     }
 
+    std::hint::black_box(Combined::<i32>::Other(1));
+    std::hint::black_box(Combined::<i32>::Custom);
+
     assert_impl_diagnostic::<Combined<i32>>();
 }

tests/test_diagnostic_source_macro.rs

@@ -376,6 +376,7 @@ enum NestedEnumError {
     },
 }
 
+#[cfg(feature = "fancy-no-backtrace")]
 #[derive(Debug, miette::Diagnostic, thiserror::Error)]
 #[error("I am the inner error")]
 struct Case1Inner {