diff --git a/tracing-core/src/field.rs b/tracing-core/src/field.rs
index a134e0dc2f..2d6ec13cde 100644
--- a/tracing-core/src/field.rs
+++ b/tracing-core/src/field.rs
@@ -1102,8 +1102,9 @@ mod test {
     use crate::metadata::{Kind, Level, Metadata};
     use crate::stdlib::{borrow::ToOwned, string::String};
 
-    struct TestCallsite1;
-    static TEST_CALLSITE_1: TestCallsite1 = TestCallsite1;
+    // Make sure TEST_CALLSITE_* have non-zero size, so they can't be located at the same address.
+    struct TestCallsite1(u8);
+    static TEST_CALLSITE_1: TestCallsite1 = TestCallsite1(0);
     static TEST_META_1: Metadata<'static> = metadata! {
         name: "field_test1",
         target: module_path!(),
@@ -1123,8 +1124,8 @@ mod test {
         }
     }
 
-    struct TestCallsite2;
-    static TEST_CALLSITE_2: TestCallsite2 = TestCallsite2;
+    struct TestCallsite2(u8);
+    static TEST_CALLSITE_2: TestCallsite2 = TestCallsite2(0);
     static TEST_META_2: Metadata<'static> = metadata! {
         name: "field_test2",
         target: module_path!(),