diff --git a/full-tests/duplicate-self-ty-impls.rs b/full-tests/duplicate-self-ty-impls.rs
new file mode 100644
index 0000000..60ef88d
--- /dev/null
+++ b/full-tests/duplicate-self-ty-impls.rs
@@ -0,0 +1,16 @@
+trait A {}
+/// ~REQUIRE-DELETED trait-B
+trait B {}
+trait C {}
+
+/// ~MINIMIZE-ROOT impl-A
+impl A for () {}
+
+/// ~REQUIRE-DELETED impl-B
+impl B for () {}
+
+/// ~MINIMIZE-ROOT impl-C
+impl C for () {}
+
+/// ~MINIMIZE-ROOT main
+fn main() {}
diff --git a/tests/full_tests.rs b/tests/full_tests.rs
index 0cb4a2f..9b57ab2 100644
--- a/tests/full_tests.rs
+++ b/tests/full_tests.rs
@@ -97,6 +97,11 @@ fn setup_scripts(start_roots: &[String], proj_dir: &Path) -> Result<()> {
         write!(
             BufWriter::new(&file),
             r#"#!/usr/bin/env bash
+if ! cargo check ; then
+    >&2 echo "Cargo check failed"
+    exit 1
+fi
+
 OUT=$(rg -o "~MINIMIZE-ROOT [\w\-]*" --no-filename --sort path src)
 
 python3 -c "