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diff --git a/src/test/ui/issues/issue-87199.rs b/src/test/ui/issues/issue-87199.rs
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+++ b/src/test/ui/issues/issue-87199.rs
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+// Regression test for issue #87199, where attempting to relax a bound
+// other than the only supported `?Sized` would still cause the compiler
+// to assume that the `Sized` bound was relaxed.
+
+// check-fail
+
+// Check that these function definitions only emit warnings, not errors
+fn arg<T: ?Send>(_: T) {}
+//~^ warning: default bound relaxed for a type parameter, but this does nothing
+fn ref_arg<T: ?Send>(_: &T) {}
+//~^ warning: default bound relaxed for a type parameter, but this does nothing
+fn ret() -> impl Iterator<Item = ()> + ?Send { std::iter::empty() }
+//~^ warning: default bound relaxed for a type parameter, but this does nothing
+
+// Check that there's no `?Sized` relaxation!
+fn main() {
+    ref_arg::<i32>(&5);
+    ref_arg::<[i32]>(&[5]);
+    //~^ the size for values of type `[i32]` cannot be known
+}