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diff --git a/src/test/ui/never_type/fallback-closure-ret.rs b/src/test/ui/never_type/fallback-closure-ret.rs
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+++ b/src/test/ui/never_type/fallback-closure-ret.rs
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+// This test verifies that never type fallback preserves the following code in a
+// compiling state. This pattern is fairly common in the wild, notably seen in
+// wasmtime v0.16. Typically this is some closure wrapper that expects a
+// collection of 'known' signatures, and -> ! is not included in that set.
+//
+// This test is specifically targeted by the unit type fallback when
+// encountering a set of obligations like `?T: Foo` and `Trait::Projection =
+// ?T`. In the code below, these are `R: Bar` and `Fn::Output = R`.
+//
+// revisions: nofallback fallback
+// check-pass
+
+#![cfg_attr(fallback, feature(never_type_fallback))]
+
+trait Bar { }
+impl Bar for () {  }
+impl Bar for u32 {  }
+
+fn foo<R: Bar>(_: impl Fn() -> R) {}
+
+fn main() {
+    foo(|| panic!());
+}