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diff --git a/src/test/ui/compile-fail-migration/cross-fn-cache-hole.rs b/src/test/ui/compile-fail-migration/cross-fn-cache-hole.rs
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+++ b/src/test/ui/compile-fail-migration/cross-fn-cache-hole.rs
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+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Check that when there are vacuous predicates in the environment
+// (which make a fn uncallable) we don't erroneously cache those and
+// then consider them satisfied elsewhere. The current technique for
+// doing this is to not use global caches when there is a chance that
+// the environment contains such a predicate.
+// We still error for `i32: Bar<u32>` pending #48214
+
+trait Foo<X,Y>: Bar<X> {
+}
+
+trait Bar<X> { }
+
+// We don't always check where clauses for sanity, but in this case
+// wfcheck does report an error here:
+fn vacuous<A>() //~ ERROR the trait bound `i32: Bar<u32>` is not satisfied
+    where i32: Foo<u32, A>
+{
+    // ... the original intention was to check that we don't use that
+    // vacuous where clause (which could never be satisfied) to accept
+    // the following line and then mess up calls elsewhere.
+    require::<i32, u32>();
+}
+
+fn require<A,B>()
+    where A: Bar<B>
+{
+}
+
+fn main() {
+    require::<i32, u32>();
+}