2 files changed, 34 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs b/tests/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs
new file mode 100644
index 000000000..1e20a5460
--- /dev/null
+++ b/tests/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs
@@ -0,0 +1,18 @@
+// revisions: default miropt
+//[miropt]compile-flags: -Z mir-opt-level=3
+// ~^ This flag is for #77668, it used to be ICE.
+
+#![crate_type = "lib"]
+
+pub fn bar<P>( // Error won't happen if "bar" is not generic
+    _baz: P,
+) {
+    hide_foo()();
+}
+
+fn hide_foo() -> impl Fn() { // Error won't happen if "iterate" hasn't impl Trait or has generics
+    foo
+}
+
+fn foo() { // Error won't happen if "foo" isn't used in "iterate" or has generics
+}
diff --git a/tests/ui/issues/issue-50865-private-impl-trait/main.rs b/tests/ui/issues/issue-50865-private-impl-trait/main.rs
new file mode 100644
index 000000000..16dfac53a
--- /dev/null
+++ b/tests/ui/issues/issue-50865-private-impl-trait/main.rs
@@ -0,0 +1,16 @@
+// run-pass
+// aux-build:lib.rs
+
+// Regression test for #50865.
+// When using generics or specifying the type directly, this example
+// codegens `foo` internally. However, when using a private `impl Trait`
+// function which references another private item, `foo` (in this case)
+// wouldn't be codegenned until main.rs used `bar`, as with impl Trait
+// it is not cast to `fn()` automatically to satisfy e.g.
+// `fn foo() -> fn() { ... }`.
+
+extern crate lib;
+
+fn main() {
+    lib::bar(()); // Error won't happen if bar is called from same crate
+}