From fefd06dc02eea5c5bd96aedce17a5e58c8645f9a Mon Sep 17 00:00:00 2001
From: The 8472 <git@infinite-source.de>
Date: Fri, 15 Mar 2024 22:25:00 +0100
Subject: [PATCH] add test for #122301 to cover behavior that's on stable

if this ought to be broken it should at least happen intentionally
---
 .../control-flow/dead_branches_dont_eval.rs   | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 tests/ui/consts/control-flow/dead_branches_dont_eval.rs

diff --git a/tests/ui/consts/control-flow/dead_branches_dont_eval.rs b/tests/ui/consts/control-flow/dead_branches_dont_eval.rs
new file mode 100644
index 0000000000000..374349732f9ef
--- /dev/null
+++ b/tests/ui/consts/control-flow/dead_branches_dont_eval.rs
@@ -0,0 +1,46 @@
+//@ build-pass
+
+// issue 122301 - currently the only way to supress
+// const eval and codegen of code conditional on some other const
+
+struct Foo<T, const N: usize>(T);
+
+impl<T, const N: usize> Foo<T, N> {
+    const BAR: () = if N == 0 {
+        panic!()
+    };
+}
+
+struct Invoke<T, const N: usize>(T);
+
+impl<T, const N: usize> Invoke<T, N> {
+    const FUN: fn() = if N != 0 {
+        || Foo::<T, N>::BAR
+    } else {
+        || {}
+    };
+}
+
+// without closures
+
+struct S<T>(T);
+impl<T> S<T> {
+    const C: () = panic!();
+}
+
+const fn bar<T>() { S::<T>::C }
+
+struct ConstIf<T, const N: usize>(T);
+
+impl<T, const N: usize> ConstIf<T, N> {
+    const VAL: () = if N != 0 {
+        bar::<T>() // not called for N == 0, and hence not monomorphized
+    } else {
+        ()
+    };
+}
+
+fn main() {
+    let _val = Invoke::<(), 0>::FUN();
+    let _val = ConstIf::<(), 0>::VAL;
+}