From 1b5fbe20768103ad6dd701314ceb0b57b3176474 Mon Sep 17 00:00:00 2001
From: b-naber <bn263@gmx.de>
Date: Wed, 23 Mar 2022 08:54:07 +0100
Subject: [PATCH] add test for treating ExprKind::ConstParam as temp

---
 src/test/ui/mir/thir-constparam-temp.rs     | 20 +++++++++++++++++++
 src/test/ui/mir/thir-constparam-temp.stderr | 22 +++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 src/test/ui/mir/thir-constparam-temp.rs
 create mode 100644 src/test/ui/mir/thir-constparam-temp.stderr

diff --git a/src/test/ui/mir/thir-constparam-temp.rs b/src/test/ui/mir/thir-constparam-temp.rs
new file mode 100644
index 00000000000..cdc5910b36c
--- /dev/null
+++ b/src/test/ui/mir/thir-constparam-temp.rs
@@ -0,0 +1,20 @@
+// build-pass
+
+#![feature(adt_const_params)]
+#![allow(incomplete_features)]
+
+#[derive(PartialEq, Eq)]
+struct Yikes;
+
+impl Yikes {
+    fn mut_self(&mut self) {}
+}
+
+fn foo<const YIKES: Yikes>() {
+    YIKES.mut_self()
+    //~^ WARNING taking a mutable reference
+}
+
+fn main() {
+    foo::<{ Yikes }>()
+}
diff --git a/src/test/ui/mir/thir-constparam-temp.stderr b/src/test/ui/mir/thir-constparam-temp.stderr
new file mode 100644
index 00000000000..297102e657e
--- /dev/null
+++ b/src/test/ui/mir/thir-constparam-temp.stderr
@@ -0,0 +1,22 @@
+warning: taking a mutable reference to a `const` item
+  --> $DIR/thir-constparam-temp.rs:14:5
+   |
+LL |     YIKES.mut_self()
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(const_item_mutation)]` on by default
+   = note: each usage of a `const` item creates a new temporary
+   = note: the mutable reference will refer to this temporary, not the original `const` item
+note: mutable reference created due to call to this method
+  --> $DIR/thir-constparam-temp.rs:10:5
+   |
+LL |     fn mut_self(&mut self) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+note: `const` item defined here
+  --> $DIR/thir-constparam-temp.rs:13:14
+   |
+LL | fn foo<const YIKES: Yikes>() {
+   |              ^^^^^
+
+warning: 1 warning emitted
+