From d975ae502749fa41d460588be39314f19b77db5d Mon Sep 17 00:00:00 2001
From: Evan Merlock <evan@merlock.dev>
Date: Wed, 20 Sep 2023 18:53:07 -0500
Subject: [PATCH] test(const_eval): add test cases for #114994 - add new
 testcase for TypeVisitor on const-eval mutable ref check

---
 .../ui/consts/const-eval/issue-114994-fail.rs | 14 +++++++++++++
 .../const-eval/issue-114994-fail.stderr       | 21 +++++++++++++++++++
 tests/ui/consts/const-eval/issue-114994.rs    | 18 ++++++++++++++++
 3 files changed, 53 insertions(+)
 create mode 100644 tests/ui/consts/const-eval/issue-114994-fail.rs
 create mode 100644 tests/ui/consts/const-eval/issue-114994-fail.stderr
 create mode 100644 tests/ui/consts/const-eval/issue-114994.rs

diff --git a/tests/ui/consts/const-eval/issue-114994-fail.rs b/tests/ui/consts/const-eval/issue-114994-fail.rs
new file mode 100644
index 0000000000000..7235046409191
--- /dev/null
+++ b/tests/ui/consts/const-eval/issue-114994-fail.rs
@@ -0,0 +1,14 @@
+// This checks that function pointer signatures that are referenced mutably
+// but contain a &mut T parameter still fail in a constant context: see issue #114994.
+//
+// check-fail
+
+const fn use_mut_const_fn(_f: &mut fn(&mut String)) { //~ ERROR mutable references are not allowed in constant functions
+    ()
+}
+
+const fn use_mut_const_tuple_fn(_f: (fn(), &mut u32)) { //~ ERROR mutable references are not allowed in constant functions
+
+}
+
+fn main() {}
diff --git a/tests/ui/consts/const-eval/issue-114994-fail.stderr b/tests/ui/consts/const-eval/issue-114994-fail.stderr
new file mode 100644
index 0000000000000..4dae8ea9bcab3
--- /dev/null
+++ b/tests/ui/consts/const-eval/issue-114994-fail.stderr
@@ -0,0 +1,21 @@
+error[E0658]: mutable references are not allowed in constant functions
+  --> $DIR/issue-114994-fail.rs:6:27
+   |
+LL | const fn use_mut_const_fn(_f: &mut fn(&mut String)) {
+   |                           ^^
+   |
+   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
+   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
+
+error[E0658]: mutable references are not allowed in constant functions
+  --> $DIR/issue-114994-fail.rs:10:33
+   |
+LL | const fn use_mut_const_tuple_fn(_f: (fn(), &mut u32)) {
+   |                                 ^^
+   |
+   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
+   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/consts/const-eval/issue-114994.rs b/tests/ui/consts/const-eval/issue-114994.rs
new file mode 100644
index 0000000000000..a4cb2e61e5f6f
--- /dev/null
+++ b/tests/ui/consts/const-eval/issue-114994.rs
@@ -0,0 +1,18 @@
+// This checks that function pointer signatures containing &mut T types
+// work in a constant context: see issue #114994.
+//
+// check-pass
+
+const fn use_const_fn(_f: fn(&mut String)) {
+    ()
+}
+
+const fn get_some_fn() -> fn(&mut String) {
+    String::clear
+}
+
+const fn some_const_fn() {
+    let _f: fn(&mut String) = String::clear;
+}
+
+fn main() {}