From e3c5bd617d040b5ee0bc79e6e7f01772adce791b Mon Sep 17 00:00:00 2001
From: Cormac Relf <web@cormacrelf.net>
Date: Tue, 15 Feb 2022 17:42:50 +1100
Subject: [PATCH 1/2] let-else: add a test for warnings on let-else with
 diverging tail

---
 src/test/ui/let-else/let-else-then-diverge.rs | 19 +++++++++++++++++++
 .../ui/let-else/let-else-then-diverge.stderr  | 14 ++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 src/test/ui/let-else/let-else-then-diverge.rs
 create mode 100644 src/test/ui/let-else/let-else-then-diverge.stderr

diff --git a/src/test/ui/let-else/let-else-then-diverge.rs b/src/test/ui/let-else/let-else-then-diverge.rs
new file mode 100644
index 0000000000000..49633d943beea
--- /dev/null
+++ b/src/test/ui/let-else/let-else-then-diverge.rs
@@ -0,0 +1,19 @@
+//
+// popped up in in #94012, where an alternative desugaring was
+// causing unreachable code errors
+
+#![feature(let_else)]
+#![deny(unused_variables)]
+#![deny(unreachable_code)]
+
+fn let_else_diverge() -> bool {
+    let Some(_) = Some("test") else {
+        let x = 5; //~ ERROR unused variable: `x`
+        return false;
+    };
+    return true;
+}
+
+fn main() {
+    let_else_diverge();
+}
diff --git a/src/test/ui/let-else/let-else-then-diverge.stderr b/src/test/ui/let-else/let-else-then-diverge.stderr
new file mode 100644
index 0000000000000..ceb61029d3863
--- /dev/null
+++ b/src/test/ui/let-else/let-else-then-diverge.stderr
@@ -0,0 +1,14 @@
+error: unused variable: `x`
+  --> $DIR/let-else-then-diverge.rs:11:13
+   |
+LL |         let x = 5;
+   |             ^ help: if this is intentional, prefix it with an underscore: `_x`
+   |
+note: the lint level is defined here
+  --> $DIR/let-else-then-diverge.rs:6:9
+   |
+LL | #![deny(unused_variables)]
+   |         ^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+

From 981852677c531d52f701b870bb27b45668a44d52 Mon Sep 17 00:00:00 2001
From: est31 <MTest31@outlook.com>
Date: Fri, 15 Jul 2022 18:53:23 +0200
Subject: [PATCH 2/2] Add regression test for #94176

---
 src/test/ui/let-else/issue-94176.rs     | 10 ++++++++++
 src/test/ui/let-else/issue-94176.stderr | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 src/test/ui/let-else/issue-94176.rs
 create mode 100644 src/test/ui/let-else/issue-94176.stderr

diff --git a/src/test/ui/let-else/issue-94176.rs b/src/test/ui/let-else/issue-94176.rs
new file mode 100644
index 0000000000000..e35bbd8883062
--- /dev/null
+++ b/src/test/ui/let-else/issue-94176.rs
@@ -0,0 +1,10 @@
+// Issue #94176: wrong span for the error message of a mismatched type error,
+// if the function uses a `let else` construct.
+#![feature(let_else)]
+
+pub fn test(a: Option<u32>) -> Option<u32> { //~ ERROR mismatched types
+    let Some(_) = a else { return None; };
+    println!("Foo");
+}
+
+fn main() {}
diff --git a/src/test/ui/let-else/issue-94176.stderr b/src/test/ui/let-else/issue-94176.stderr
new file mode 100644
index 0000000000000..0cb97aceebfd5
--- /dev/null
+++ b/src/test/ui/let-else/issue-94176.stderr
@@ -0,0 +1,19 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-94176.rs:5:32
+   |
+LL | pub fn test(a: Option<u32>) -> Option<u32> {
+   |        ----                    ^^^^^^^^^^^ expected enum `Option`, found `()`
+   |        |
+   |        implicitly returns `()` as its body has no tail or `return` expression
+   |
+   = note:   expected enum `Option<u32>`
+           found unit type `()`
+help: consider returning the local binding `a`
+   |
+LL ~     println!("Foo");
+LL +     a
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.