From dbadab54df148b55b2e884440bfaeaa38517e6e8 Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <spastorino@gmail.com>
Date: Tue, 24 Aug 2021 22:52:41 -0300
Subject: [PATCH] Add type of a let tait test impl trait straight in let

---
 .../type-alias-impl-trait/type_of_a_let2.rs   | 25 +++++++++++++++++++
 .../type_of_a_let2.stderr                     | 21 ++++++++++++++++
 2 files changed, 46 insertions(+)
 create mode 100644 src/test/ui/type-alias-impl-trait/type_of_a_let2.rs
 create mode 100644 src/test/ui/type-alias-impl-trait/type_of_a_let2.stderr

diff --git a/src/test/ui/type-alias-impl-trait/type_of_a_let2.rs b/src/test/ui/type-alias-impl-trait/type_of_a_let2.rs
new file mode 100644
index 00000000000..33d3f164ce1
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/type_of_a_let2.rs
@@ -0,0 +1,25 @@
+#![feature(type_alias_impl_trait)]
+#![allow(dead_code)]
+
+// FIXME This should be under a feature flag
+
+use std::fmt::Debug;
+
+fn foo1() -> u32 {
+    let x: impl Debug = 22_u32;
+    //~^ ERROR: `impl Trait` not allowed outside of function and method return types [E0562]
+    x // ERROR: we only know x: Debug, we don't know x = u32
+}
+
+fn foo2() -> u32 {
+    let x: impl Debug = 22_u32;
+    //~^ ERROR: `impl Trait` not allowed outside of function and method return types [E0562]
+    let y: impl Debug = x;
+    //~^ ERROR: `impl Trait` not allowed outside of function and method return types [E0562]
+    same_type((x, y)); // ERROR
+    x
+}
+
+fn same_type<T>(x: (T, T)) {}
+
+fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/type_of_a_let2.stderr b/src/test/ui/type-alias-impl-trait/type_of_a_let2.stderr
new file mode 100644
index 00000000000..7a1825a8e2d
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/type_of_a_let2.stderr
@@ -0,0 +1,21 @@
+error[E0562]: `impl Trait` not allowed outside of function and method return types
+  --> $DIR/type_of_a_let2.rs:9:12
+   |
+LL |     let x: impl Debug = 22_u32;
+   |            ^^^^^^^^^^
+
+error[E0562]: `impl Trait` not allowed outside of function and method return types
+  --> $DIR/type_of_a_let2.rs:15:12
+   |
+LL |     let x: impl Debug = 22_u32;
+   |            ^^^^^^^^^^
+
+error[E0562]: `impl Trait` not allowed outside of function and method return types
+  --> $DIR/type_of_a_let2.rs:17:12
+   |
+LL |     let y: impl Debug = x;
+   |            ^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0562`.