Introduce `#![feature(bindings_after_at)]`.

Under the gate, `x @ Some(y)` is allowed.
This is subject to various restrictions for soundness.

4 files changed, 15 insertions, 38 deletions

diff --git a/src/test/ui/error-codes/E0007.rs b/src/test/ui/error-codes/E0007.rs
index cdda735ba44..4f7fc0dc232 100644
--- a/src/test/ui/error-codes/E0007.rs
+++ b/src/test/ui/error-codes/E0007.rs
@@ -1,9 +1,11 @@
+#![feature(bindings_after_at)]
+//~^ WARN the feature `bindings_after_at` is incomplete and may cause the compiler to crash
+
 fn main() {
     let x = Some("s".to_string());
     match x {
         op_string @ Some(s) => {},
         //~^ ERROR E0007
-        //~| ERROR E0303
         //~| ERROR E0382
         None => {},
     }
diff --git a/src/test/ui/error-codes/E0007.stderr b/src/test/ui/error-codes/E0007.stderr
index 89a6298c875..d7b8050c3a4 100644
--- a/src/test/ui/error-codes/E0007.stderr
+++ b/src/test/ui/error-codes/E0007.stderr
@@ -1,17 +1,19 @@
-error[E0007]: cannot bind by-move with sub-bindings
-  --> $DIR/E0007.rs:4:9
+warning: the feature `bindings_after_at` is incomplete and may cause the compiler to crash
+  --> $DIR/E0007.rs:1:12
    |
-LL |         op_string @ Some(s) => {},
-   |         ^^^^^^^^^^^^^^^^^^^ binds an already bound by-move value by moving it
+LL | #![feature(bindings_after_at)]
+   |            ^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
 
-error[E0303]: pattern bindings are not allowed after an `@`
-  --> $DIR/E0007.rs:4:26
+error[E0007]: cannot bind by-move with sub-bindings
+  --> $DIR/E0007.rs:7:9
    |
 LL |         op_string @ Some(s) => {},
-   |                          ^ not allowed after `@`
+   |         ^^^^^^^^^^^^^^^^^^^ binds an already bound by-move value by moving it
 
 error[E0382]: use of moved value
-  --> $DIR/E0007.rs:4:26
+  --> $DIR/E0007.rs:7:26
    |
 LL |     let x = Some("s".to_string());
    |         - move occurs because `x` has type `std::option::Option<std::string::String>`, which does not implement the `Copy` trait
@@ -22,7 +24,7 @@ LL |         op_string @ Some(s) => {},
    |         |                value used here after move
    |         value moved here
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0007, E0303, E0382.
+Some errors have detailed explanations: E0007, E0382.
 For more information about an error, try `rustc --explain E0007`.
diff --git a/src/test/ui/error-codes/E0303.rs b/src/test/ui/error-codes/E0303.rs
deleted file mode 100644
index 0530d43b653..00000000000
--- a/src/test/ui/error-codes/E0303.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-fn main() {
-    match Some("hi".to_string()) {
-        ref op_string_ref @ Some(s) => {},
-        //~^ ERROR pattern bindings are not allowed after an `@` [E0303]
-        //~| ERROR E0009
-        None => {},
-    }
-}
diff --git a/src/test/ui/error-codes/E0303.stderr b/src/test/ui/error-codes/E0303.stderr
deleted file mode 100644
index af537ce5625..00000000000
--- a/src/test/ui/error-codes/E0303.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error[E0009]: cannot bind by-move and by-ref in the same pattern
-  --> $DIR/E0303.rs:3:34
-   |
-LL |         ref op_string_ref @ Some(s) => {},
-   |         -------------------------^-
-   |         |                        |
-   |         |                        by-move pattern here
-   |         both by-ref and by-move used
-
-error[E0303]: pattern bindings are not allowed after an `@`
-  --> $DIR/E0303.rs:3:34
-   |
-LL |         ref op_string_ref @ Some(s) => {},
-   |                                  ^ not allowed after `@`
-
-error: aborting due to 2 previous errors
-
-Some errors have detailed explanations: E0009, E0303.
-For more information about an error, try `rustc --explain E0009`.