Feature gate

2 files changed, 125 insertions, 0 deletions

diff --git a/tests/ui/pattern/mut-ref-mut-2021.rs b/tests/ui/pattern/mut-ref-mut-2021.rs
new file mode 100644
index 00000000000..a3be40faeff
--- /dev/null
+++ b/tests/ui/pattern/mut-ref-mut-2021.rs
@@ -0,0 +1,55 @@
+//@ edition: 2021
+#![allow(incomplete_features)]
+#![feature(mut_ref)]
+
+struct Foo(u8);
+
+fn main() {
+    let Foo(a) = Foo(0);
+    a = 42; //~ ERROR [E0384]
+
+    let Foo(mut a) = Foo(0);
+    a = 42;
+
+    let Foo(ref a) = Foo(0);
+    a = &42; //~ ERROR [E0384]
+
+    let Foo(mut ref a) = Foo(0);
+    a = &42;
+
+    let Foo(ref mut a) = Foo(0);
+    a = &mut 42; //~ ERROR [E0384]
+
+    let Foo(mut ref mut a) = Foo(0);
+    a = &mut 42;
+
+    let Foo(a) = &Foo(0);
+    a = &42; //~ ERROR [E0384]
+
+    let Foo(mut a) = &Foo(0);
+    a = 42;
+
+    let Foo(ref a) = &Foo(0);
+    a = &42; //~ ERROR [E0384]
+
+    let Foo(mut ref a) = &Foo(0);
+    a = &42;
+
+    let Foo(a) = &mut Foo(0);
+    a = &mut 42; //~ ERROR [E0384]
+
+    let Foo(mut a) = &mut Foo(0);
+    a = 42;
+
+    let Foo(ref a) = &mut Foo(0);
+    a = &42; //~ ERROR [E0384]
+
+    let Foo(mut ref a) = &mut Foo(0);
+    a = &42;
+
+    let Foo(ref mut a) = &mut Foo(0);
+    a = &mut 42; //~ ERROR [E0384]
+
+    let Foo(mut ref mut a) = &mut Foo(0);
+    a = &mut 42;
+}
diff --git a/tests/ui/pattern/mut-ref-mut-2021.stderr b/tests/ui/pattern/mut-ref-mut-2021.stderr
new file mode 100644
index 00000000000..eb31ffa0e30
--- /dev/null
+++ b/tests/ui/pattern/mut-ref-mut-2021.stderr
@@ -0,0 +1,70 @@
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:9:5
+   |
+LL |     let Foo(a) = Foo(0);
+   |             -
+   |             |
+   |             first assignment to `a`
+   |             help: consider making this binding mutable: `mut a`
+LL |     a = 42;
+   |     ^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:15:5
+   |
+LL |     let Foo(ref a) = Foo(0);
+   |             ----- first assignment to `a`
+LL |     a = &42;
+   |     ^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:21:5
+   |
+LL |     let Foo(ref mut a) = Foo(0);
+   |             --------- first assignment to `a`
+LL |     a = &mut 42;
+   |     ^^^^^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:27:5
+   |
+LL |     let Foo(a) = &Foo(0);
+   |             - first assignment to `a`
+LL |     a = &42;
+   |     ^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:33:5
+   |
+LL |     let Foo(ref a) = &Foo(0);
+   |             ----- first assignment to `a`
+LL |     a = &42;
+   |     ^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:39:5
+   |
+LL |     let Foo(a) = &mut Foo(0);
+   |             - first assignment to `a`
+LL |     a = &mut 42;
+   |     ^^^^^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:45:5
+   |
+LL |     let Foo(ref a) = &mut Foo(0);
+   |             ----- first assignment to `a`
+LL |     a = &42;
+   |     ^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `a`
+  --> $DIR/mut-ref-mut-2021.rs:51:5
+   |
+LL |     let Foo(ref mut a) = &mut Foo(0);
+   |             --------- first assignment to `a`
+LL |     a = &mut 42;
+   |     ^^^^^^^^^^^ cannot assign twice to immutable variable
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0384`.