1 files changed, 48 insertions, 0 deletions
diff --git a/tests/ui/parser/mut-patterns.rs b/tests/ui/parser/mut-patterns.rs
new file mode 100644
index 00000000000..8b83d6ab2f8
--- /dev/null
+++ b/tests/ui/parser/mut-patterns.rs
@@ -0,0 +1,48 @@
+// Can't put mut in non-ident pattern
+
+// edition:2018
+
+#![feature(box_patterns)]
+#![allow(warnings)]
+
+pub fn main() {
+    let mut _ = 0; //~ ERROR `mut` must be followed by a named binding
+    let mut (_, _) = (0, 0); //~ ERROR `mut` must be followed by a named binding
+
+    let mut (x @ y) = 0; //~ ERROR `mut` must be attached to each individual binding
+
+    let mut mut x = 0;
+    //~^ ERROR `mut` on a binding may not be repeated
+    //~| remove the additional `mut`s
+
+    struct Foo { x: isize }
+    let mut Foo { x: x } = Foo { x: 3 };
+    //~^ ERROR `mut` must be attached to each individual binding
+    //~| add `mut` to each binding
+
+    let mut Foo { x } = Foo { x: 3 };
+    //~^ ERROR `mut` must be attached to each individual binding
+    //~| add `mut` to each binding
+
+    struct r#yield(u8, u8);
+    let mut mut yield(become, await) = r#yield(0, 0);
+    //~^ ERROR `mut` on a binding may not be repeated
+    //~| ERROR `mut` must be attached to each individual binding
+    //~| ERROR expected identifier, found reserved keyword `yield`
+    //~| ERROR expected identifier, found reserved keyword `become`
+    //~| ERROR expected identifier, found keyword `await`
+
+    struct W<T, U>(T, U);
+    struct B { f: Box<u8> }
+    let mut W(mut a, W(b, W(ref c, W(d, B { box f }))))
+    //~^ ERROR `mut` must be attached to each individual binding
+        = W(0, W(1, W(2, W(3, B { f: Box::new(4u8) }))));
+
+    // Make sure we don't accidentally allow `mut $p` where `$p:pat`.
+    macro_rules! foo {
+        ($p:pat) => {
+            let mut $p = 0; //~ ERROR expected identifier, found `x`
+        }
+    }
+    foo!(x);
+}