Add test for typo in or-pattern binding

Author: estebank

tests/ui/or-patterns/binding-typo.fixed

@@ -0,0 +1,26 @@
+// Issue #51976
+//@ run-rustfix
+#![deny(unused_variables)] //~ NOTE: the lint level is defined here
+enum Lol {
+    Foo,
+    Bar,
+}
+
+fn foo(x: (Lol, Lol)) {
+    use Lol::*;
+    match x {
+        (Foo, Bar) | (Bar, Foo) => {}
+        //~^ ERROR: variable `Ban` is not bound in all patterns
+        //~| HELP: you might have meant to use the similarly named previously used binding `Bar`
+        //~| NOTE: pattern doesn't bind `Ban`
+        //~| NOTE: variable not in all patterns
+        //~| ERROR: variable `Ban` is assigned to, but never used
+        //~| NOTE: consider using `_Ban` instead
+        _ => {}
+    }
+}
+
+fn main() {
+    use Lol::*;
+    foo((Foo, Bar));
+}

tests/ui/or-patterns/binding-typo.rs

@@ -0,0 +1,26 @@
+// Issue #51976
+//@ run-rustfix
+#![deny(unused_variables)] //~ NOTE: the lint level is defined here
+enum Lol {
+    Foo,
+    Bar,
+}
+
+fn foo(x: (Lol, Lol)) {
+    use Lol::*;
+    match x {
+        (Foo, Bar) | (Ban, Foo) => {}
+        //~^ ERROR: variable `Ban` is not bound in all patterns
+        //~| HELP: you might have meant to use the similarly named previously used binding `Bar`
+        //~| NOTE: pattern doesn't bind `Ban`
+        //~| NOTE: variable not in all patterns
+        //~| ERROR: variable `Ban` is assigned to, but never used
+        //~| NOTE: consider using `_Ban` instead
+        _ => {}
+    }
+}
+
+fn main() {
+    use Lol::*;
+    foo((Foo, Bar));
+}

tests/ui/or-patterns/binding-typo.stderr

@@ -0,0 +1,30 @@
+error[E0408]: variable `Ban` is not bound in all patterns
+  --> $DIR/binding-typo.rs:12:9
+   |
+LL |         (Foo, Bar) | (Ban, Foo) => {}
+   |         ^^^^^^^^^^    --- variable not in all patterns
+   |         |
+   |         pattern doesn't bind `Ban`
+   |
+help: you might have meant to use the similarly named previously used binding `Bar`
+   |
+LL -         (Foo, Bar) | (Ban, Foo) => {}
+LL +         (Foo, Bar) | (Bar, Foo) => {}
+   |
+
+error: variable `Ban` is assigned to, but never used
+  --> $DIR/binding-typo.rs:12:23
+   |
+LL |         (Foo, Bar) | (Ban, Foo) => {}
+   |                       ^^^
+   |
+   = note: consider using `_Ban` instead
+note: the lint level is defined here
+  --> $DIR/binding-typo.rs:3:9
+   |
+LL | #![deny(unused_variables)]
+   |         ^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0408`.