add tests

src/test/ui/suggestions/match-ergonomics.rs

@@ -0,0 +1,40 @@
+fn main() {
+    let x = vec![1i32];
+    match &x[..] {
+        [&v] => {}, //~ ERROR mismatched types
+        _ => {},
+    }
+    match x {
+        [&v] => {}, //~ ERROR expected an array or slice
+        _ => {},
+    }
+    match &x[..] {
+        [v] => {},
+        _ => {},
+    }
+    match &x[..] {
+        &[v] => {},
+        _ => {},
+    }
+    match x {
+        [v] => {}, //~ ERROR expected an array or slice
+        _ => {},
+    }
+    let y = 1i32;
+    match &y {
+        &v => {},
+        _ => {},
+    }
+    match y {
+        &v => {}, //~ ERROR mismatched types
+        _ => {},
+    }
+    match &y {
+        v => {},
+        _ => {},
+    }
+    match y {
+        v => {},
+        _ => {},
+    }
+}

src/test/ui/suggestions/match-ergonomics.stderr

@@ -0,0 +1,41 @@
+error[E0308]: mismatched types
+  --> $DIR/match-ergonomics.rs:4:10
+   |
+LL |         [&v] => {},
+   |          ^^
+   |          |
+   |          expected i32, found reference
+   |          help: you can probaly remove the explicit borrow: `v`
+   |
+   = note: expected type `i32`
+              found type `&_`
+
+error[E0529]: expected an array or slice, found `std::vec::Vec<i32>`
+  --> $DIR/match-ergonomics.rs:8:9
+   |
+LL |         [&v] => {},
+   |         ^^^^ pattern cannot match with input type `std::vec::Vec<i32>`
+
+error[E0529]: expected an array or slice, found `std::vec::Vec<i32>`
+  --> $DIR/match-ergonomics.rs:20:9
+   |
+LL |         [v] => {},
+   |         ^^^ pattern cannot match with input type `std::vec::Vec<i32>`
+
+error[E0308]: mismatched types
+  --> $DIR/match-ergonomics.rs:29:9
+   |
+LL |         &v => {},
+   |         ^^ expected i32, found reference
+   |
+   = note: expected type `i32`
+              found type `&_`
+help: you can rely on match ergonomics and remove the explicit borrow
+   |
+LL |         v => {},
+   |         ^
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0308, E0529.
+For more information about an error, try `rustc --explain E0308`.