Implement the lint for expect

Author: pksunkara

clippy_lints/src/methods/mod.rs

@@ -3658,10 +3658,15 @@ impl Methods {
                         case_sensitive_file_extension_comparisons::check(cx, expr, span, recv, arg);
                     }
                 },
-                ("expect", [_]) => match method_call(recv) {
-                    Some(("ok", recv, [], _, _)) => ok_expect::check(cx, expr, recv),
-                    Some(("err", recv, [], err_span, _)) => err_expect::check(cx, expr, recv, span, err_span, &self.msrv),
-                    _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests),
+                ("expect", [_]) => {
+                    match method_call(recv) {
+                        Some(("ok", recv, [], _, _)) => ok_expect::check(cx, expr, recv),
+                        Some(("err", recv, [], err_span, _)) => err_expect::check(cx, expr, recv, span, err_span, &self.msrv),
+                        _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests),
+                    }
+                    if let ExprKind::Call(recv, _) = recv.kind {
+                        unnecessary_literal_unwrap::check(cx, expr, recv, name);
+                    }
                 },
                 ("expect_err", [_]) => expect_used::check(cx, expr, recv, true, self.allow_expect_in_tests),
                 ("extend", [arg]) => {

tests/ui/unnecessary_literal_unwrap.stderr

@@ -7,5 +7,13 @@ LL |     let val = Some(1).unwrap();
    = help: 
    = note: `-D clippy::unnecessary-literal-unwrap` implied by `-D warnings`
 
-error: aborting due to previous error
+error: used `expect()` on `Some` value
+  --> $DIR/unnecessary_literal_unwrap.rs:5:15
+   |
+LL |     let val = Some(1).expect("this never happens");
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: 
+
+error: aborting due to 2 previous errors