Adding handling and tests for custom type with implemented expect method

Author: Donald Robertson

clippy_lints/src/methods.rs

@@ -1006,11 +1006,13 @@ fn lint_expect_fun_call(cx: &LateContext, expr: &hir::Expr, method_span: Span, n
             return;
         }
 
-        let self_ty = cx.tables.expr_ty(self_expr);
-        let closure = match match_type(cx, self_ty, &paths::OPTION) {
-            true => "||",
-            false => "|_|",
-        };
+        let self_type = cx.tables.expr_ty(self_expr);
+        let known_types = &[&paths::OPTION, &paths::RESULT];
+
+        // if not a known type, return early
+        if known_types.iter().all(|&k| !match_type(cx, self_type, k)) {
+            return;
+        }
 
         // don't lint for constant values
         let owner_def = cx.tcx.hir.get_parent_did(arg.id);
@@ -1019,6 +1021,11 @@ fn lint_expect_fun_call(cx: &LateContext, expr: &hir::Expr, method_span: Span, n
             return;
         }
 
+        let closure = match match_type(cx, self_type, &paths::OPTION) {
+            true => "||",
+            false => "|_|",
+        };
+
         let sugg: Cow<_> = snippet(cx, arg.span, "..");
         let span_replace_word = method_span.with_hi(span.hi());
 

tests/ui/methods.rs

@@ -344,6 +344,16 @@ fn or_fun_call() {
 
 /// Checks implementation of the `EXPECT_FUN_CALL` lint
 fn expect_fun_call() {
+    struct Foo;
+
+    impl Foo {
+        fn new() -> Self { Foo }
+
+        fn expect(&self, msg: &str) {
+            panic!("{}", msg)
+        }
+    }
+
     let with_some = Some("value");
     with_some.expect("error");
 
@@ -369,6 +379,15 @@ fn expect_fun_call() {
 
     let with_err_and_as_str: Result<(), ()> = Err(());
     with_err_and_as_str.expect(format!("Error {}: fake error", error_code).as_str());
+
+    let with_dummy_type = Foo::new();
+    with_dummy_type.expect("another test string");
+
+    let with_dummy_type_and_format = Foo::new();
+    with_dummy_type_and_format.expect(&format!("Error {}: fake error", error_code));
+
+    let with_dummy_type_and_as_str = Foo::new();
+    with_dummy_type_and_as_str.expect(format!("Error {}: fake error", error_code).as_str());
 }
 
 /// Checks implementation of `ITER_NTH` lint

tests/ui/methods.stderr

@@ -424,105 +424,105 @@ error: use of `unwrap_or` followed by a function call
     |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "".to_owned())`
 
 error: use of `expect` followed by a function call
-   --> $DIR/methods.rs:355:26
+   --> $DIR/methods.rs:365:26
     |
-355 |     with_none_and_format.expect(&format!("Error {}: fake error", error_code));
+365 |     with_none_and_format.expect(&format!("Error {}: fake error", error_code));
     |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| panic!(&format!("Error {}: fake error", error_code)))`
     |
     = note: `-D expect-fun-call` implied by `-D warnings`
 
 error: use of `expect` followed by a function call
-   --> $DIR/methods.rs:358:26
+   --> $DIR/methods.rs:368:26
     |
-358 |     with_none_and_as_str.expect(format!("Error {}: fake error", error_code).as_str());
+368 |     with_none_and_as_str.expect(format!("Error {}: fake error", error_code).as_str());
     |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| panic!(format!("Error {}: fake error", error_code).as_str()))`
 
 error: use of `expect` followed by a function call
-   --> $DIR/methods.rs:368:25
+   --> $DIR/methods.rs:378:25
     |
-368 |     with_err_and_format.expect(&format!("Error {}: fake error", error_code));
+378 |     with_err_and_format.expect(&format!("Error {}: fake error", error_code));
     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|_| panic!(&format!("Error {}: fake error", error_code)))`
 
 error: use of `expect` followed by a function call
-   --> $DIR/methods.rs:371:25
+   --> $DIR/methods.rs:381:25
     |
-371 |     with_err_and_as_str.expect(format!("Error {}: fake error", error_code).as_str());
+381 |     with_err_and_as_str.expect(format!("Error {}: fake error", error_code).as_str());
     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|_| panic!(format!("Error {}: fake error", error_code).as_str()))`
 
 error: called `.iter().nth()` on a Vec. Calling `.get()` is both faster and more readable
-   --> $DIR/methods.rs:382:23
+   --> $DIR/methods.rs:401:23
     |
-382 |         let bad_vec = some_vec.iter().nth(3);
+401 |         let bad_vec = some_vec.iter().nth(3);
     |                       ^^^^^^^^^^^^^^^^^^^^^^
     |
     = note: `-D iter-nth` implied by `-D warnings`
 
 error: called `.iter().nth()` on a slice. Calling `.get()` is both faster and more readable
-   --> $DIR/methods.rs:383:26
+   --> $DIR/methods.rs:402:26
     |
-383 |         let bad_slice = &some_vec[..].iter().nth(3);
+402 |         let bad_slice = &some_vec[..].iter().nth(3);
     |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `.iter().nth()` on a slice. Calling `.get()` is both faster and more readable
-   --> $DIR/methods.rs:384:31
+   --> $DIR/methods.rs:403:31
     |
-384 |         let bad_boxed_slice = boxed_slice.iter().nth(3);
+403 |         let bad_boxed_slice = boxed_slice.iter().nth(3);
     |                               ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `.iter().nth()` on a VecDeque. Calling `.get()` is both faster and more readable
-   --> $DIR/methods.rs:385:29
+   --> $DIR/methods.rs:404:29
     |
-385 |         let bad_vec_deque = some_vec_deque.iter().nth(3);
+404 |         let bad_vec_deque = some_vec_deque.iter().nth(3);
     |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `.iter_mut().nth()` on a Vec. Calling `.get_mut()` is both faster and more readable
-   --> $DIR/methods.rs:390:23
+   --> $DIR/methods.rs:409:23
     |
-390 |         let bad_vec = some_vec.iter_mut().nth(3);
+409 |         let bad_vec = some_vec.iter_mut().nth(3);
     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `.iter_mut().nth()` on a slice. Calling `.get_mut()` is both faster and more readable
-   --> $DIR/methods.rs:393:26
+   --> $DIR/methods.rs:412:26
     |
-393 |         let bad_slice = &some_vec[..].iter_mut().nth(3);
+412 |         let bad_slice = &some_vec[..].iter_mut().nth(3);
     |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `.iter_mut().nth()` on a VecDeque. Calling `.get_mut()` is both faster and more readable
-   --> $DIR/methods.rs:396:29
+   --> $DIR/methods.rs:415:29
     |
-396 |         let bad_vec_deque = some_vec_deque.iter_mut().nth(3);
+415 |         let bad_vec_deque = some_vec_deque.iter_mut().nth(3);
     |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-   --> $DIR/methods.rs:408:13
+   --> $DIR/methods.rs:427:13
     |
-408 |     let _ = some_vec.iter().skip(42).next();
+427 |     let _ = some_vec.iter().skip(42).next();
     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |
     = note: `-D iter-skip-next` implied by `-D warnings`
 
 error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-   --> $DIR/methods.rs:409:13
+   --> $DIR/methods.rs:428:13
     |
-409 |     let _ = some_vec.iter().cycle().skip(42).next();
+428 |     let _ = some_vec.iter().cycle().skip(42).next();
     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-   --> $DIR/methods.rs:410:13
+   --> $DIR/methods.rs:429:13
     |
-410 |     let _ = (1..10).skip(10).next();
+429 |     let _ = (1..10).skip(10).next();
     |             ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-   --> $DIR/methods.rs:411:14
+   --> $DIR/methods.rs:430:14
     |
-411 |     let _ = &some_vec[..].iter().skip(3).next();
+430 |     let _ = &some_vec[..].iter().skip(3).next();
     |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message
-   --> $DIR/methods.rs:420:13
+   --> $DIR/methods.rs:439:13
     |
-420 |     let _ = opt.unwrap();
+439 |     let _ = opt.unwrap();
     |             ^^^^^^^^^^^^
     |
     = note: `-D option-unwrap-used` implied by `-D warnings`