diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 5c8add5f3022..43507f17e355 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -831,32 +831,30 @@ declare_clippy_lint! { /// etc. instead. /// /// ### Why is this bad? - /// The function will always be called and potentially - /// allocate an object acting as the default. + /// The function will always be called. This is only bad if it allocates or + /// does some non-trivial amount of work. /// /// ### Known problems - /// If the function has side-effects, not calling it will - /// change the semantic of the program, but you shouldn't rely on that anyway. + /// If the function has side-effects, not calling it will change the + /// semantic of the program, but you shouldn't rely on that. + /// + /// The lint also cannot figure out whether the function you call is + /// actually expensive to call or not. /// /// ### Example /// ```rust /// # let foo = Some(String::new()); - /// foo.unwrap_or(String::new()); + /// foo.unwrap_or(String::from("empty")); /// ``` /// /// Use instead: /// ```rust /// # let foo = Some(String::new()); - /// foo.unwrap_or_else(String::new); - /// - /// // or - /// - /// # let foo = Some(String::new()); - /// foo.unwrap_or_default(); + /// foo.unwrap_or_else(|| String::from("empty")); /// ``` #[clippy::version = "pre 1.29.0"] pub OR_FUN_CALL, - perf, + nursery, "using any `*or` method with a function call, which suggests `*or_else`" } diff --git a/tests/ui/unwrap_or.rs b/tests/ui/unwrap_or.rs index bfb41e439473..a0c003f5b1ea 100644 --- a/tests/ui/unwrap_or.rs +++ b/tests/ui/unwrap_or.rs @@ -1,4 +1,4 @@ -#![warn(clippy::all)] +#![warn(clippy::all, clippy::or_fun_call)] fn main() { let s = Some(String::from("test string")).unwrap_or("Fail".to_string()).len();