From 3d1f83efbd7227da1f259f071ab1af294df8d36e Mon Sep 17 00:00:00 2001 From: dswij Date: Tue, 1 Mar 2022 12:54:08 +0800 Subject: [PATCH] `map_identity` Add tests for needless `.map_err` --- tests/ui/map_identity.fixed | 2 ++ tests/ui/map_identity.rs | 2 ++ tests/ui/map_identity.stderr | 8 +++++++- 3 files changed, 11 insertions(+), 1 deletion(-) diff --git a/tests/ui/map_identity.fixed b/tests/ui/map_identity.fixed index 4a1452b25f3..2256e51f2d0 100644 --- a/tests/ui/map_identity.fixed +++ b/tests/ui/map_identity.fixed @@ -16,6 +16,8 @@ fn main() { let _: Result = Err(2.3).map(|x: i8| { return x + 3; }); + let _: Result = Ok(1); + let _: Result = Ok(1).map_err(|a: u32| a * 42); } fn not_identity(x: &u16) -> u16 { diff --git a/tests/ui/map_identity.rs b/tests/ui/map_identity.rs index 65c7e6e1ea5..ccfdc9ea76d 100644 --- a/tests/ui/map_identity.rs +++ b/tests/ui/map_identity.rs @@ -18,6 +18,8 @@ fn main() { let _: Result = Err(2.3).map(|x: i8| { return x + 3; }); + let _: Result = Ok(1).map_err(|a| a); + let _: Result = Ok(1).map_err(|a: u32| a * 42); } fn not_identity(x: &u16) -> u16 { diff --git a/tests/ui/map_identity.stderr b/tests/ui/map_identity.stderr index e4a0320cbda..b6a77281f6d 100644 --- a/tests/ui/map_identity.stderr +++ b/tests/ui/map_identity.stderr @@ -33,5 +33,11 @@ LL | | return x; LL | | }); | |______^ help: remove the call to `map` -error: aborting due to 5 previous errors +error: unnecessary map of the identity function + --> $DIR/map_identity.rs:21:36 + | +LL | let _: Result = Ok(1).map_err(|a| a); + | ^^^^^^^^^^^^^^^ help: remove the call to `map_err` + +error: aborting due to 6 previous errors