wrong_self_conversion: Emit lint msg with help msg

Author: mgacek8

clippy_lints/src/methods/mod.rs

@@ -1985,19 +1985,21 @@ fn lint_wrong_self_convention<'tcx>(
                 }
             };
 
-            span_lint(
+            span_lint_and_help(
                 cx,
                 lint,
                 first_arg_span,
                 &format!(
-                    "{} usually take {}; consider choosing a less ambiguous name",
+                    "{} usually take {}",
                     suggestion,
                     &self_kinds
                         .iter()
                         .map(|k| k.description())
                         .collect::<Vec<_>>()
                         .join(" or ")
                 ),
+                None,
+                "consider choosing a less ambiguous name",
             );
         }
     }

tests/ui/def_id_nocore.stderr

@@ -1,10 +1,11 @@
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take self by reference or self by mutable reference
   --> $DIR/def_id_nocore.rs:26:19
    |
 LL |     pub fn as_ref(self) -> &'static str {
    |                   ^^^^
    |
    = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
+   = help: consider choosing a less ambiguous name
 
 error: aborting due to previous error
 

tests/ui/wrong_self_convention.rs

@@ -163,28 +163,3 @@ mod issue6307 {
         fn to_mut(&mut self);
     }
 }
-
-mod issue6758 {
-    pub enum Test<T> {
-        One(T),
-        Many(Vec<T>),
-    }
-
-    impl<T> Test<T> {
-        // If a method starts with `to_` and not ends with `_mut` it should expect `&self`
-        pub fn to_many(&mut self) -> Option<&mut [T]> {
-            match self {
-                Self::Many(data) => Some(data),
-                _ => None,
-            }
-        }
-
-        // If a method starts with `to_` and ends with `_mut` it should expect `&mut self`
-        pub fn to_many_mut(&self) -> Option<&[T]> {
-            match self {
-                Self::Many(data) => Some(data),
-                _ => None,
-            }
-        }
-    }
-}

tests/ui/wrong_self_convention.stderr

@@ -1,160 +1,195 @@
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:18:17
    |
 LL |     fn from_i32(self) {}
    |                 ^^^^
    |
    = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:24:21
    |
 LL |     pub fn from_i64(self) {}
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take self by reference or self by mutable reference
   --> $DIR/wrong_self_convention.rs:36:15
    |
 LL |     fn as_i32(self) {}
    |               ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take self by value
   --> $DIR/wrong_self_convention.rs:38:17
    |
 LL |     fn into_i32(&self) {}
    |                 ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take self by reference or no self
   --> $DIR/wrong_self_convention.rs:40:15
    |
 LL |     fn is_i32(self) {}
    |               ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference
   --> $DIR/wrong_self_convention.rs:42:15
    |
 LL |     fn to_i32(self) {}
    |               ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:44:17
    |
 LL |     fn from_i32(self) {}
    |                 ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take self by reference or self by mutable reference
   --> $DIR/wrong_self_convention.rs:46:19
    |
 LL |     pub fn as_i64(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take self by value
   --> $DIR/wrong_self_convention.rs:47:21
    |
 LL |     pub fn into_i64(&self) {}
    |                     ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take self by reference or no self
   --> $DIR/wrong_self_convention.rs:48:19
    |
 LL |     pub fn is_i64(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference
   --> $DIR/wrong_self_convention.rs:49:19
    |
 LL |     pub fn to_i64(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:50:21
    |
 LL |     pub fn from_i64(self) {}
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take self by reference or self by mutable reference
   --> $DIR/wrong_self_convention.rs:95:19
    |
 LL |         fn as_i32(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take self by value
   --> $DIR/wrong_self_convention.rs:98:25
    |
 LL |         fn into_i32_ref(&self) {}
    |                         ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take self by reference or no self
   --> $DIR/wrong_self_convention.rs:100:19
    |
 LL |         fn is_i32(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference
   --> $DIR/wrong_self_convention.rs:102:19
    |
 LL |         fn to_i32(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:104:21
    |
 LL |         fn from_i32(self) {}
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take self by reference or self by mutable reference
   --> $DIR/wrong_self_convention.rs:119:19
    |
 LL |         fn as_i32(self);
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take self by value
   --> $DIR/wrong_self_convention.rs:122:25
    |
 LL |         fn into_i32_ref(&self);
    |                         ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take self by reference or no self
   --> $DIR/wrong_self_convention.rs:124:19
    |
 LL |         fn is_i32(self);
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference
   --> $DIR/wrong_self_convention.rs:126:19
    |
 LL |         fn to_i32(self);
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:128:21
    |
 LL |         fn from_i32(self);
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take self by value
   --> $DIR/wrong_self_convention.rs:146:25
    |
 LL |         fn into_i32_ref(&self);
    |                         ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no self
   --> $DIR/wrong_self_convention.rs:152:21
    |
 LL |         fn from_i32(self);
    |                     ^^^^
-
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
-  --> $DIR/wrong_self_convention.rs:175:24
-   |
-LL |         pub fn to_many(&mut self) -> Option<&mut [T]> {
-   |                        ^^^^^^^^^
-
-error: methods called like this: (`to_*` and `*_mut`) usually take self by mutable reference; consider choosing a less ambiguous name
-  --> $DIR/wrong_self_convention.rs:183:28
    |
-LL |         pub fn to_many_mut(&self) -> Option<&[T]> {
-   |                            ^^^^^
+   = help: consider choosing a less ambiguous name
 
-error: aborting due to 26 previous errors
+error: aborting due to 24 previous errors
 

tests/ui/wrong_self_conventions_mut.rs

@@ -0,0 +1,30 @@
+// edition:2018
+#![warn(clippy::wrong_self_convention)]
+#![allow(dead_code)]
+
+fn main() {}
+
+mod issue6758 {
+    pub enum Test<T> {
+        One(T),
+        Many(Vec<T>),
+    }
+
+    impl<T> Test<T> {
+        // If a method starts with `to_` and not ends with `_mut` it should expect `&self`
+        pub fn to_many(&mut self) -> Option<&mut [T]> {
+            match self {
+                Self::Many(data) => Some(data),
+                _ => None,
+            }
+        }
+
+        // If a method starts with `to_` and ends with `_mut` it should expect `&mut self`
+        pub fn to_many_mut(&self) -> Option<&[T]> {
+            match self {
+                Self::Many(data) => Some(data),
+                _ => None,
+            }
+        }
+    }
+}

tests/ui/wrong_self_conventions_mut.stderr

@@ -0,0 +1,19 @@
+error: methods called `to_*` usually take self by reference
+  --> $DIR/wrong_self_conventions_mut.rs:15:24
+   |
+LL |         pub fn to_many(&mut self) -> Option<&mut [T]> {
+   |                        ^^^^^^^^^
+   |
+   = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
+   = help: consider choosing a less ambiguous name
+
+error: methods called like this: (`to_*` and `*_mut`) usually take self by mutable reference
+  --> $DIR/wrong_self_conventions_mut.rs:23:28
+   |
+LL |         pub fn to_many_mut(&self) -> Option<&[T]> {
+   |                            ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
+
+error: aborting due to 2 previous errors
+