wrong_self_conversion: don't mention ~_mut at the end in the message

Author: mgacek8

clippy_lints/src/methods/mod.rs

@@ -1954,13 +1954,32 @@ fn lint_wrong_self_convention<'tcx>(
         if !self_kinds.iter().any(|k| k.matches(cx, self_ty, first_arg_ty)) {
             let suggestion = {
                 if conventions.len() > 1 {
-                    let s = conventions
-                        .iter()
-                        .map(|c| format!("`{}`", &c.to_string()))
-                        .collect::<Vec<_>>()
-                        .join(" and ");
-
-                    format!("methods called like this: ({})", &s)
+                    let special_case = {
+                        // Don't mention `NotEndsWith` when there is also `StartsWith` convention present
+                        if conventions.len() == 2 {
+                            match conventions {
+                                [Convention::StartsWith(starts_with), Convention::NotEndsWith(_)]
+                                | [Convention::NotEndsWith(_), Convention::StartsWith(starts_with)] => {
+                                    Some(format!("methods called `{}`", Convention::StartsWith(starts_with)))
+                                },
+                                _ => None,
+                            }
+                        } else {
+                            None
+                        }
+                    };
+                    match special_case {
+                        Some(suggestion) => suggestion,
+                        None => {
+                            let s = conventions
+                                .iter()
+                                .map(|c| format!("`{}`", &c.to_string()))
+                                .collect::<Vec<_>>()
+                                .join(" and ");
+
+                            format!("methods called like this: ({})", &s)
+                        },
+                    }
                 } else {
                     format!("methods called `{}`", &conventions[0])
                 }

tests/ui/wrong_self_convention.stderr

@@ -30,7 +30,7 @@ error: methods called `is_*` usually take self by reference or no self; consider
 LL |     fn is_i32(self) {}
    |               ^^^^
 
-error: methods called like this: (`to_*` and `~_mut`) usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
   --> $DIR/wrong_self_convention.rs:42:15
    |
 LL |     fn to_i32(self) {}
@@ -60,7 +60,7 @@ error: methods called `is_*` usually take self by reference or no self; consider
 LL |     pub fn is_i64(self) {}
    |                   ^^^^
 
-error: methods called like this: (`to_*` and `~_mut`) usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
   --> $DIR/wrong_self_convention.rs:49:19
    |
 LL |     pub fn to_i64(self) {}
@@ -90,7 +90,7 @@ error: methods called `is_*` usually take self by reference or no self; consider
 LL |         fn is_i32(self) {}
    |                   ^^^^
 
-error: methods called like this: (`to_*` and `~_mut`) usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
   --> $DIR/wrong_self_convention.rs:102:19
    |
 LL |         fn to_i32(self) {}
@@ -120,7 +120,7 @@ error: methods called `is_*` usually take self by reference or no self; consider
 LL |         fn is_i32(self);
    |                   ^^^^
 
-error: methods called like this: (`to_*` and `~_mut`) usually take self by reference; consider choosing a less ambiguous name
+error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
   --> $DIR/wrong_self_convention.rs:126:19
    |
 LL |         fn to_i32(self);
@@ -144,7 +144,7 @@ error: methods called `from_*` usually take no self; consider choosing a less am
 LL |         fn from_i32(self);
    |                     ^^^^
 
-error: methods called like this: (`to_*` and `~_mut`) usually take self by reference; consider choosing a less ambiguous name
+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]> {