Use lowercase in error messages

clippy_lints/src/functions.rs

@@ -197,16 +197,16 @@ declare_clippy_lint! {
     /// struct EndOfStream;
     ///
     /// impl fmt::Display for EndOfStream {
-    /// 	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///			write!(f, "End of Stream")
-    /// 	}
+    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         write!(f, "End of Stream")
+    ///     }
     /// }
     ///
     /// impl std::error::Error for EndOfStream { }
     ///
     /// pub fn read_u8() -> Result<u8, EndOfStream> { Err(EndOfStream) }
     ///# fn main() {
-    ///# 	read_u8().unwrap();
+    ///#     read_u8().unwrap();
     ///# }
     /// ```
     ///
@@ -483,9 +483,9 @@ fn check_result_unit_err(cx: &LateContext<'_>, decl: &hir::FnDecl<'_>, item_span
                 cx,
                 RESULT_UNIT_ERR,
                 fn_header_span,
-                "This returns a `Result<_, ()>",
+                "this returns a `Result<_, ()>",
                 None,
-                "Use a custom Error type instead",
+                "use a custom Error type instead",
             );
         }
     }

tests/ui/result_unit_error.stderr

@@ -1,35 +1,35 @@
-error: This returns a `Result<_, ()>
+error: this returns a `Result<_, ()>
   --> $DIR/result_unit_error.rs:4:1
    |
 LL | pub fn returns_unit_error() -> Result<u32, ()> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::result-unit-err` implied by `-D warnings`
-   = help: Use a custom Error type instead
+   = help: use a custom Error type instead
 
-error: This returns a `Result<_, ()>
+error: this returns a `Result<_, ()>
   --> $DIR/result_unit_error.rs:13:5
    |
 LL |     fn get_that_error(&self) -> Result<bool, ()>;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: Use a custom Error type instead
+   = help: use a custom Error type instead
 
-error: This returns a `Result<_, ()>
+error: this returns a `Result<_, ()>
   --> $DIR/result_unit_error.rs:15:5
    |
 LL |     fn get_this_one_too(&self) -> Result<bool, ()> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: Use a custom Error type instead
+   = help: use a custom Error type instead
 
-error: This returns a `Result<_, ()>
+error: this returns a `Result<_, ()>
   --> $DIR/result_unit_error.rs:33:5
    |
 LL |     pub fn unit_error(&self) -> Result<usize, ()> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: Use a custom Error type instead
+   = help: use a custom Error type instead
 
 error: aborting due to 4 previous errors