Make it trim the contents

Author: Centri3

clippy_lints/src/four_forward_slashes.rs

@@ -54,24 +54,25 @@ impl<'tcx> LateLintPass<'tcx> for FourForwardSlashes {
             let Some(contents) = file.get_line(line) else {
                 continue;
             };
+            let contents = contents.trim();
             if contents.is_empty() {
                 break;
             }
             if contents.starts_with("////") {
                 let bounds = file.line_bounds(line);
                 let span = Span::new(bounds.start, bounds.end, SyntaxContext::root(), None);
 
-                if snippet_opt(cx, span).is_some_and(|s| s.starts_with("////")) {
+                if snippet_opt(cx, span).is_some_and(|s| s.trim().starts_with("////")) {
                     span_lint_and_sugg(
                         cx,
                         FOUR_FORWARD_SLASHES,
                         span,
                         "comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't",
                         "make this a doc comment by removing one `/`",
                         // It's a little unfortunate but the span includes the `\n` yet the contents
-                        // do not, so we must add it back. If some codebase uses `\r\n` instead this
-                        // they will need normalization but it should be fine
-                        contents[1..].to_owned() + "\n",
+                        // do not, so we must add it back. If some codebase uses `\r\n` instead they
+                        // will need normalization but it should be fine
+                        contents.replacen("////", "///", 1) + "\n",
                         Applicability::MachineApplicable,
                     );
                 }

tests/ui/four_forward_slashes.fixed

@@ -1,9 +1,11 @@
 //// first line borked doc comment. doesn't combust!
 //@run-rustfix
 //@aux-build:proc_macros.rs:proc-macro
+#![feature(custom_inner_attributes)]
 #![allow(unused)]
 #![warn(clippy::four_forward_slashes)]
 #![no_main]
+#![rustfmt::skip]
 
 #[macro_use]
 extern crate proc_macros;
@@ -27,6 +29,9 @@ fn d() {}
 #[allow(dead_code)]
 fn g() {}
 
+/// not very start of contents
+fn h() {}
+
 external! {
     //// don't lint me bozo
     fn e() {}

tests/ui/four_forward_slashes.rs

@@ -1,9 +1,11 @@
 //// first line borked doc comment. doesn't combust!
 //@run-rustfix
 //@aux-build:proc_macros.rs:proc-macro
+#![feature(custom_inner_attributes)]
 #![allow(unused)]
 #![warn(clippy::four_forward_slashes)]
 #![no_main]
+#![rustfmt::skip]
 
 #[macro_use]
 extern crate proc_macros;
@@ -27,6 +29,9 @@ fn d() {}
 #[allow(dead_code)]
 fn g() {}
 
+    //// not very start of contents
+fn h() {}
+
 external! {
     //// don't lint me bozo
     fn e() {}

tests/ui/four_forward_slashes.stderr

@@ -1,5 +1,5 @@
 error: comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't
-  --> $DIR/four_forward_slashes.rs:11:1
+  --> $DIR/four_forward_slashes.rs:13:1
    |
 LL | / //// whoops
 LL | | fn a() {}
@@ -12,7 +12,7 @@ LL + /// whoops
    |
 
 error: comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't
-  --> $DIR/four_forward_slashes.rs:14:1
+  --> $DIR/four_forward_slashes.rs:16:1
    |
 LL | / //// whoops
 LL | | #[allow(dead_code)]
@@ -24,7 +24,7 @@ LL + /// whoops
    |
 
 error: comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't
-  --> $DIR/four_forward_slashes.rs:19:1
+  --> $DIR/four_forward_slashes.rs:21:1
    |
 LL | / //// two borked comments!
 LL | | #[track_caller]
@@ -36,7 +36,7 @@ LL + /// two borked comments!
    |
 
 error: comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't
-  --> $DIR/four_forward_slashes.rs:18:1
+  --> $DIR/four_forward_slashes.rs:20:1
    |
 LL | / //// whoops
 LL | | //// two borked comments!
@@ -48,7 +48,7 @@ LL + /// whoops
    |
 
 error: comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't
-  --> $DIR/four_forward_slashes.rs:26:1
+  --> $DIR/four_forward_slashes.rs:28:1
    |
 LL | / //// between attributes
 LL | | #[allow(dead_code)]
@@ -59,5 +59,17 @@ help: make this a doc comment by removing one `/`
 LL + /// between attributes
    |
 
-error: aborting due to 5 previous errors
+error: comment with 4 forward slashes (`////`). This looks like a doc comment, but it isn't
+  --> $DIR/four_forward_slashes.rs:32:1
+   |
+LL | /     //// not very start of contents
+LL | | fn h() {}
+   | |_
+   |
+help: make this a doc comment by removing one `/`
+   |
+LL + /// not very start of contents
+   |
+
+error: aborting due to 6 previous errors