Revert "do not force comments to be indented with a comment trailing a line of code (rust-lang#3833)"

This reverts commit fb01dc8.

Author: topecongiro

src/missed_spans.rs

@@ -3,7 +3,6 @@ use syntax::source_map::{BytePos, Pos, Span};
 use crate::comment::{is_last_comment_block, rewrite_comment, CodeCharKind, CommentCodeSlices};
 use crate::config::file_lines::FileLines;
 use crate::config::FileName;
-use crate::config::Version;
 use crate::coverage::transform_missing_snippet;
 use crate::shape::{Indent, Shape};
 use crate::source_map::LineRangeUtils;
@@ -234,7 +233,6 @@ impl<'a> FmtVisitor<'a> {
             .next();
 
         let fix_indent = last_char.map_or(true, |rev_c| ['{', '\n'].contains(&rev_c));
-        let mut on_same_line = false;
 
         let comment_indent = if fix_indent {
             if let Some('{') = last_char {
@@ -243,13 +241,6 @@ impl<'a> FmtVisitor<'a> {
             let indent_str = self.block_indent.to_string(self.config);
             self.push_str(&indent_str);
             self.block_indent
-        } else if self.config.version() == Version::Two && !snippet.starts_with('\n') {
-            // The comment appears on the same line as the previous formatted code.
-            // Assuming that comment is logically associated with that code, we want to keep it on
-            // the same level and avoid mixing it with possible other comment.
-            on_same_line = true;
-            self.push_str(" ");
-            self.block_indent
         } else {
             self.push_str(" ");
             Indent::from_width(self.config, last_line_width(&self.buffer))
@@ -260,34 +251,9 @@ impl<'a> FmtVisitor<'a> {
             self.config.max_width() - self.block_indent.width(),
         );
         let comment_shape = Shape::legacy(comment_width, comment_indent);
-
-        if on_same_line {
-            match subslice.find("\n") {
-                None => {
-                    self.push_str(subslice);
-                }
-                Some(offset) if offset + 1 == subslice.len() => {
-                    self.push_str(&subslice[..offset]);
-                }
-                Some(offset) => {
-                    // keep first line as is: if it were too long and wrapped, it may get mixed
-                    // with the other lines.
-                    let first_line = &subslice[..offset];
-                    self.push_str(first_line);
-                    self.push_str(&comment_indent.to_string_with_newline(self.config));
-
-                    let other_lines = &subslice[offset + 1..];
-                    let comment_str =
-                        rewrite_comment(other_lines, false, comment_shape, self.config)
-                            .unwrap_or_else(|| String::from(other_lines));
-                    self.push_str(&comment_str);
-                }
-            }
-        } else {
-            let comment_str = rewrite_comment(subslice, false, comment_shape, self.config)
-                .unwrap_or_else(|| String::from(subslice));
-            self.push_str(&comment_str);
-        }
+        let comment_str = rewrite_comment(subslice, false, comment_shape, self.config)
+            .unwrap_or_else(|| String::from(subslice));
+        self.push_str(&comment_str);
 
         status.last_wspace = None;
         status.line_start = offset + subslice.len();

src/utils.rs

@@ -193,13 +193,13 @@ pub(crate) fn is_attributes_extendable(attrs_str: &str) -> bool {
     !attrs_str.contains('\n') && !last_line_contains_single_line_comment(attrs_str)
 }
 
-/// The width of the first line in s.
+// The width of the first line in s.
 #[inline]
 pub(crate) fn first_line_width(s: &str) -> usize {
     unicode_str_width(s.splitn(2, '\n').next().unwrap_or(""))
 }
 
-/// The width of the last line in s.
+// The width of the last line in s.
 #[inline]
 pub(crate) fn last_line_width(s: &str) -> usize {
     unicode_str_width(s.rsplitn(2, '\n').next().unwrap_or(""))

src/visitor.rs

@@ -6,7 +6,6 @@ use syntax::{ast, visit};
 
 use crate::attr::*;
 use crate::comment::{rewrite_comment, CodeCharKind, CommentCodeSlices};
-use crate::config::Version;
 use crate::config::{BraceStyle, Config};
 use crate::coverage::transform_missing_snippet;
 use crate::items::{
@@ -292,35 +291,13 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                                 }
                             }
                         }
-                    } else {
-                        let sub_slice = sub_slice.trim();
-                        if comment_on_same_line {
-                            // 1 = a space before `//`
-                            let offset_len = 1 + last_line_width(&self.buffer)
-                                .saturating_sub(self.block_indent.width());
-                            match comment_shape
-                                .visual_indent(offset_len)
-                                .sub_width(offset_len)
-                            {
-                                Some(shp) => comment_shape = shp,
-                                None => comment_on_same_line = false,
-                            }
-                        };
-
-                        if comment_on_same_line {
-                            self.push_str(" ");
-                        } else {
-                            if count_newlines(snippet_in_between) >= 2 || extra_newline {
-                                self.push_str("\n");
-                            }
-                            self.push_str(&self.block_indent.to_string_with_newline(config));
-                        }
+                        self.push_str(&self.block_indent.to_string_with_newline(config));
+                    }
 
-                        let comment_str = rewrite_comment(&sub_slice, false, comment_shape, config);
-                        match comment_str {
-                            Some(ref s) => self.push_str(s),
-                            None => self.push_str(&sub_slice),
-                        }
+                    let comment_str = rewrite_comment(&sub_slice, false, comment_shape, config);
+                    match comment_str {
+                        Some(ref s) => self.push_str(s),
+                        None => self.push_str(&sub_slice),
                     }
                 }
                 CodeCharKind::Normal if skip_normal(&sub_slice) => {