Fix indentation for where clause in rustdoc pages

Author: GuillaumeGomez

src/librustdoc/html/format.rs

@@ -347,13 +347,19 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
             }
         } else {
             let mut br_with_padding = String::with_capacity(6 * indent + 28);
-            br_with_padding.push_str("\n");
+            br_with_padding.push('\n');
 
-            let padding_amount =
-                if ending == Ending::Newline { indent + 4 } else { indent + "fn where ".len() };
+            let where_indent = 3;
+            let padding_amount = if ending == Ending::Newline {
+                indent + 4
+            } else if indent == 0 {
+                4
+            } else {
+                indent + where_indent + "where ".len()
+            };
 
             for _ in 0..padding_amount {
-                br_with_padding.push_str(" ");
+                br_with_padding.push(' ');
             }
             let where_preds = where_preds.to_string().replace('\n', &br_with_padding);
 
@@ -370,7 +376,8 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
                     let where_preds = where_preds.replacen(&br_with_padding, " ", 1);
 
                     let mut clause = br_with_padding;
-                    clause.truncate(clause.len() - "where ".len());
+                    // +1 is for `\n`.
+                    clause.truncate(indent + 1 + where_indent);
 
                     write!(clause, "<span class=\"where\">where{where_preds}</span>")?;
                     clause

src/librustdoc/html/render/mod.rs

@@ -859,8 +859,8 @@ fn assoc_method(
     w.reserve(header_len + "<a href=\"\" class=\"fn\">{".len() + "</a>".len());
     write!(
         w,
-        "{indent}{vis}{constness}{asyncness}{unsafety}{defaultness}{abi}fn <a{href} class=\"fn\">{name}</a>\
-         {generics}{decl}{notable_traits}{where_clause}",
+        "{indent}{vis}{constness}{asyncness}{unsafety}{defaultness}{abi}fn \
+         <a{href} class=\"fn\">{name}</a>{generics}{decl}{notable_traits}{where_clause}",
         indent = indent_str,
         vis = vis,
         constness = constness,