Auto merge of #58927 - GuillaumeGomez:default-keyword, r=QuietMisdreavus

Add default keyword handling in rustdoc

Fixes #58898.

r? @QuietMisdreavus

src/librustdoc/html/format.rs

@@ -45,6 +45,7 @@ pub struct GenericBounds<'a>(pub &'a [clean::GenericBound]);
 /// Wrapper struct for emitting a comma-separated list of items
 pub struct CommaSep<'a, T>(pub &'a [T]);
 pub struct AbiSpace(pub Abi);
+pub struct DefaultSpace(pub bool);
 
 /// Wrapper struct for properly emitting a function or method declaration.
 pub struct Function<'a> {
@@ -1057,3 +1058,13 @@ impl fmt::Display for AbiSpace {
         }
     }
 }
+
+impl fmt::Display for DefaultSpace {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.0 {
+            write!(f, "default ")
+        } else {
+            Ok(())
+        }
+    }
+}

src/librustdoc/html/render.rs

@@ -61,7 +61,7 @@ use crate::doctree;
 use crate::fold::DocFolder;
 use crate::html::escape::Escape;
 use crate::html::format::{AsyncSpace, ConstnessSpace};
-use crate::html::format::{GenericBounds, WhereClause, href, AbiSpace};
+use crate::html::format::{GenericBounds, WhereClause, href, AbiSpace, DefaultSpace};
 use crate::html::format::{VisSpace, Function, UnsafetySpace, MutableSpace};
 use crate::html::format::fmt_impl_for_trait_page;
 use crate::html::item_type::ItemType;
@@ -3429,11 +3429,12 @@ fn render_assoc_item(w: &mut fmt::Formatter<'_>,
             }
         };
         let mut header_len = format!(
-            "{}{}{}{}{:#}fn {}{:#}",
+            "{}{}{}{}{}{:#}fn {}{:#}",
             VisSpace(&meth.visibility),
             ConstnessSpace(header.constness),
             UnsafetySpace(header.unsafety),
             AsyncSpace(header.asyncness),
+            DefaultSpace(meth.is_default()),
             AbiSpace(header.abi),
             name,
             *g
@@ -3445,12 +3446,13 @@ fn render_assoc_item(w: &mut fmt::Formatter<'_>,
             (0, true)
         };
         render_attributes(w, meth)?;
-        write!(w, "{}{}{}{}{}fn <a href='{href}' class='fnname'>{name}</a>\
+        write!(w, "{}{}{}{}{}{}fn <a href='{href}' class='fnname'>{name}</a>\
                    {generics}{decl}{where_clause}",
                VisSpace(&meth.visibility),
                ConstnessSpace(header.constness),
                UnsafetySpace(header.unsafety),
                AsyncSpace(header.asyncness),
+               DefaultSpace(meth.is_default()),
                AbiSpace(header.abi),
                href = href,
                name = name,