Auto merge of #33600 - ollie27:rustdoc_impl_params, r=alexcrichton

rustdoc: Fix missing type parameters on impls

They were broken by #32558.

Fixes: #33592

src/librustdoc/clean/mod.rs

@@ -1534,13 +1534,6 @@ impl Type {
         }
     }
 
-    pub fn trait_name(&self) -> Option<String> {
-        match *self {
-            ResolvedPath { ref path, .. } => Some(path.last_name()),
-            _ => None,
-        }
-    }
-
     pub fn is_generic(&self) -> bool {
         match *self {
             ResolvedPath { is_generic, .. } => is_generic,

src/librustdoc/html/format.rs

@@ -587,7 +587,13 @@ fn fmt_impl(i: &clean::Impl, f: &mut fmt::Formatter, link_trait: bool) -> fmt::R
         if link_trait {
             write!(f, "{}", *ty)?;
         } else {
-            write!(f, "{}", ty.trait_name().unwrap())?;
+            match *ty {
+                clean::ResolvedPath{ typarams: None, ref path, is_generic: false, .. } => {
+                    let last = path.segments.last().unwrap();
+                    write!(f, "{}{}", last.name, last.params)?;
+                }
+                _ => unreachable!(),
+            }
         }
         write!(f, " for ")?;
     }