+ if generic_args.desugared_from_fn {
+ // First argument will be a tuple, which already includes the parentheses.
+ // If the tuple only contains 1 item, write it manually to avoid the trailing `,`.
+ if let hir_def::path::GenericArg::Type(TypeRef::Tuple(v)) =
+ &generic_args.args[0]
+ {
+ if v.len() == 1 {
+ write!(f, "(")?;
+ v[0].hir_fmt(f)?;
+ write!(f, ")")?;
+ } else {
+ generic_args.args[0].hir_fmt(f)?;
+ }
+ }
+ if let Some(ret) = &generic_args.bindings[0].type_ref {
+ if !matches!(ret, TypeRef::Tuple(v) if v.is_empty()) {
+ write!(f, " -> ")?;
+ ret.hir_fmt(f)?;
+ }
+ }
+ return Ok(());
+ }
+