Reduce nesting of items_after_statements workaround

Author: dtolnay

src/expand.rs

@@ -357,24 +357,25 @@ fn transform_block(context: Context, sig: &mut Signature, block: &mut Block) {
  }
 
  let stmts = &block.stmts;
- let stmts = if decls.is_empty() {
- quote!(#(#stmts)*)
- } else {
- quote!({ #(#stmts)* })
- };
  let let_ret = match &mut sig.output {
  ReturnType::Default => quote_spanned! {block.brace_token.span=>
- let _: () = { #(#decls)* #stmts };
+ #(#decls)*
+ let _: () = { #(#stmts)* };
  },
  ReturnType::Type(_, ret) => {
  if contains_associated_type_impl_trait(context, ret) {
- quote!(#(#decls)* #stmts)
+ if decls.is_empty() {
+ quote!(#(#stmts)*)
+ } else {
+ quote!(#(#decls)* { #(#stmts)* })
+ }
  } else {
  quote_spanned! {block.brace_token.span=>
  if let ::core::option::Option::Some(__ret) = ::core::option::Option::None::<#ret> {
  return __ret;
  }
- let __ret: #ret = { #(#decls)* #stmts };
+ #(#decls)*
+ let __ret: #ret = { #(#stmts)* };
  #[allow(unreachable_code)]
  __ret
  }