From de6b08a2b5b6afe3a8ff9e2e16a33265ddff9696 Mon Sep 17 00:00:00 2001
From: Jonas Platte <jplatte+git@posteo.de>
Date: Fri, 6 Sep 2024 19:11:51 +0200
Subject: [PATCH] macros: Simplify internal derive macro input parsing

---
 crates/ruma-macros/src/api/request.rs  | 12 ++++--------
 crates/ruma-macros/src/api/response.rs | 12 ++++--------
 crates/ruma-macros/src/lib.rs          |  4 ++--
 3 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/crates/ruma-macros/src/api/request.rs b/crates/ruma-macros/src/api/request.rs
index 733e6801..0d4bc0c0 100644
--- a/crates/ruma-macros/src/api/request.rs
+++ b/crates/ruma-macros/src/api/request.rs
@@ -3,7 +3,7 @@ use quote::{quote, ToTokens};
 use syn::{
     parse::{Parse, ParseStream},
     punctuated::Punctuated,
-    DeriveInput, Field, Generics, Ident, ItemStruct, Token, Type,
+    Field, Generics, Ident, ItemStruct, Token, Type,
 };
 
 use super::{
@@ -44,13 +44,9 @@ impl Parse for RequestAttr {
     }
 }
 
-pub fn expand_derive_request(input: DeriveInput) -> syn::Result<TokenStream> {
-    let fields = match input.data {
-        syn::Data::Struct(s) => s.fields,
-        _ => panic!("This derive macro only works on structs"),
-    };
-
-    let fields = fields.into_iter().map(RequestField::try_from).collect::<syn::Result<_>>()?;
+pub fn expand_derive_request(input: ItemStruct) -> syn::Result<TokenStream> {
+    let fields =
+        input.fields.into_iter().map(RequestField::try_from).collect::<syn::Result<_>>()?;
 
     let mut error_ty = None;
 
diff --git a/crates/ruma-macros/src/api/response.rs b/crates/ruma-macros/src/api/response.rs
index 66a77d6a..f6ea621b 100644
--- a/crates/ruma-macros/src/api/response.rs
+++ b/crates/ruma-macros/src/api/response.rs
@@ -6,7 +6,7 @@ use syn::{
     parse::{Parse, ParseStream},
     punctuated::Punctuated,
     visit::Visit,
-    DeriveInput, Field, Generics, Ident, ItemStruct, Lifetime, Token, Type,
+    Field, Generics, Ident, ItemStruct, Lifetime, Token, Type,
 };
 
 use super::{
@@ -59,13 +59,9 @@ impl Parse for ResponseAttr {
     }
 }
 
-pub fn expand_derive_response(input: DeriveInput) -> syn::Result<TokenStream> {
-    let fields = match input.data {
-        syn::Data::Struct(s) => s.fields,
-        _ => panic!("This derive macro only works on structs"),
-    };
-
-    let fields = fields.into_iter().map(ResponseField::try_from).collect::<syn::Result<_>>()?;
+pub fn expand_derive_response(input: ItemStruct) -> syn::Result<TokenStream> {
+    let fields =
+        input.fields.into_iter().map(ResponseField::try_from).collect::<syn::Result<_>>()?;
     let mut manual_body_serde = false;
     let mut error_ty = None;
     let mut status_ident = None;
diff --git a/crates/ruma-macros/src/lib.rs b/crates/ruma-macros/src/lib.rs
index 53d1c486..dda4a84a 100644
--- a/crates/ruma-macros/src/lib.rs
+++ b/crates/ruma-macros/src/lib.rs
@@ -397,14 +397,14 @@ pub fn response(attr: TokenStream, item: TokenStream) -> TokenStream {
 /// Internal helper that the request macro delegates most of its work to.
 #[proc_macro_derive(Request, attributes(ruma_api))]
 pub fn derive_request(input: TokenStream) -> TokenStream {
-    let input = parse_macro_input!(input as DeriveInput);
+    let input = parse_macro_input!(input);
     expand_derive_request(input).unwrap_or_else(syn::Error::into_compile_error).into()
 }
 
 /// Internal helper that the response macro delegates most of its work to.
 #[proc_macro_derive(Response, attributes(ruma_api))]
 pub fn derive_response(input: TokenStream) -> TokenStream {
-    let input = parse_macro_input!(input as DeriveInput);
+    let input = parse_macro_input!(input);
     expand_derive_response(input).unwrap_or_else(syn::Error::into_compile_error).into()
 }