diff --git a/pyo3-derive-backend/src/method.rs b/pyo3-derive-backend/src/method.rs
index f95fe820..9efe22d2 100644
--- a/pyo3-derive-backend/src/method.rs
+++ b/pyo3-derive-backend/src/method.rs
@@ -27,7 +27,7 @@ pub enum FnType {
     FnCall,
     FnClass,
     FnStatic,
-    PySelf(syn::TypePath),
+    PySelfNew(syn::TypeReference),
 }
 
 #[derive(Clone, PartialEq, Debug)]
@@ -103,13 +103,16 @@ impl<'a> FnSpec<'a> {
 
         if fn_type == FnType::Fn && !has_self {
             if arguments.is_empty() {
-                panic!("Static method needs #[staticmethod] attribute");
+                return Err(syn::Error::new_spanned(
+                    name,
+                    "Static method needs #[staticmethod] attribute",
+                ));
             }
             let tp = match arguments.remove(0).ty {
-                syn::Type::Path(p) => replace_self(p),
-                _ => panic!("Invalid type as self"),
+                syn::Type::Reference(r) => replace_self(r)?,
+                x => return Err(syn::Error::new_spanned(x, "Invalid type as custom self")),
             };
-            fn_type = FnType::PySelf(tp);
+            fn_type = FnType::PySelfNew(tp);
         }
 
         Ok(FnSpec {
@@ -386,15 +389,19 @@ fn parse_attributes(attrs: &mut Vec<syn::Attribute>) -> syn::Result<(FnType, Vec
     }
 }
 
-// Replace A<Self> with A<_>
-fn replace_self(path: &syn::TypePath) -> syn::TypePath {
+// Replace &A<Self> with &A<_>
+fn replace_self(refn: &syn::TypeReference) -> syn::Result<syn::TypeReference> {
     fn infer(span: proc_macro2::Span) -> syn::GenericArgument {
         syn::GenericArgument::Type(syn::Type::Infer(syn::TypeInfer {
             underscore_token: syn::token::Underscore { spans: [span] },
         }))
     }
-    let mut res = path.to_owned();
-    for seg in &mut res.path.segments {
+    let mut res = refn.to_owned();
+    let tp = match &mut *res.elem {
+        syn::Type::Path(p) => p,
+        _ => return Err(syn::Error::new_spanned(refn, "unsupported argument")),
+    };
+    for seg in &mut tp.path.segments {
         if let syn::PathArguments::AngleBracketed(ref mut g) = seg.arguments {
             let mut args = syn::punctuated::Punctuated::new();
             for arg in &g.args {
@@ -415,5 +422,6 @@ fn replace_self(path: &syn::TypePath) -> syn::TypePath {
             g.args = args;
         }
     }
-    res
+    res.lifetime = None;
+    Ok(res)
 }
diff --git a/pyo3-derive-backend/src/pymethod.rs b/pyo3-derive-backend/src/pymethod.rs
index 4d01f99c..e47edc04 100644
--- a/pyo3-derive-backend/src/pymethod.rs
+++ b/pyo3-derive-backend/src/pymethod.rs
@@ -34,7 +34,7 @@ pub fn gen_py_method(
     };
 
     let text_signature = match &spec.tp {
-        FnType::Fn | FnType::PySelf(_) | FnType::FnClass | FnType::FnStatic => {
+        FnType::Fn | FnType::PySelfNew(_) | FnType::FnClass | FnType::FnStatic => {
             utils::parse_text_signature_attrs(&mut *meth_attrs, name)?
         }
         FnType::FnNew => parse_erroneous_text_signature(
@@ -59,7 +59,7 @@ pub fn gen_py_method(
 
     Ok(match spec.tp {
         FnType::Fn => impl_py_method_def(name, doc, &spec, &impl_wrap(cls, name, &spec, true)),
-        FnType::PySelf(ref self_ty) => impl_py_method_def(
+        FnType::PySelfNew(ref self_ty) => impl_py_method_def(
             name,
             doc,
             &spec,
@@ -127,7 +127,7 @@ pub fn impl_wrap_pyslf(
     cls: &syn::Type,
     name: &syn::Ident,
     spec: &FnSpec<'_>,
-    self_ty: &syn::TypePath,
+    self_ty: &syn::TypeReference,
     noargs: bool,
 ) -> TokenStream {
     let names = get_arg_names(spec);
@@ -221,8 +221,7 @@ pub fn impl_proto_wrap(cls: &syn::Type, name: &syn::Ident, spec: &FnSpec<'_>) ->
 /// Generate class method wrapper (PyCFunction, PyCFunctionWithKeywords)
 pub fn impl_wrap_new(cls: &syn::Type, name: &syn::Ident, spec: &FnSpec<'_>) -> TokenStream {
     let names: Vec<syn::Ident> = get_arg_names(&spec);
-    let cb = quote! { #cls::#name(&_obj, #(#names),*) };
-
+    let cb = quote! { #cls::#name(#(#names),*) };
     let body = impl_arg_params(spec, cb);
 
     quote! {
@@ -240,11 +239,11 @@ pub fn impl_wrap_new(cls: &syn::Type, name: &syn::Ident, spec: &FnSpec<'_>) -> T
             let _args = _py.from_borrowed_ptr::<pyo3::types::PyTuple>(_args);
             let _kwargs: Option<&pyo3::types::PyDict> = _py.from_borrowed_ptr_or_opt(_kwargs);
 
-            #body
+            # body
 
-            match <<#cls as pyo3::PyTypeInfo>::ConcreteLayout as pyo3::pyclass::PyClassNew>::new(_py, _result) {
-                Ok(_slf) => _slf as _,
-                Err(e) => e.restore_and_null(),
+            match _result.and_then(|slf| pyo3::PyClassShell::new(_py, slf)) {
+                Ok(slf) => slf as _,
+                Err(e) => e.restore_and_null(_py),
             }
         }
     }