Improve error handling in proc-macros, handle DispatchError etc. (#123)

* Improve error handling.

* Fix build.

* Handle runtime errors.

* Add runtime trait for better type inference.

* Use runtime trait part 1.

* wip

* Add support for sudo.

* Finish error handling.

* Fix tests.

* Fix clippy warnings.

proc-macro/src/module.rs

@@ -17,6 +17,7 @@
 use crate::utils;
 use heck::SnakeCase;
 use proc_macro2::TokenStream;
+use proc_macro_error::abort;
 use quote::{
     format_ident,
     quote,
@@ -48,8 +49,10 @@ type ModuleAttrs = utils::Attrs<ModuleAttr>;
 fn ignore(attrs: &[syn::Attribute]) -> bool {
     for attr in attrs {
         if let Some(ident) = attr.path.get_ident() {
-            if ident.to_string() == "module" {
-                let attrs: ModuleAttrs = syn::parse2(attr.tokens.clone()).unwrap();
+            if ident == "module" {
+                let attrs: ModuleAttrs = syn::parse2(attr.tokens.clone())
+                    .map_err(|err| abort!("{}", err))
+                    .unwrap();
                 if !attrs.attrs.is_empty() {
                     return true
                 }
@@ -69,10 +72,12 @@ fn with_module_ident(module: &syn::Ident) -> syn::Ident {
 
 pub fn module(_args: TokenStream, tokens: TokenStream) -> TokenStream {
     let input: Result<syn::ItemTrait, _> = syn::parse2(tokens.clone());
-    if input.is_err() {
+    let input = if let Ok(input) = input {
+        input
+    } else {
+        // handle #[module(ignore)] by just returning the tokens
         return tokens
-    }
-    let input = input.unwrap();
+    };
 
     let subxt = utils::use_crate("substrate-subxt");
     let module = &input.ident;