Update syn to version 2

Author: surban

remoc_macro/Cargo.toml

@@ -12,7 +12,7 @@ license = "Apache-2.0"
 
 [dependencies]
 proc-macro2 = "1"
-syn = { version = "1", features = ["extra-traits", "full", "visit"] }
+syn = { version = "2", features = ["extra-traits", "full", "visit"] }
 quote = "1"
 
 

remoc_macro/src/lib.rs

@@ -3,7 +3,7 @@
 //! Procedural macros for Remoc.
 
 use quote::quote;
-use syn::{parse_macro_input, AttributeArgs};
+use syn::{meta, parse_macro_input};
 
 mod method;
 mod trait_def;
@@ -12,12 +12,10 @@ mod util;
 use crate::trait_def::TraitDef;
 
 #[proc_macro_attribute]
-pub fn remote(attr: proc_macro::TokenStream, input: proc_macro::TokenStream) -> proc_macro::TokenStream {
-    let attrs = parse_macro_input!(attr as AttributeArgs);
+pub fn remote(args: proc_macro::TokenStream, input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let mut trait_def = parse_macro_input!(input as TraitDef);
-    if let Err(err) = trait_def.apply_attrs(attrs) {
-        return err.into_compile_error().into();
-    }
+    let meta_parser = meta::parser(|meta| trait_def.parse_meta(meta));
+    parse_macro_input!(args with meta_parser);
 
     let vanilla_trait = trait_def.vanilla_trait();
     let request_enums = trait_def.request_enums();

remoc_macro/src/method.rs

@@ -76,7 +76,7 @@ impl Parse for TraitMethod {
         // Check for no_cancel attribute.
         let mut cancel = true;
         attrs.retain(|attr| {
-            if let Some(attr) = attr.path.get_ident() {
+            if let Some(attr) = attr.path().get_ident() {
                 if *attr == "no_cancel" {
                     cancel = false;
                     return false;
@@ -94,7 +94,7 @@ impl Parse for TraitMethod {
         // Parse arguments.
         let content;
         parenthesized!(content in input);
-        let raw_args: Punctuated<FnArg, Comma> = content.parse_terminated(FnArg::parse)?;
+        let raw_args: Punctuated<FnArg, Comma> = content.parse_terminated(FnArg::parse, Token![,])?;
 
         // Extract receiver and arguments.
         let mut self_ref = None;

remoc_macro/src/trait_def.rs

@@ -1,12 +1,12 @@
 //! Trait parsing and client and server generation.
 
-use proc_macro2::{Span, TokenStream};
+use proc_macro2::TokenStream;
 use quote::{format_ident, quote, TokenStreamExt};
 use syn::{
     braced,
+    meta::ParseNestedMeta,
     parse::{Parse, ParseStream},
-    Attribute, AttributeArgs, Error, GenericParam, Generics, Ident, Lifetime, LifetimeDef, Meta, NestedMeta,
-    Token, TypeParam, Visibility, WhereClause,
+    Attribute, GenericParam, Generics, Ident, Lifetime, LifetimeParam, Token, TypeParam, Visibility, WhereClause,
 };
 
 use crate::{
@@ -70,28 +70,17 @@ impl Parse for TraitDef {
 }
 
 impl TraitDef {
-    /// Applies attributes specified by the procedural macro invocation.
-    pub fn apply_attrs(&mut self, attrs: AttributeArgs) -> syn::Result<()> {
-        for attr in attrs {
-            if let NestedMeta::Meta(Meta::Path(path)) = attr {
-                if path.is_ident("clone") {
-                    if self.is_taking_value() {
-                        return Err(Error::new(
-                            Span::call_site(),
-                            "the client cannot be clonable if a method takes self by value",
-                        ));
-                    }
-                    self.clone = true;
-                } else {
-                    return Err(Error::new(
-                        Span::call_site(),
-                        format!("unknown attribute: {}", path.get_ident().unwrap()),
-                    ));
-                }
+    /// Parses and applies attributes specified by the procedural macro invocation.
+    pub fn parse_meta(&mut self, meta: ParseNestedMeta) -> syn::Result<()> {
+        if meta.path.is_ident("clone") {
+            if self.is_taking_value() {
+                return Err(meta.error("the client cannot be clonable if a method takes self by value"));
             }
+            self.clone = true;
+            Ok(())
+        } else {
+            Err(meta.error("unknown attribute"))
         }
-
-        Ok(())
     }
 
     /// True, if any trait method takes self by value.
@@ -167,7 +156,7 @@ impl TraitDef {
 
         if with_lifetime {
             let target_lt: Lifetime = syn::parse2(quote! {'target}).unwrap();
-            ty_generics.params.insert(0, LifetimeDef::new(target_lt).into());
+            ty_generics.params.insert(0, LifetimeParam::new(target_lt).into());
         }
 
         let mut impl_generics = ty_generics.clone();