Update syn to 2.0 (eupn#91)

Author: taiki-e

Cargo.toml

@@ -3,6 +3,7 @@ name = "macrotest"
 version = "1.0.9" # remember to update in lib.rs
 authors = ["eupn <[email protected]>"]
 edition = "2018"
+rust-version = "1.56"
 license = "MIT OR Apache-2.0"
 readme = "README.md"
 repository = "https://github.com/eupn/macrotest"
@@ -11,8 +12,8 @@ description = "Test harness for macro expansion"
 [dependencies]
 diff = "0.1"
 glob = "0.3"
-prettyplease = "0.1"
+prettyplease = "0.2"
 serde = { version = "1.0.105", features = ["derive"] }
 serde_json = "1.0"
-syn = { version = "1", features = ["full"] }
+syn = { version = "2", features = ["full"] }
 toml = "0.5"

README.md

@@ -2,14 +2,14 @@
 
 [![Travis-CI](https://api.travis-ci.com/eupn/macrotest.svg?branch=master)](https://travis-ci.com/eupn/macrotest)
 [![Crates.io](https://img.shields.io/crates/v/macrotest)](https://crates.io/crates/macrotest)
-![MSRV 1.34.0](https://img.shields.io/badge/MSRV-1.34.0-orange.svg)
+![MSRV 1.56](https://img.shields.io/badge/MSRV-1.56-orange.svg)
 [![docs.rs](https://docs.rs/macrotest/badge.svg)](https://docs.rs/macrotest/)
 [![Crates.io](https://img.shields.io/crates/d/macrotest)](https://crates.io/crates/macrotest)
 [![Crates.io](https://img.shields.io/crates/l/macrotest)](https://crates.io/crates/macrotest)
 
 Similar to [trybuild], but allows you to test how declarative or procedural macros are expanded.
 
-*Minimal Supported Rust Version: 1.34.0*
+*Minimal Supported Rust Version: 1.56*
 
 ----
 

src/expand.rs

@@ -12,7 +12,8 @@ use crate::manifest::{Bin, Build, Config, Manifest, Name, Package, Workspace};
 use crate::message::{message_different, message_expansion_error};
 use crate::rustflags;
 use crate::{error::Error, error::Result};
-use syn::{Item, Meta, NestedMeta};
+use syn::punctuated::Punctuated;
+use syn::{Item, Meta, Token};
 
 /// An extension for files containing `cargo expand` result.
 const EXPANDED_RS_SUFFIX: &str = "expanded.rs";
@@ -400,11 +401,17 @@ fn normalize_expansion(input: &[u8]) -> String {
     //     #![feature(prelude_import)]
     //
     syntax_tree.attrs.retain(|attr| {
-        if let Ok(Meta::List(meta)) = attr.parse_meta() {
-            if meta.path.is_ident("feature") && meta.nested.len() == 1 {
-                if let NestedMeta::Meta(Meta::Path(inner)) = &meta.nested[0] {
-                    if inner.is_ident("prelude_import") {
-                        return false;
+        if let Meta::List(meta) = &attr.meta {
+            if meta.path.is_ident("feature") {
+                if let Ok(list) =
+                    meta.parse_args_with(Punctuated::<Meta, Token![,]>::parse_terminated)
+                {
+                    if list.len() == 1 {
+                        if let Meta::Path(inner) = &list.first().unwrap() {
+                            if inner.is_ident("prelude_import") {
+                                return false;
+                            }
+                        }
                     }
                 }
             }
@@ -423,7 +430,7 @@ fn normalize_expansion(input: &[u8]) -> String {
     syntax_tree.items.retain(|item| {
         if let Item::Use(item) = item {
             if let Some(attr) = item.attrs.first() {
-                if attr.path.is_ident("prelude_import") && attr.tokens.is_empty() {
+                if attr.path().is_ident("prelude_import") && attr.meta.require_path_only().is_ok() {
                     return false;
                 }
             }

src/lib.rs

@@ -5,7 +5,7 @@
 //!
 //! Similar to [trybuild], but allows you to write tests on how macros are expanded.
 //!
-//! *Minimal Supported Rust Version: 1.34.0*
+//! *Minimal Supported Rust Version: 1.56*
 //!
 //! <br>
 //!

test-procmacro-project/Cargo.toml

@@ -10,7 +10,7 @@ proc-macro = true
 [dependencies]
 quote = "1"
 proc-macro2 = "1.0"
-syn = "1.0"
+syn = "2"
 
 [dev-dependencies]
 macrotest = { path = "../" }