Respect None-delimited group when parsing unary expr

src/expr.rs

@@ -1368,6 +1368,10 @@ pub(crate) mod parsing {
     fn unary_expr(input: ParseStream, allow_struct: AllowStruct) -> Result<Expr> {
         let begin = input.fork();
         let attrs = input.call(expr_attrs)?;
+        if input.peek(token::Group) {
+            return trailer_expr(begin, attrs, input, allow_struct);
+        }
+
         if input.peek(Token![&]) {
             let and_token: Token![&] = input.parse()?;
             let raw: Option<kw::raw> = if input.peek(kw::raw)

tests/test_expr.rs

@@ -216,6 +216,31 @@ fn test_macro_variable_struct() {
     "###);
 }
 
+#[test]
+fn test_macro_variable_unary() {
+    // mimics the token stream corresponding to `$expr.method()` where expr is `&self`
+    let inner = Group::new(Delimiter::None, quote!(&self));
+    let tokens = quote!(#inner.method());
+    snapshot!(tokens as Expr, @r###"
+    Expr::MethodCall {
+        receiver: Expr::Group {
+            expr: Expr::Reference {
+                expr: Expr::Path {
+                    path: Path {
+                        segments: [
+                            PathSegment {
+                                ident: "self",
+                            },
+                        ],
+                    },
+                },
+            },
+        },
+        method: "method",
+    }
+    "###);
+}
+
 #[test]
 fn test_macro_variable_match_arm() {
     // mimics the token stream corresponding to `match v { _ => $expr }`