Do not consider method call receiver as an argument in AST.

Author: cjgillot

src/chains.rs

@@ -145,7 +145,7 @@ impl ChainItemKind {
 
     fn from_ast(context: &RewriteContext<'_>, expr: &ast::Expr) -> (ChainItemKind, Span) {
         let (kind, span) = match expr.kind {
-            ast::ExprKind::MethodCall(ref segment, ref expressions, _) => {
+            ast::ExprKind::MethodCall(ref segment, ref receiver, ref expressions, _) => {
                 let types = if let Some(ref generic_args) = segment.args {
                     if let ast::GenericArgs::AngleBracketed(ref data) = **generic_args {
                         data.args
@@ -163,7 +163,7 @@ impl ChainItemKind {
                 } else {
                     vec![]
                 };
-                let span = mk_sp(expressions[0].span.hi(), expr.span.hi());
+                let span = mk_sp(receiver.span.hi(), expr.span.hi());
                 let kind = ChainItemKind::MethodCall(segment.clone(), types, expressions.clone());
                 (kind, span)
             }
@@ -253,7 +253,7 @@ impl ChainItem {
             format!("::<{}>", type_list.join(", "))
         };
         let callee_str = format!(".{}{}", rewrite_ident(context, method_name), type_str);
-        rewrite_call(context, &callee_str, &args[1..], span, shape)
+        rewrite_call(context, &callee_str, &args, span, shape)
     }
 }
 
@@ -400,8 +400,8 @@ impl Chain {
     // is a try! macro, we'll convert it to shorthand when the option is set.
     fn pop_expr_chain(expr: &ast::Expr, context: &RewriteContext<'_>) -> Option<ast::Expr> {
         match expr.kind {
-            ast::ExprKind::MethodCall(_, ref expressions, _) => {
-                Some(Self::convert_try(&expressions[0], context))
+            ast::ExprKind::MethodCall(_, ref receiver, _, _) => {
+                Some(Self::convert_try(&receiver, context))
             }
             ast::ExprKind::Field(ref subexpr, _)
             | ast::ExprKind::Try(ref subexpr)