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

compiler/rustc_ast/src/util/parser.rs

@@ -396,9 +396,9 @@ pub fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
             contains_exterior_struct_lit(&x)
         }
 
-        ast::ExprKind::MethodCall(.., ref exprs, _) => {
+        ast::ExprKind::MethodCall(_, ref receiver, _, _) => {
             // X { y: 1 }.bar(...)
-            contains_exterior_struct_lit(&exprs[0])
+            contains_exterior_struct_lit(&receiver)
         }
 
         _ => false,