Fix Rust E0529: Range Syntax Is Reserved But Only Allowed With a Feature Gate

Wed, 10 Jun 2026 19:56:04 +0800

1. Symptoms

When compiling Rust code, you encounter the following error:

error[E0529]: range syntax is reserved but only allowed with a feature gate
  --> src/main.rs:3:14
   |
3  |     let x = 1..10;
   |              ^^ reserved syntax
   |
   = note: the syntax is only stable when using a feature gate, which can be
     enabled with `#![feature(range_inclusive_steps)]` or similar

The error manifests with the .. range operator appearing in your code, often while working on Rust 2015 edition or when experimenting with experimental range features. The Rust compiler explicitly states that the range syntax is “reserved” and not available without the appropriate feature flag.

Rust 2015 on ErrorVault — Developer Error Code Dictionary

Fix Rust E0529: Range Syntax Is Reserved But Only Allowed With a Feature Gate

1. Symptoms