https://errorvault.dev/tags/e0661/ Recent content in E0661 on ErrorVault — Developer Error Code Dictionary Hugo en-us Tue, 28 Jul 2026 05:32:04 +0800 https://errorvault.dev/rust/rust-e0661-method-call-unsized-field/ Tue, 28 Jul 2026 05:32:04 +0800 https://errorvault.dev/rust/rust-e0661-method-call-unsized-field/ <h2 id="1-symptoms">1. Symptoms</h2> <p>The Rust compiler emits error E0661 when you attempt to invoke a method on a struct or enum field that has an unsized type. This error manifests during compilation and prevents the binary from being built, regardless of whether the method being called is defined on the field type or inherited through a trait implementation.</p> <p>The compiler produces output similar to the following when this error is encountered:</p>