Fix E0317: Expected Named Type Error in Rust

Wed, 05 Aug 2026 12:44:04 +0800

1. Symptoms

When the Rust compiler encounters error E0317, you will see output similar to the following in your build:

error[E0317]: expected named type, found `%s`
  --> src/main.rs:12:5
   |
12 |     let value: SomeStruct = 42;
   |            ^^^^^^^^^^^^^^ expected struct, variant, or union type
   |
   = note: expected type `SomeStruct`
           found type `{integer}`

The error message specifically states that a “named type” was expected, meaning the compiler anticipated a struct, enum variant, or union type. Instead, it encountered a different kind of type such as a primitive, tuple, or function pointer. This error manifests most frequently in generic contexts where type constraints require a specific kind of named type, or when working with associated types that demand a struct-like definition.

Union on ErrorVault — Developer Error Code Dictionary

Fix E0317: Expected Named Type Error in Rust

1. Symptoms