Rust errors / Types and traits
Rust compiler error · checked with rustc 1.99.0
Rust error E0800: cannot find type or const parameter `T` in this scope
What it meansA type or const parameter of the given name is not in scope.
What rustc prints
error[E0800]: cannot find type or const parameter `T` in this scope --> main.rs:1:34 | 1 | fn missing() -> impl Sized + use<T> {} | ^ not found in this scope | help: you might be missing a type parameter | 1 | fn missing<T>() -> impl Sized + use<T> {} | +++
Real output of rustc 1.99.0 compiling the official example below (2021 edition). Your names and line numbers will differ; the first line is the part to match.
E0800Types and traits
Activein rustc 1.99.0
8related errors linked below
The compiler team's explanation
A type or const parameter of the given name is not in scope.
Erroneous code examples:
fn missing() -> impl Sized + use<T> {}To fix this error, please verify you didn't misspell the type or const parameter, or double-check if you forgot to declare the parameter in the list of generics.
From rustc --explain E0800 (1.99.0), part of the Rust project, MIT or Apache-2.0. Official page.
Related errors
- E0308mismatched types
- E0277the trait bound is not satisfied
- E0599no method named X found in the current scope
- E0433failed to resolve
- E0792expected generic type parameter, found `u32`
- E0799expected type or const parameter, found function `main`
- E0801invalid generic `self` parameter type: `R`
- E0804cannot add auto trait `Send` to dyn bound via pointer cast
Up next
Often hit nextE0308: mismatched typesA related error from the same family.Read it next →Did this answer your question?