Rust errors / Types and traits
Rust compiler error · checked with rustc 1.99.0
Rust error E0055: reached the recursion limit while auto-dereferencing `Foo`
What it meansDuring a method call, a value is automatically dereferenced as many times as needed to make the value's type match the method's receiver. The catch is that the compiler will only attempt to dereference a number of times up to the recursion limit (which can be set via the recursion_limit attribute).
What rustc prints
error[E0055]: reached the recursion limit while auto-dereferencing `Foo` --> main.rs:14:13 | 14 | ref_foo.foo(); | ^^^ deref recursion limit reached | = help: consider increasing the recursion limit by adding a `#![recursion_limit = "8"]` attribute to your crate (`main`)
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.
The compiler team's explanation
During a method call, a value is automatically dereferenced as many times as needed to make the value's type match the method's receiver. The catch is that the compiler will only attempt to dereference a number of times up to the recursion limit (which can be set via the recursion_limit attribute).
For a somewhat artificial example:
#![recursion_limit="4"]
struct Foo;
impl Foo {
fn foo(&self) {}
}
fn main() {
let foo = Foo;
let ref_foo = &&&&&Foo;
// error, reached the recursion limit while auto-dereferencing `&&&&&Foo`
ref_foo.foo();
}One fix may be to increase the recursion limit. Note that it is possible to create an infinite recursion of dereferencing, in which case the only fix is to somehow break the recursion.
From rustc --explain E0055 (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
- E0050method `foo` has 1 parameter but the declaration in trait `Foo::foo` has 2
- E0053method `foo` has an incompatible type for trait
- E0059type parameter to bare `FnOnce` trait must be a tuple
- E0069`return;` in a function whose return type is not `()`
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Often hit nextE0308: mismatched typesA related error from the same family.Read it next →Did this answer your question?