# Error code E0229

An associated type binding was done outside of the type parameter declaration and `where` clause.

Erroneous code example:

ⓘ

    pub trait Foo {
        type A;
        fn boo(&self) -> <Self as Foo>::A;
    }

    struct Bar;

    impl Foo for isize {
        type A = usize;
        fn boo(&self) -> usize { 42 }
    }

    fn baz<I>(x: &<I as Foo<A=Bar>>::A) {}
    // error: associated type bindings are not allowed here

Run

To solve this error, please move the type bindings in the type parameter declaration:

    fn baz<I: Foo<A=Bar>>(x: &<I as Foo>::A) {} // ok!

Run

Or in the `where` clause:

    fn baz<I>(x: &<I as Foo>::A) where I: Foo<A=Bar> {}

Run

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