Struct UserTypeProjections

pub struct UserTypeProjections {
    pub contents: Vec<(UserTypeProjection, Span)>,
}

A collection of projections into user types.

They are projections because a binding can occur a part of a parent pattern that has been ascribed a type.

It’s a collection because there can be multiple type ascriptions on the path from the root of the pattern down to the binding itself.

An example:

struct S<'a>((i32, &'a str), String);
let S((_, w): (i32, &'static str), _): S = ...;
//    ------  ^^^^^^^^^^^^^^^^^^^ (1)
//  ---------------------------------  ^ (2)

The highlights labelled (1) show the subpattern (_, w) being ascribed the type (i32, &'static str).

The highlights labelled (2) show the whole pattern being ascribed the type S.

In this example, when we descend to w, we will have built up the following two projected types:

• base: S, projection: (base.0).1
• base: (i32, &'static str), projection: base.1

The first will lead to the constraint w: &'1 str (for some inferred region '1). The second will lead to the constraint w: &'static str.

Fields

contents: Vec<(UserTypeProjection, Span)>