| pub struct Nullable<T: NotNull>(T); |
| |
| pub trait NotNull {} |
| |
| pub trait IntoNullable { |
| type Nullable; |
| } |
| |
| impl<T: NotNull> IntoNullable for T { |
| type Nullable = Nullable<T>; |
| } |
| |
| impl<T: NotNull> IntoNullable for Nullable<T> { |
| type Nullable = Nullable<T>; |
| } |
| |
| pub trait Expression { |
| type SqlType; |
| } |
| |
| pub trait Column: Expression {} |
| |
| #[derive(Debug, Copy, Clone)] |
| //~^ ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied |
| pub enum ColumnInsertValue<Col, Expr> where |
| Col: Column, |
| Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, |
| { |
| Expression(Col, Expr), |
| Default(Col), |
| } |
| |
| fn main() {} |
