1 error[E0308]: mismatched types
2 --> $DIR/issue-30225.rs:41:9
4 LL | u = v; // mark $0 and $1 in a subtype relationship
5 | ^ expected struct `A`, found struct `B`
7 = note: expected type `A`
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0308`.