error[E0308]: mismatched types --> $DIR/issue-35241.rs:3:20 | LL | struct Foo(u32); | ---------- `Foo` defines a struct constructor here, which should be called LL | LL | fn test() -> Foo { Foo } | --- ^^^ expected `Foo`, found struct constructor | | | expected `Foo` because of return type | = note: expected struct `Foo` found struct constructor `fn(u32) -> Foo {Foo}` help: use parentheses to construct this tuple struct | LL | fn test() -> Foo { Foo(/* u32 */) } | +++++++++++ error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.