rust/tests/ui/return/tail-expr-as-potential-return.rs

68 lines
1.5 KiB
Rust

//@ edition:2018
// > Suggest returning tail expressions that match return type
// >
// > Some newcomers are confused by the behavior of tail expressions,
// > interpreting that "leaving out the `;` makes it the return value".
// > To help them go in the right direction, suggest using return instead
// > when applicable.
// (original commit description for this test)
//
// This test was amended to also serve as a regression test for #92308, where
// this suggestion would not trigger with async functions.
fn main() {
}
fn foo(x: bool) -> Result<f64, i32> {
if x {
Err(42)
//~^ ERROR mismatched types
//~| HELP you might have meant to return this value
}
Ok(42.0)
}
async fn bar(x: bool) -> Result<f64, i32> {
if x {
Err(42)
//~^ ERROR mismatched types
//~| HELP you might have meant to return this value
}
Ok(42.0)
}
trait Identity {
type Out;
}
impl<T> Identity for T {
type Out = T;
}
async fn foo2() -> i32 {
if true {
1i32
//~^ ERROR mismatched types
//~| HELP you might have meant to return this value
}
0
}
struct Receiver;
impl Receiver {
fn generic<T>(self) -> Option<T> {
None
}
}
fn method() -> Option<i32> {
if true {
Receiver.generic();
//~^ ERROR type annotations needed
//~| HELP consider specifying the generic argument
//~| HELP you might have meant to return this to infer its type parameters
}
None
}