rust/tests/ui/suggestions/chain-method-call-mutation-in-place.rs

fn main() {}
fn foo(mut s: String) -> String {
    s.push_str("asdf") //~ ERROR mismatched types
}
Add explanation for `&mut self` method call when expecting `-> Self` When a user tries to use a method as if it returned a new value of the same type as its receiver, we will emit a type error. Try to detect this and provide extra explanation that the method modifies the receiver in-place. This has confused people in the wild, like in https://users.rust-lang.org/t/newbie-why-the-commented-line-stops-the-snippet-from-compiling/47322 2020-08-16 18:33:30 -07:00			`fn main() {}`
			`fn foo(mut s: String) -> String {`
			`s.push_str("asdf") //~ ERROR mismatched types`
			`}`