Unused assignment warning should trigger for structs #16789
Description
This code should ideally trigger warnings about unused assignments, but it doesn't.
struct Pos { x: i32 } fn foo() -> Pos{ Pos{x: 2} } fn main() { foo().x += 1; // Unused assignment let mut f = Pos { x: 2 }; f.x = 2; // Unused assignment }It could be useful in situations like this:
struct Property { x: i32 } struct Foo { prop: Property } impl Foo { fn prop(&self) -> Property { self.prop } fn mut_prop(&mut self) -> &mut Property { &mut self.prop } } fn main() { let mut foo = Foo{prop: Property{x: 2}}; foo.prop().x += 2; // Oops, accidentally called prop() instead of mut_prop() foo.mut_prop().x += 2; }