warning: unused return value of `need_to_use_this_value` that must be used --> $DIR/fn_must_use.rs:55:5 | LL | need_to_use_this_value(); | ^^^^^^^^^^^^^^^^^^^^^^^^^ | note: the lint level is defined here --> $DIR/fn_must_use.rs:3:9 | LL | #![warn(unused_must_use)] | ^^^^^^^^^^^^^^^ = note: it's important warning: unused return value of `MyStruct::need_to_use_this_method_value` that must be used --> $DIR/fn_must_use.rs:60:5 | LL | m.need_to_use_this_method_value(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: unused return value of `EvenNature::is_even` that must be used --> $DIR/fn_must_use.rs:61:5 | LL | m.is_even(); // trait method! | ^^^^^^^^^^^^ | = note: no side effects warning: unused return value of `MyStruct::need_to_use_this_associated_function_value` that must be used --> $DIR/fn_must_use.rs:64:5 | LL | MyStruct::need_to_use_this_associated_function_value(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: unused return value of `std::cmp::PartialEq::eq` that must be used --> $DIR/fn_must_use.rs:70:5 | LL | 2.eq(&3); | ^^^^^^^^^ warning: unused return value of `std::cmp::PartialEq::eq` that must be used --> $DIR/fn_must_use.rs:71:5 | LL | m.eq(&n); | ^^^^^^^^^ warning: unused comparison that must be used --> $DIR/fn_must_use.rs:74:5 | LL | 2 == 3; | ^^^^^^ warning: unused comparison that must be used --> $DIR/fn_must_use.rs:75:5 | LL | m == n; | ^^^^^^ warning: 8 warnings emitted