error[E0277]: `main` has invalid return type `std::result::Result` --> $DIR/termination-trait-test-wrong-type.rs:6:1 | LL | / fn can_parse_zero_as_f32() -> Result { LL | | "0".parse() LL | | } | |_^ `main` can only return types that implement `Termination` | ::: $SRC_DIR/test/src/lib.rs:LL:COL | LL | pub fn assert_test_result(result: T) { | ----------- required by this bound in `assert_test_result` | = help: the trait `Termination` is not implemented for `std::result::Result` = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.