error: `impl` item signature doesn't match `trait` item signature --> $DIR/self-without-lifetime-constraint.rs:45:5 | LL | fn column_result(value: ValueRef<'_>) -> FromSqlResult; | -------------------------------------------------------------------- expected `fn(ValueRef<'1>) -> Result<(&'2 str, &'1 &'2 str), FromSqlError>` ... LL | fn column_result(value: ValueRef<'_>) -> FromSqlResult<&str, &&str> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(ValueRef<'1>) -> Result<(&'1 str, &'1 &'1 str), FromSqlError>` | = note: expected `fn(ValueRef<'1>) -> Result<(&'2 str, &'1 &'2 str), FromSqlError>` found `fn(ValueRef<'1>) -> Result<(&'1 str, &'1 &'1 str), FromSqlError>` help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait` --> $DIR/self-without-lifetime-constraint.rs:41:60 | LL | fn column_result(value: ValueRef<'_>) -> FromSqlResult; | ^^^^ consider borrowing this type parameter in the trait error: aborting due to previous error