error[E0277]: the size for values of type `U` cannot be known at compilation time --> $DIR/suggest-where-clause.rs:7:20 | LL | fn check() { | - this type parameter needs to be `std::marker::Sized` LL | // suggest a where-clause, if needed LL | mem::size_of::(); | ^ doesn't have a size known at compile-time | note: required by a bound in `std::mem::size_of` --> $SRC_DIR/core/src/mem/mod.rs:LL:COL help: consider removing the `?Sized` bound to make the type parameter `Sized` | LL - fn check() { LL + fn check() { | error[E0277]: the size for values of type `U` cannot be known at compilation time --> $DIR/suggest-where-clause.rs:10:20 | LL | fn check() { | - this type parameter needs to be `std::marker::Sized` ... LL | mem::size_of::>(); | ^^^^^^^ doesn't have a size known at compile-time | note: required because it appears within the type `Misc` --> $DIR/suggest-where-clause.rs:3:8 | LL | struct Misc(T); | ^^^^ note: required by a bound in `std::mem::size_of` --> $SRC_DIR/core/src/mem/mod.rs:LL:COL help: consider removing the `?Sized` bound to make the type parameter `Sized` | LL - fn check() { LL + fn check() { | error[E0277]: the trait bound `u64: From` is not satisfied --> $DIR/suggest-where-clause.rs:15:5 | LL | >::from; | ^^^^^^^^^^^^^^^^^^^^^^ the trait `From` is not implemented for `u64` | help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement | LL | fn check() where u64: From { | ++++++++++++++++++ error[E0277]: the trait bound `u64: From<::Item>` is not satisfied --> $DIR/suggest-where-clause.rs:18:5 | LL | ::Item>>::from; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `From<::Item>` is not implemented for `u64` | help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement | LL | fn check() where u64: From<::Item> { | ++++++++++++++++++++++++++++++++++++++ error[E0277]: the trait bound `Misc<_>: From` is not satisfied --> $DIR/suggest-where-clause.rs:23:5 | LL | as From>::from; | ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `From` is not implemented for `Misc<_>` error[E0277]: the size for values of type `[T]` cannot be known at compilation time --> $DIR/suggest-where-clause.rs:28:20 | LL | mem::size_of::<[T]>(); | ^^^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `[T]` note: required by a bound in `std::mem::size_of` --> $SRC_DIR/core/src/mem/mod.rs:LL:COL error[E0277]: the size for values of type `[&U]` cannot be known at compilation time --> $DIR/suggest-where-clause.rs:31:20 | LL | mem::size_of::<[&U]>(); | ^^^^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `[&U]` note: required by a bound in `std::mem::size_of` --> $SRC_DIR/core/src/mem/mod.rs:LL:COL error: aborting due to 7 previous errors For more information about this error, try `rustc --explain E0277`.