src/test/ui/traits/suggest-where-clause.stderr

   1 error[E0277]: the size for values of type `U` cannot be known at compilation time
   2   --> $DIR/suggest-where-clause.rs:7:20
   3    |
   4 LL | fn check<T: Iterator, U: ?Sized>() {
   5    |                       - this type parameter needs to be `std::marker::Sized`
   6 LL |     // suggest a where-clause, if needed
   7 LL |     mem::size_of::<U>();
   8    |                    ^ doesn't have a size known at compile-time
   9    |
  10 note: required by a bound in `std::mem::size_of`
  11   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
  12    |
  13 LL | pub const fn size_of<T>() -> usize {
  14    |                      ^ required by this bound in `std::mem::size_of`
  15 help: consider removing the `?Sized` bound to make the type parameter `Sized`
  16    |
  17 LL - fn check<T: Iterator, U: ?Sized>() {
  18 LL + fn check<T: Iterator, U>() {
  19    |
  20
  21 error[E0277]: the size for values of type `U` cannot be known at compilation time
  22   --> $DIR/suggest-where-clause.rs:10:20
  23    |
  24 LL | fn check<T: Iterator, U: ?Sized>() {
  25    |                       - this type parameter needs to be `std::marker::Sized`
  26 ...
  27 LL |     mem::size_of::<Misc<U>>();
  28    |                    ^^^^^^^ doesn't have a size known at compile-time
  29    |
  30 note: required because it appears within the type `Misc<U>`
  31   --> $DIR/suggest-where-clause.rs:3:8
  32    |
  33 LL | struct Misc<T:?Sized>(T);
  34    |        ^^^^
  35 note: required by a bound in `std::mem::size_of`
  36   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
  37    |
  38 LL | pub const fn size_of<T>() -> usize {
  39    |                      ^ required by this bound in `std::mem::size_of`
  40 help: consider removing the `?Sized` bound to make the type parameter `Sized`
  41    |
  42 LL - fn check<T: Iterator, U: ?Sized>() {
  43 LL + fn check<T: Iterator, U>() {
  44    |
  45
  46 error[E0277]: the trait bound `u64: From<T>` is not satisfied
  47   --> $DIR/suggest-where-clause.rs:15:5
  48    |
  49 LL |     <u64 as From<T>>::from;
  50    |     ^^^^^^^^^^^^^^^^^^^^^^ the trait `From<T>` is not implemented for `u64`
  51    |
  52 help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
  53    |
  54 LL | fn check<T: Iterator, U: ?Sized>() where u64: From<T> {
  55    |                                    ++++++++++++++++++
  56
  57 error[E0277]: the trait bound `u64: From<<T as Iterator>::Item>` is not satisfied
  58   --> $DIR/suggest-where-clause.rs:18:5
  59    |
  60 LL |     <u64 as From<<T as Iterator>::Item>>::from;
  61    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `From<<T as Iterator>::Item>` is not implemented for `u64`
  62    |
  63 help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
  64    |
  65 LL | fn check<T: Iterator, U: ?Sized>() where u64: From<<T as Iterator>::Item> {
  66    |                                    ++++++++++++++++++++++++++++++++++++++
  67
  68 error[E0277]: the trait bound `Misc<_>: From<T>` is not satisfied
  69   --> $DIR/suggest-where-clause.rs:23:5
  70    |
  71 LL |     <Misc<_> as From<T>>::from;
  72    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `From<T>` is not implemented for `Misc<_>`
  73
  74 error[E0277]: the size for values of type `[T]` cannot be known at compilation time
  75   --> $DIR/suggest-where-clause.rs:28:20
  76    |
  77 LL |     mem::size_of::<[T]>();
  78    |                    ^^^ doesn't have a size known at compile-time
  79    |
  80    = help: the trait `Sized` is not implemented for `[T]`
  81 note: required by a bound in `std::mem::size_of`
  82   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
  83    |
  84 LL | pub const fn size_of<T>() -> usize {
  85    |                      ^ required by this bound in `std::mem::size_of`
  86
  87 error[E0277]: the size for values of type `[&U]` cannot be known at compilation time
  88   --> $DIR/suggest-where-clause.rs:31:20
  89    |
  90 LL |     mem::size_of::<[&U]>();
  91    |                    ^^^^ doesn't have a size known at compile-time
  92    |
  93    = help: the trait `Sized` is not implemented for `[&U]`
  94 note: required by a bound in `std::mem::size_of`
  95   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
  96    |
  97 LL | pub const fn size_of<T>() -> usize {
  98    |                      ^ required by this bound in `std::mem::size_of`
  99
 100 error: aborting due to 7 previous errors
 101
 102 For more information about this error, try `rustc --explain E0277`.