Review comments: split requirement text to multiple lines for readabi…

…lity

src/librustc_typeck/check/method/suggest.rs

@@ -639,7 +639,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                     None => format!("`{}`", p),
                                     Some((parent_p, _)) => {
                                         collect_type_param_suggestions(self_ty, parent_pred, &p);
-                                        format!("`{}` which is required by `{}`", p, parent_p)
+                                        format!("`{}`\nwhich is required by `{}`", p, parent_p)
                                     }
                                 },
                             })

src/test/ui/derives/derive-assoc-type-not-impl.stderr

@@ -14,7 +14,8 @@ LL |     Bar::<NotClone> { x: 1 }.clone();
    |                              ^^^^^ method not found in `Bar<NotClone>`
    |
    = note: the method `clone` exists but the following trait bounds were not satisfied:
-           `NotClone: std::clone::Clone` which is required by `Bar<NotClone>: std::clone::Clone`
+           `NotClone: std::clone::Clone`
+           which is required by `Bar<NotClone>: std::clone::Clone`
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `std::clone::Clone`

src/test/ui/issues/issue-21596.stderr

@@ -7,7 +7,8 @@ LL |     println!("{}", z.to_string());
    = note: try using `<*const T>::as_ref()` to get a reference to the type behind the pointer: https://doc.rust-lang.org/std/primitive.pointer.html#method.as_ref
    = note: using `<*const T>::as_ref()` on a pointer which is unaligned or points to invalid or uninitialized memory is undefined behavior
    = note: the method `to_string` exists but the following trait bounds were not satisfied:
-           `*const u8: std::fmt::Display` which is required by `*const u8: std::string::ToString`
+           `*const u8: std::fmt::Display`
+           which is required by `*const u8: std::string::ToString`
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-31173.stderr

@@ -22,8 +22,10 @@ LL | pub struct TakeWhile<I, P> {
    | -------------------------- doesn't satisfy `<_ as std::iter::Iterator>::Item = &_`
    |
    = note: the method `collect` exists but the following trait bounds were not satisfied:
-           `<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]> as std::iter::Iterator>::Item = &_` which is required by `std::iter::Cloned<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]>>: std::iter::Iterator`
-           `std::iter::Cloned<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]>>: std::iter::Iterator` which is required by `&mut std::iter::Cloned<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]>>: std::iter::Iterator`
+           `<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]> as std::iter::Iterator>::Item = &_`
+           which is required by `std::iter::Cloned<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]>>: std::iter::Iterator`
+           `std::iter::Cloned<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]>>: std::iter::Iterator`
+           which is required by `&mut std::iter::Cloned<std::iter::TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:10:39: 13:6 found_e:_]>>: std::iter::Iterator`
 
 error: aborting due to 2 previous errors
 

src/test/ui/methods/method-call-err-msg.stderr

@@ -44,7 +44,8 @@ LL |      .take()
    |       ^^^^ method not found in `Foo`
    |
    = note: the method `take` exists but the following trait bounds were not satisfied:
-           `Foo: std::iter::Iterator` which is required by `&mut Foo: std::iter::Iterator`
+           `Foo: std::iter::Iterator`
+           which is required by `&mut Foo: std::iter::Iterator`
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following traits define an item `take`, perhaps you need to implement one of them:
            candidate #1: `std::io::Read`

src/test/ui/mismatched_types/issue-36053-2.stderr

@@ -13,9 +13,12 @@ LL | pub struct Filter<I, P> {
    | ----------------------- doesn't satisfy `_: std::iter::Iterator`
    |
    = note: the method `count` exists but the following trait bounds were not satisfied:
-           `<[closure@$DIR/issue-36053-2.rs:11:39: 11:53] as std::ops::FnOnce<(&&str,)>>::Output = bool` which is required by `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
-           `[closure@$DIR/issue-36053-2.rs:11:39: 11:53]: std::ops::FnMut<(&&str,)>` which is required by `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
-           `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator` which is required by `&mut std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
+           `<[closure@$DIR/issue-36053-2.rs:11:39: 11:53] as std::ops::FnOnce<(&&str,)>>::Output = bool`
+           which is required by `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
+           `[closure@$DIR/issue-36053-2.rs:11:39: 11:53]: std::ops::FnMut<(&&str,)>`
+           which is required by `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
+           `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
+           which is required by `&mut std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:11:39: 11:53]>: std::iter::Iterator`
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/issue-36053-2.rs:11:32

src/test/ui/suggestions/missing-trait-bounds-for-method-call.stderr

@@ -11,8 +11,10 @@ LL |         self.foo();
    |              ^^^ method not found in `&Foo<T>`
    |
    = note: the method `foo` exists but the following trait bounds were not satisfied:
-           `T: Bar` which is required by `Foo<T>: Bar`
-           `T: std::default::Default` which is required by `Foo<T>: Bar`
+           `T: Bar`
+           which is required by `Foo<T>: Bar`
+           `T: std::default::Default`
+           which is required by `Foo<T>: Bar`
    = help: items from traits can only be used if the trait is implemented and in scope
 help: consider restricting the type parameters to satisfy the obligations
    |
@@ -32,7 +34,8 @@ LL |         self.foo();
    |              ^^^ method not found in `&Fin<T>`
    |
    = note: the method `foo` exists but the following trait bounds were not satisfied:
-           `T: std::default::Default` which is required by `Fin<T>: Bar`
+           `T: std::default::Default`
+           which is required by `Fin<T>: Bar`
    = help: items from traits can only be used if the trait is implemented and in scope
 help: consider restricting the type parameter to satisfy the obligation
    |

src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr

@@ -37,7 +37,8 @@ LL | pub struct BufWriter<W: Write> {
    | ------------------------------ doesn't satisfy `_: std::io::Write`
    |
    = note: the method `write_fmt` exists but the following trait bounds were not satisfied:
-           `&dyn std::io::Write: std::io::Write` which is required by `std::io::BufWriter<&dyn std::io::Write>: std::io::Write`
+           `&dyn std::io::Write: std::io::Write`
+           which is required by `std::io::BufWriter<&dyn std::io::Write>: std::io::Write`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 4 previous errors

src/test/ui/union/union-derive-clone.stderr

@@ -23,7 +23,8 @@ LL |     let w = u.clone();
    |               ^^^^^ method not found in `U5<CloneNoCopy>`
    |
    = note: the method `clone` exists but the following trait bounds were not satisfied:
-           `CloneNoCopy: std::marker::Copy` which is required by `U5<CloneNoCopy>: std::clone::Clone`
+           `CloneNoCopy: std::marker::Copy`
+           which is required by `U5<CloneNoCopy>: std::clone::Clone`
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `std::clone::Clone`

src/test/ui/unique-object-noncopyable.stderr

@@ -16,8 +16,10 @@ LL | pub struct Box<T: ?Sized>(Unique<T>);
    | ------------------------------------- doesn't satisfy `std::boxed::Box<dyn Foo>: std::clone::Clone`
    |
    = note: the method `clone` exists but the following trait bounds were not satisfied:
-           `dyn Foo: std::clone::Clone` which is required by `std::boxed::Box<dyn Foo>: std::clone::Clone`
-           `dyn Foo: std::marker::Sized` which is required by `std::boxed::Box<dyn Foo>: std::clone::Clone`
+           `dyn Foo: std::clone::Clone`
+           which is required by `std::boxed::Box<dyn Foo>: std::clone::Clone`
+           `dyn Foo: std::marker::Sized`
+           which is required by `std::boxed::Box<dyn Foo>: std::clone::Clone`
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `std::clone::Clone`

src/test/ui/unique-pinned-nocopy.stderr

@@ -13,7 +13,8 @@ LL | pub struct Box<T: ?Sized>(Unique<T>);
    | ------------------------------------- doesn't satisfy `std::boxed::Box<R>: std::clone::Clone`
    |
    = note: the method `clone` exists but the following trait bounds were not satisfied:
-           `R: std::clone::Clone` which is required by `std::boxed::Box<R>: std::clone::Clone`
+           `R: std::clone::Clone`
+           which is required by `std::boxed::Box<R>: std::clone::Clone`
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `std::clone::Clone`