Add line breaks to make message easier to read

compiler/rustc_typeck/src/check/op.rs

@@ -549,9 +549,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         is_assign: IsAssign,
         op: hir::BinOp,
     ) -> bool {
-        let str_concat_note = "String concatenation appends the string on the right to the \
+        let str_concat_note = "String concatenation appends the string on the right to the
-                                    string on the left and may require reallocation. This \
+string on the left and may require reallocation.
-                                    requires ownership of the string on the left.";
+This requires ownership of the string on the left.";
         let rm_borrow_msg = "remove the borrow to obtain an owned `String`";
         let to_owned_msg = "use `to_owned()` to create an owned `String` from a string reference";
 

src/test/ui/issues/issue-47377.stderr

@@ -7,7 +7,9 @@ LL |      let _a = b + ", World!";
    |               | `+` cannot be used to concatenate two `&str` strings
    |               &str
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |      let _a = b.to_owned() + ", World!";

src/test/ui/issues/issue-47380.stderr

@@ -7,7 +7,9 @@ LL |     println!("🦀🦀🦀🦀🦀"); let _a = b + ", World!";
    |                                      | `+` cannot be used to concatenate two `&str` strings
    |                                      &str
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     println!("🦀🦀🦀🦀🦀"); let _a = b.to_owned() + ", World!";

src/test/ui/span/issue-39018.stderr

@@ -7,7 +7,9 @@ LL |     let x = "Hello " + "World!";
    |             |        `+` cannot be used to concatenate two `&str` strings
    |             &str
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let x = "Hello ".to_owned() + "World!";
@@ -62,7 +64,9 @@ LL |     let _ = &a + &b;
    |             &String
    |             help: remove the borrow to obtain an owned `String`
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 
 error[E0369]: cannot add `String` to `&String`
   --> $DIR/issue-39018.rs:27:16
@@ -111,7 +115,9 @@ LL |     let _ = e + &b;
    |             | `+` cannot be used to concatenate two `&str` strings
    |             &String
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let _ = e.to_owned() + &b;
@@ -126,7 +132,9 @@ LL |     let _ = e + d;
    |             | `+` cannot be used to concatenate two `&str` strings
    |             &String
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let _ = e.to_owned() + d;
@@ -141,7 +149,9 @@ LL |     let _ = e + &d;
    |             | `+` cannot be used to concatenate two `&str` strings
    |             &String
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let _ = e.to_owned() + &d;
@@ -172,7 +182,9 @@ LL |     let _ = c + &d;
    |             | `+` cannot be used to concatenate two `&str` strings
    |             &str
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let _ = c.to_owned() + &d;
@@ -187,7 +199,9 @@ LL |     let _ = c + d;
    |             | `+` cannot be used to concatenate two `&str` strings
    |             &str
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let _ = c.to_owned() + d;

src/test/ui/str/str-concat-on-double-ref.stderr

@@ -7,7 +7,9 @@ LL |     let c = a + b;
    |             | `+` cannot be used to concatenate two `&str` strings
    |             &String
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let c = a.to_owned() + b;

src/test/ui/terminal-width/non-1-width-unicode-multiline-label.stderr

@@ -7,7 +7,9 @@ LL | ...ཽཾཿ྄ཱྀྀྂྃ྅྆྇ྈྉྊྋྌྍྎྏྐྑྒྒྷྔ
    |                                                  |              `+` cannot be used to concatenate two `&str` strings
    |                                                  &str
    |
-   = note: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left.
+   = note: String concatenation appends the string on the right to the
+           string on the left and may require reallocation.
+           This requires ownership of the string on the left.
 help: use `to_owned()` to create an owned `String` from a string reference
    |
 LL |     let _ = "ༀ༁༂༃༄༅༆༇༈༉༊་༌།༎༏༐༑༒༓༔༕༖༗༘༙༚༛༜༝༞༟༠༡༢༣༤༥༦༧༨༩༪༫༬༭༮༯༰༱༲༳༴༵༶༷༸༹༺༻༼༽༾༿ཀཁགགྷངཅཆཇ཈ཉཊཋཌཌྷཎཏཐདདྷནཔཕབབྷམཙཚཛཛྷཝཞཟའཡརལཤཥསཧཨཀྵཪཫཬ཭཮཯཰ཱཱཱིིུུྲྀཷླྀཹེཻོཽཾཿ྄ཱྀྀྂྃ྅྆྇ྈྉྊྋྌྍྎྏྐྑྒྒྷྔྕྖྗ྘ྙྚྛྜྜྷྞྟྠྡྡྷྣྤྥྦྦྷྨྩྪྫྫྷྭྮྯྰྱྲླྴྵྶྷྸྐྵྺྻྼ྽྾྿࿀࿁࿂࿃࿄࿅࿆࿇࿈࿉࿊࿋࿌࿍࿎࿏࿐࿑࿒࿓࿔࿕࿖࿗࿘࿙࿚"; let _a = unicode_is_fun.to_owned() + " really fun!";