Draw vertical lines in compiler error messages with multiline annotations correctly when non-1space unicode characters are to the left

For this we use the correct calculation of the 'left' identation

Author: TheSamsa

src/librustc_errors/emitter.rs

@@ -835,7 +835,7 @@ impl EmitterWriter {
  return vec![];
  }
 
- // Write the colunmn separator.
+ // Write the column separator.
  //
  // After this we will have:
  //
@@ -906,7 +906,7 @@ impl EmitterWriter {
  // | __________
  // | | |
  // | |
- // 3 |
+ // 3 | |
  // 4 | | }
  // | |_
  for &(pos, annotation) in &annotations_position {
@@ -920,7 +920,7 @@ impl EmitterWriter {
  if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
  for p in line_offset + 1..=line_offset + pos {
  buffer.putc(p,
- code_offset + annotation.start_col - margin.computed_left,
+ (code_offset + annotation.start_col).saturating_sub(left),
  '|',
  style);
  }

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

@@ -0,0 +1,7 @@
+// ignore-tidy-linelength
+
+fn main() {
+ let unicode_is_fun = "؁‱ஹ௸௵꧄.ဪ꧅⸻𒈙𒐫﷽𒌄𒈟𒍼𒁎𒀱𒌧𒅃 𒈓𒍙𒊎𒄡𒅌𒁏𒀰𒐪𒐩𒈙𒐫𪚥";
+ let _ = "ༀ༁༂༃༄༅༆༇༈༉༊་༌།༎༏༐༑༒༓༔༕༖༗༘༙༚༛༜༝༞༟༠༡༢༣༤༥༦༧༨༩༪༫༬༭༮༯༰༱༲༳༴༵༶༷༸༹༺༻༼༽༾༿ཀཁགགྷངཅཆཇ཈ཉཊཋཌཌྷཎཏཐདདྷནཔཕབབྷམཙཚཛཛྷཝཞཟའཡརལཤཥསཧཨཀྵཪཫཬ཭཮཯཰ཱཱཱིིུུྲྀཷླྀཹེཻོཽཾཿ྄ཱྀྀྂྃ྅྆྇ྈྉྊྋྌྍྎྏྐྑྒྒྷྔྕྖྗ྘ྙྚྛྜྜྷྞྟྠྡྡྷྣྤྥྦྦྷྨྩྪྫྫྷྭྮྯྰྱྲླྴྵྶྷྸྐྵྺྻྼ྽྾྿࿀࿁࿂࿃࿄࿅࿆࿇࿈࿉࿊࿋࿌࿍࿎࿏࿐࿑࿒࿓࿔࿕࿖࿗࿘࿙࿚"; let _a = unicode_is_fun + " really fun!";
+ //~^ ERROR binary operation `+` cannot be applied to type `&str`
+}

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

@@ -0,0 +1,17 @@
+error[E0369]: binary operation `+` cannot be applied to type `&str`
+ --> $DIR/non-1-width-unicode-multiline-label.rs:5:260
+ |
+LL | ...ཽཾཿ྄ཱྀྀྂྃ྅྆྇ྈྉྊྋྌྍྎྏྐྑྒྒྷྔྕྖྗ྘ྙྚྛྜྜྷྞྟྠྡྡྷྣྤྥྦྦྷྨྩྪྫྫྷྭྮྯྰྱྲླྴྵྶྷྸྐྵྺྻྼ྽྾྿࿀࿁࿂࿃࿄࿅࿆࿇...࿋࿌࿍࿎࿏࿐࿑࿒࿓࿔࿕࿖࿗࿘࿙࿚"; let _a = unicode_is_fun + " really fun!";
+ | -------------- ^ -------------- &str
+ | | |
+ | | `+` cannot be used to concatenate two `&str` strings
+ | &str
+ |
+help: `to_owned()` can be used to create an owned `String` from a string reference. 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
+ |
+LL | let _ = "ༀ༁༂༃༄༅༆༇༈༉༊་༌།༎༏༐༑༒༓༔༕༖༗༘༙༚༛༜༝༞༟༠༡༢༣༤༥༦༧༨༩༪༫༬༭༮༯༰༱༲༳༴༵༶༷༸༹༺༻༼༽༾༿ཀཁགགྷངཅཆཇ཈ཉཊཋཌཌྷཎཏཐདདྷནཔཕབབྷམཙཚཛཛྷཝཞཟའཡརལཤཥསཧཨཀྵཪཫཬ཭཮཯཰ཱཱཱིིུུྲྀཷླྀཹེཻོཽཾཿ྄ཱྀྀྂྃ྅྆྇ྈྉྊྋྌྍྎྏྐྑྒྒྷྔྕྖྗ྘ྙྚྛྜྜྷྞྟྠྡྡྷྣྤྥྦྦྷྨྩྪྫྫྷྭྮྯྰྱྲླྴྵྶྷྸྐྵྺྻྼ྽྾྿࿀࿁࿂࿃࿄࿅࿆࿇࿈࿉࿊࿋࿌࿍࿎࿏࿐࿑࿒࿓࿔࿕࿖࿗࿘࿙࿚"; let _a = unicode_is_fun.to_owned() + " really fun!";
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0369`.

src/test/ui/terminal-width/non-whitespace-trimming-unicode.stderr

@@ -3,7 +3,7 @@ error[E0308]: mismatched types
  |
 LL | ...♭♮♯♰♱♲♳♴♵♶♷♸♹♺♻♼♽♾♿⚀⚁⚂⚃⚄⚅⚆⚈⚉4"; let _: () = 42; let _: &str = "🦀☀☁☂☃☄★☆☇☈☉☊☋☌☍☎☏☐☑☒☓ ☖☗☘☙☚☛☜☝☞☟☠☡☢☣☤☥☦☧☨☩☪☫☬☭☮☯☰☱☲☳☴☵☶☷☸☹☺☻☼☽☾☿♀♁♂♃♄...
  | -- ^^ expected `()`, found integer
- |  |
+ | |
  | expected due to this
 
 error: aborting due to previous error