Change:
In we account for the visible char width when calculating the label and span positions, but we do not do so for the vertical bar tying them together, causing the following output: where it should be (Found during )
I would like to solve this as a first time issue. Best with some pointers where to start :)
the code that draws the vertical lines is at and the one that draws the span labels is right below I think the error might be using instead of , but I'm not entirely certain. If this is your first time compiling , you probably want to read the , but the TL;DR: is "run to build the compiler up to the first stage and update the test output files". You might also want to wait until the linked PR is merged so you have a test case, unless you wish to come up with a new one (look for a test that has multiple labels in the same span and pad the source to the left with unicode chars on non-1 width).
Thank you! I did read the rustc guide, and even compiled it on my own once. But thanks for the direction, and the note to the PR. I'll do my best :wink:

Discussion:
return vec![]; } <del> // Write the colunmn separator. </del> <ins> // Write the column separator. </ins> // // After this we will have: //

//   |  __________ //   | |    | //   | | <del> // 3 | </del> <ins> // 3 | | </ins> // 4 | | } //   | |_ for &(pos, annotation) in &annotations_position {

if pos > 1 && (annotation.has_label() || annotation.takes_space()) { for p in line_offset + 1..=line_offset + pos { buffer.putc(p, <del> code_offset + annotation.start_col - margin.computed_left, </del> <ins> (code_offset + annotation.start_col).saturating_sub(left), </ins> '|', style); }

<ins> // 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` } </ins>

<ins> 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`. </ins>

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