Esteban Küber 2d7795dfb9 Be more accurate about calculating display_col from a BytePos
No longer track "zero-width" chars in `SourceMap`, read directly from the line when calculating the `display_col` of a `BytePos`. Move `char_width` to `rustc_span` and use it from the emitter.

This change allows the following to properly align in terminals (depending on the font, the replaced control codepoints are rendered as 1 or 2 width, on my terminal they are rendered as 1, on VSCode text they are rendered as 2):

```
error: this file contains an unclosed delimiter
  --> $DIR/issue-68629.rs:5:17
   |
LL | ␜␟ts␀![{i
   |       -- unclosed delimiter
   |       |
   |       unclosed delimiter
LL | ␀␀  fn rݻoa>rݻm
   |                ^
```
2024-07-18 20:08:38 +00:00
..
2024-07-12 11:52:04 -04:00
2024-07-18 00:00:04 +00:00
2024-07-14 13:50:09 +09:00
2024-07-12 03:22:32 +00:00

UI Tests

This folder contains rustc's UI tests.

Test Directives (Headers)

Typically, a UI test will have some test directives / headers which are special comments that tell compiletest how to build and intepret a test.

As part of an on-going effort to rewrite compiletest (see https://github.com/rust-lang/compiler-team/issues/536), a major change proposal to change legacy compiletest-style headers // <directive> to ui_test-style headers //@ <directive> was accepted (see https://github.com/rust-lang/compiler-team/issues/512.

An example directive is ignore-test. In legacy compiletest style, the header would be written as

// ignore-test

but in ui_test style, the header would be written as

//@ ignore-test

compiletest is changed to accept only //@ directives for UI tests (currently), and will reject and report an error if it encounters any comments // <content> that may be parsed as an legacy compiletest-style test header. To fix this, you should migrate to the ui_test-style header //@ <content>.