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Merge #8560
8560: Escape characters in doc comments in macros correctly r=jonas-schievink a=ChayimFriedman2 Previously they were escaped twice, both by `.escape_default()` and the debug view of strings (`{:?}`). This leads to things like newlines or tabs in documentation comments being `\\n`, but we unescape literals only once, ending up with `\n`. This was hard to spot because CMark unescaped them (at least for `'` and `"`), but it did not do so in code blocks. This also was the root cause of #7781. This issue was solved by using `.escape_debug()` instead of `.escape_default()`, but the real issue remained. We can bring the `.escape_default()` back by now, however I didn't do it because it is probably slower than `.escape_debug()` (more work to do), and also in order to change the code the least. Example (the keyword and primitive docs are `include!()`d at https://doc.rust-lang.org/src/std/lib.rs.html#570-578, and thus originate from macro): Before: ![image](https://user-images.githubusercontent.com/24700207/115130096-40544300-9ff5-11eb-847b-969e7034e8a4.png) After: ![image](https://user-images.githubusercontent.com/24700207/115130143-9cb76280-9ff5-11eb-9281-323746089440.png) Co-authored-by: Chayim Refael Friedman <chayimfr@gmail.com>
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+23
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lines changed

crates/mbe/src/syntax_bridge.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -213,7 +213,7 @@ fn doc_comment_text(comment: &ast::Comment) -> SmolStr {
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// Quote the string
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// Note that `tt::Literal` expect an escaped string
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let text = format!("{:?}", text.escape_debug().to_string());
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let text = format!("\"{}\"", text.escape_debug());
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text.into()
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}
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crates/mbe/src/tests/expand.rs

Lines changed: 22 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -936,7 +936,7 @@ fn test_meta_doc_comments() {
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MultiLines Doc
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*/
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}"#,
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"# [doc = \" Single Line Doc 1\"] # [doc = \"\\\\n MultiLines Doc\\\\n \"] fn bar () {}",
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"# [doc = \" Single Line Doc 1\"] # [doc = \"\\n MultiLines Doc\\n \"] fn bar () {}",
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);
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}
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@@ -977,7 +977,27 @@ fn test_meta_doc_comments_non_latin() {
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莊生曉夢迷蝴蝶,望帝春心託杜鵑。
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*/
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}"#,
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"# [doc = \" 錦瑟無端五十弦,一弦一柱思華年。\"] # [doc = \"\\\\n 莊生曉夢迷蝴蝶,望帝春心託杜鵑。\\\\n \"] fn bar () {}",
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"# [doc = \" 錦瑟無端五十弦,一弦一柱思華年。\"] # [doc = \"\\n 莊生曉夢迷蝴蝶,望帝春心託杜鵑。\\n \"] fn bar () {}",
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);
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}
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#[test]
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fn test_meta_doc_comments_escaped_characters() {
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parse_macro(
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r#"
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macro_rules! foo {
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($(#[$ i:meta])+) => (
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$(#[$ i])+
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fn bar() {}
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)
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}
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"#,
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)
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.assert_expand_items(
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r#"foo! {
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/// \ " '
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}"#,
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r#"# [doc = " \\ \" \'"] fn bar () {}"#,
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);
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}
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