From 117a28a06564946b2934b7960ec84477745a0ebe Mon Sep 17 00:00:00 2001
From: Luiz Carvalho <luizcmpc@gmail.com>
Date: Tue, 19 Dec 2023 00:32:55 -0300
Subject: [PATCH 1/2] fix(mbe): desugar doc correctly for mbe

Fixes #16110.

The way rust desugars doc comments when expanding macros
is rendering it as raw strings delimited with hashes.
Rust-analyzer wasn't aware of this, so the desugared doc
comments wouldn't match correctly when on the LHS of macro
declarations.

This PR fixes this by porting the code used by rustc: https://github.com/rust-lang/rust/blob/4cfdbd328b7171b2328d11b950b1af0978d6b1ef/compiler/rustc_ast/src/tokenstream.rs#L6837
---
 crates/hir-def/src/macro_expansion_tests/mbe.rs | 14 +++++++++-----
 crates/mbe/src/syntax_bridge.rs                 | 15 +++++++++++++--
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/crates/hir-def/src/macro_expansion_tests/mbe.rs b/crates/hir-def/src/macro_expansion_tests/mbe.rs
index 9bf2a50d57c..57dc50fb70d 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe.rs
@@ -1218,8 +1218,10 @@ m! {
 macro_rules! m {
     ($(#[$m:meta])+) => ( $(#[$m])+ fn bar() {} )
 }
-#[doc = " Single Line Doc 1"]
-#[doc = "\n        MultiLines Doc\n    "] fn bar() {}
+#[doc = r" Single Line Doc 1"]
+#[doc = "
+        MultiLines Doc
+    "] fn bar() {}
 "##]],
     );
 }
@@ -1260,8 +1262,10 @@ m! {
 macro_rules! m {
     ($(#[$ m:meta])+) => ( $(#[$m])+ fn bar() {} )
 }
-#[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() {}
+#[doc = r" 錦瑟無端五十弦，一弦一柱思華年。"]
+#[doc = r"
+        莊生曉夢迷蝴蝶，望帝春心託杜鵑。
+    "] fn bar() {}
 "##]],
     );
 }
@@ -1281,7 +1285,7 @@ m! {
 macro_rules! m {
     ($(#[$m:meta])+) => ( $(#[$m])+ fn bar() {} )
 }
-#[doc = " \\ \" \'"] fn bar() {}
+#[doc = r#" \ " '"#] fn bar() {}
 "##]],
     );
 }
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 3440c1dd8ca..77bda1f9af3 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -406,9 +406,20 @@ fn doc_comment_text(comment: &ast::Comment) -> SmolStr {
         text = &text[0..text.len() - 2];
     }
 
-    // Quote the string
+    let mut num_of_hashes = 0;
+    let mut count = 0;
+    for ch in text.chars() {
+        count = match ch {
+            '"' => 1,
+            '#' if count > 0 => count + 1,
+            _ => 0,
+        };
+        num_of_hashes = num_of_hashes.max(count);
+    }
+
+    // Quote raw string with delimiters
     // Note that `tt::Literal` expect an escaped string
-    let text = format!("\"{}\"", text.escape_debug());
+    let text = format!("r{delim}\"{text}\"{delim}", delim = "#".repeat(num_of_hashes));
     text.into()
 }
 

From 6f58e98f2ca1bbb19e6dfee9f2373d2e4d7715ed Mon Sep 17 00:00:00 2001
From: Luiz Carvalho <luizcmpc@gmail.com>
Date: Tue, 19 Dec 2023 01:03:00 -0300
Subject: [PATCH 2/2] fix(mbe): update test

---
 crates/hir-def/src/macro_expansion_tests/mbe.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/hir-def/src/macro_expansion_tests/mbe.rs b/crates/hir-def/src/macro_expansion_tests/mbe.rs
index 57dc50fb70d..f2046bfbce4 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe.rs
@@ -1219,7 +1219,7 @@ macro_rules! m {
     ($(#[$m:meta])+) => ( $(#[$m])+ fn bar() {} )
 }
 #[doc = r" Single Line Doc 1"]
-#[doc = "
+#[doc = r"
         MultiLines Doc
     "] fn bar() {}
 "##]],