Merge #4903

4903: Add highlighting support for doc comments r=matklad a=Nashenas88

The language server protocol includes a semantic modifier for documentation. This change exports that modifier for doc comments so users can choose to highlight them differently compared to regular comments.

Example:
<img width="375" alt="Screen Shot 2020-06-16 at 10 34 14 AM" src="https://user-images.githubusercontent.com/1673130/84788271-f6599580-afbc-11ea-96e5-7a0215da620b.png">

CC @woody77 

Co-authored-by: Paul Daniel Faria <[email protected]>

2 files changed, 9 insertions, 2 deletions

diff --git a/crates/ra_ide/src/syntax_highlighting/injection.rs b/crates/ra_ide/src/syntax_highlighting/injection.rs
index 929a5cc5c..415f24a6d 100644
--- a/crates/ra_ide/src/syntax_highlighting/injection.rs
+++ b/crates/ra_ide/src/syntax_highlighting/injection.rs
@@ -7,7 +7,10 @@ use hir::Semantics;
 use ra_syntax::{ast, AstToken, SyntaxNode, SyntaxToken, TextRange, TextSize};
 use stdx::SepBy;
 
-use crate::{call_info::ActiveParameter, Analysis, HighlightTag, HighlightedRange, RootDatabase};
+use crate::{
+    call_info::ActiveParameter, Analysis, HighlightModifier, HighlightTag, HighlightedRange,
+    RootDatabase,
+};
 
 use super::HighlightedRangeStack;
 
@@ -118,7 +121,7 @@ pub(super) fn extract_doc_comments(
                     range.start(),
                     range.start() + TextSize::try_from(pos).unwrap(),
                 ),
-                highlight: HighlightTag::Comment.into(),
+                highlight: HighlightTag::Comment | HighlightModifier::Documentation,
                 binding_hash: None,
             });
             line_start += range.len() - TextSize::try_from(pos).unwrap();
@@ -164,6 +167,7 @@ pub(super) fn highlight_doc_comment(
                 h.range.start() + start_offset,
                 h.range.end() + end_offset.unwrap_or(start_offset),
             );
+
             stack.add(h);
         }
     }
diff --git a/crates/ra_ide/src/syntax_highlighting/tags.rs b/crates/ra_ide/src/syntax_highlighting/tags.rs
index 400d22fb6..93bbb4b4d 100644
--- a/crates/ra_ide/src/syntax_highlighting/tags.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tags.rs
@@ -56,6 +56,7 @@ pub enum HighlightModifier {
     /// `foo` in `fn foo(x: i32)` is a definition, `foo` in `foo(90 + 2)` is
     /// not.
     Definition,
+    Documentation,
     Mutable,
     Unsafe,
 }
@@ -108,6 +109,7 @@ impl HighlightModifier {
         HighlightModifier::Attribute,
         HighlightModifier::ControlFlow,
         HighlightModifier::Definition,
+        HighlightModifier::Documentation,
         HighlightModifier::Mutable,
         HighlightModifier::Unsafe,
     ];
@@ -117,6 +119,7 @@ impl HighlightModifier {
             HighlightModifier::Attribute => "attribute",
             HighlightModifier::ControlFlow => "control",
             HighlightModifier::Definition => "declaration",
+            HighlightModifier::Documentation => "documentation",
             HighlightModifier::Mutable => "mutable",
             HighlightModifier::Unsafe => "unsafe",
         }