4 files changed, 50 insertions, 22 deletions

diff --git a/crates/ra_ide/src/syntax_highlighting/html.rs b/crates/ra_ide/src/syntax_highlighting/html.rs
index 99b6b25ab..0c74f7370 100644
--- a/crates/ra_ide/src/syntax_highlighting/html.rs
+++ b/crates/ra_ide/src/syntax_highlighting/html.rs
@@ -64,6 +64,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 .lifetime           { color: #DFAF8F; font-style: italic; }
 .comment            { color: #7F9F7F; }
+.documentation      { color: #629755; }
+.injected           { opacity: 0.65 ; }
 .struct, .enum      { color: #7CB8BB; }
 .enum_variant       { color: #BDE0F3; }
 .string_literal     { color: #CC9393; }
diff --git a/crates/ra_ide/src/syntax_highlighting/injection.rs b/crates/ra_ide/src/syntax_highlighting/injection.rs
index 929a5cc5c..181c21256 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, Highlight, 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();
@@ -152,18 +155,24 @@ pub(super) fn highlight_doc_comment(
         let mut start_offset = None;
         let mut end_offset = None;
         for (line_start, orig_line_start) in range_mapping.range(..h.range.end()).rev() {
+            // It's possible for orig_line_start - line_start to be negative. Add h.range.start()
+            // here and remove it from the end range after the loop below so that the values are
+            // always non-negative.
+            let offset = h.range.start() + orig_line_start - line_start;
             if line_start <= &h.range.start() {
-                start_offset.get_or_insert(orig_line_start - line_start);
+                start_offset.get_or_insert(offset);
                 break;
             } else {
-                end_offset.get_or_insert(orig_line_start - line_start);
+                end_offset.get_or_insert(offset);
             }
         }
         if let Some(start_offset) = start_offset {
             h.range = TextRange::new(
-                h.range.start() + start_offset,
-                h.range.end() + end_offset.unwrap_or(start_offset),
+                start_offset,
+                h.range.end() + end_offset.unwrap_or(start_offset) - h.range.start(),
             );
+
+            h.highlight |= HighlightModifier::Injected;
             stack.add(h);
         }
     }
@@ -173,6 +182,7 @@ pub(super) fn highlight_doc_comment(
     for comment in new_comments {
         stack.add(comment);
     }
-    stack.pop_and_inject(false);
-    stack.pop_and_inject(true);
+    stack.pop_and_inject(None);
+    stack
+        .pop_and_inject(Some(Highlight::from(HighlightTag::Generic) | HighlightModifier::Injected));
 }
diff --git a/crates/ra_ide/src/syntax_highlighting/tags.rs b/crates/ra_ide/src/syntax_highlighting/tags.rs
index 400d22fb6..e8e251cfc 100644
--- a/crates/ra_ide/src/syntax_highlighting/tags.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tags.rs
@@ -27,6 +27,7 @@ pub enum HighlightTag {
     Field,
     FormatSpecifier,
     Function,
+    Generic,
     Keyword,
     Lifetime,
     Macro,
@@ -56,6 +57,8 @@ pub enum HighlightModifier {
     /// `foo` in `fn foo(x: i32)` is a definition, `foo` in `foo(90 + 2)` is
     /// not.
     Definition,
+    Documentation,
+    Injected,
     Mutable,
     Unsafe,
 }
@@ -76,6 +79,7 @@ impl HighlightTag {
             HighlightTag::Field => "field",
             HighlightTag::FormatSpecifier => "format_specifier",
             HighlightTag::Function => "function",
+            HighlightTag::Generic => "generic",
             HighlightTag::Keyword => "keyword",
             HighlightTag::Lifetime => "lifetime",
             HighlightTag::Macro => "macro",
@@ -108,6 +112,8 @@ impl HighlightModifier {
         HighlightModifier::Attribute,
         HighlightModifier::ControlFlow,
         HighlightModifier::Definition,
+        HighlightModifier::Documentation,
+        HighlightModifier::Injected,
         HighlightModifier::Mutable,
         HighlightModifier::Unsafe,
     ];
@@ -117,6 +123,8 @@ impl HighlightModifier {
             HighlightModifier::Attribute => "attribute",
             HighlightModifier::ControlFlow => "control",
             HighlightModifier::Definition => "declaration",
+            HighlightModifier::Documentation => "documentation",
+            HighlightModifier::Injected => "injected",
             HighlightModifier::Mutable => "mutable",
             HighlightModifier::Unsafe => "unsafe",
         }
diff --git a/crates/ra_ide/src/syntax_highlighting/tests.rs b/crates/ra_ide/src/syntax_highlighting/tests.rs
index b4d56a7a0..b7fad9719 100644
--- a/crates/ra_ide/src/syntax_highlighting/tests.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tests.rs
@@ -2,10 +2,7 @@ use std::fs;
 
 use test_utils::{assert_eq_text, project_dir, read_text};
 
-use crate::{
-    mock_analysis::{single_file, MockAnalysis},
-    FileRange, TextRange,
-};
+use crate::{mock_analysis::single_file, FileRange, TextRange};
 
 #[test]
 fn test_highlighting() {
@@ -127,12 +124,10 @@ fn accidentally_quadratic() {
     let file = project_dir().join("crates/ra_syntax/test_data/accidentally_quadratic");
     let src = fs::read_to_string(file).unwrap();
 
-    let mut mock = MockAnalysis::new();
-    let file_id = mock.add_file("/main.rs", &src);
-    let host = mock.analysis_host();
+    let (analysis, file_id) = single_file(&src);
 
     // let t = std::time::Instant::now();
-    let _ = host.analysis().highlight(file_id).unwrap();
+    let _ = analysis.highlight(file_id).unwrap();
     // eprintln!("elapsed: {:?}", t.elapsed());
 }
 
@@ -140,16 +135,17 @@ fn accidentally_quadratic() {
 fn test_ranges() {
     let (analysis, file_id) = single_file(
         r#"
-            #[derive(Clone, Debug)]
-            struct Foo {
-                pub x: i32,
-                pub y: i32,
-            }"#,
+#[derive(Clone, Debug)]
+struct Foo {
+    pub x: i32,
+    pub y: i32,
+}
+"#,
     );
 
     // The "x"
     let highlights = &analysis
-        .highlight_range(FileRange { file_id, range: TextRange::at(82.into(), 1.into()) })
+        .highlight_range(FileRange { file_id, range: TextRange::at(45.into(), 1.into()) })
         .unwrap();
 
     assert_eq!(&highlights[0].highlight.to_string(), "field.declaration");
@@ -291,6 +287,9 @@ fn main() {
 fn test_highlight_doctest() {
     check_highlighting(
         r#"
+/// ```
+/// let _ = "early doctests should not go boom";
+/// ```
 struct Foo {
     bar: bool,
 }
@@ -344,6 +343,15 @@ impl Foo {
         true
     }
 }
+
+/// ```
+/// noop!(1);
+/// ```
+macro_rules! noop {
+    ($expr:expr) => {
+        $expr
+    }
+}
 "#
         .trim(),
         "crates/ra_ide/src/snapshots/highlight_doctest.html",