4 files changed, 47 insertions, 7 deletions

diff --git a/crates/ra_ide/src/syntax_highlighting/html.rs b/crates/ra_ide/src/syntax_highlighting/html.rs
index 5bada6252..99b6b25ab 100644
--- a/crates/ra_ide/src/syntax_highlighting/html.rs
+++ b/crates/ra_ide/src/syntax_highlighting/html.rs
@@ -19,7 +19,7 @@ pub(crate) fn highlight_as_html(db: &RootDatabase, file_id: FileId, rainbow: boo
         )
     }
 
-    let ranges = highlight(db, file_id, None);
+    let ranges = highlight(db, file_id, None, false);
     let text = parse.tree().syntax().to_string();
     let mut prev_pos = TextSize::from(0);
     let mut buf = String::new();
@@ -84,6 +84,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .variable           { color: #DCDCCC; }
 .format_specifier   { color: #CC696B; }
 .mutable            { text-decoration: underline; }
+.unresolved_reference { color: #FC5555; }
+.escape_sequence    { color: #94BFF3; }
 
 .keyword            { color: #F0DFAF; font-weight: bold; }
 .keyword.unsafe     { color: #BC8383; font-weight: bold; }
diff --git a/crates/ra_ide/src/syntax_highlighting/injection.rs b/crates/ra_ide/src/syntax_highlighting/injection.rs
index 3575a0fc6..929a5cc5c 100644
--- a/crates/ra_ide/src/syntax_highlighting/injection.rs
+++ b/crates/ra_ide/src/syntax_highlighting/injection.rs
@@ -53,6 +53,10 @@ pub(super) fn highlight_injection(
 /// Mapping from extracted documentation code to original code
 type RangesMap = BTreeMap<TextSize, TextSize>;
 
+const RUSTDOC_FENCE: &'static str = "```";
+const RUSTDOC_FENCE_TOKENS: &[&'static str] =
+    &["", "rust", "should_panic", "ignore", "no_run", "compile_fail", "edition2015", "edition2018"];
+
 /// Extracts Rust code from documentation comments as well as a mapping from
 /// the extracted source code back to the original source ranges.
 /// Lastly, a vector of new comment highlight ranges (spanning only the
@@ -67,6 +71,7 @@ pub(super) fn extract_doc_comments(
     // Mapping from extracted documentation code to original code
     let mut range_mapping: RangesMap = BTreeMap::new();
     let mut line_start = TextSize::try_from(prefix.len()).unwrap();
+    let mut is_codeblock = false;
     let mut is_doctest = false;
     // Replace the original, line-spanning comment ranges by new, only comment-prefix
     // spanning comment ranges.
@@ -76,8 +81,13 @@ pub(super) fn extract_doc_comments(
         .filter_map(|el| el.into_token().and_then(ast::Comment::cast))
         .filter(|comment| comment.kind().doc.is_some())
         .filter(|comment| {
-            if comment.text().contains("```") {
-                is_doctest = !is_doctest;
+            if let Some(idx) = comment.text().find(RUSTDOC_FENCE) {
+                is_codeblock = !is_codeblock;
+                // Check whether code is rust by inspecting fence guards
+                let guards = &comment.text()[idx + RUSTDOC_FENCE.len()..];
+                let is_rust =
+                    guards.split(',').all(|sub| RUSTDOC_FENCE_TOKENS.contains(&sub.trim()));
+                is_doctest = is_codeblock && is_rust;
                 false
             } else {
                 is_doctest
@@ -137,7 +147,7 @@ pub(super) fn highlight_doc_comment(
     let (analysis, tmp_file_id) = Analysis::from_single_file(text);
 
     stack.push();
-    for mut h in analysis.highlight(tmp_file_id).unwrap() {
+    for mut h in analysis.with_db(|db| super::highlight(db, tmp_file_id, None, true)).unwrap() {
         // Determine start offset and end offset in case of multi-line ranges
         let mut start_offset = None;
         let mut end_offset = None;
diff --git a/crates/ra_ide/src/syntax_highlighting/tags.rs b/crates/ra_ide/src/syntax_highlighting/tags.rs
index 94f466966..400d22fb6 100644
--- a/crates/ra_ide/src/syntax_highlighting/tags.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tags.rs
@@ -23,6 +23,7 @@ pub enum HighlightTag {
     Constant,
     Enum,
     EnumVariant,
+    EscapeSequence,
     Field,
     FormatSpecifier,
     Function,
@@ -71,6 +72,7 @@ impl HighlightTag {
             HighlightTag::Constant => "constant",
             HighlightTag::Enum => "enum",
             HighlightTag::EnumVariant => "enum_variant",
+            HighlightTag::EscapeSequence => "escape_sequence",
             HighlightTag::Field => "field",
             HighlightTag::FormatSpecifier => "format_specifier",
             HighlightTag::Function => "function",
diff --git a/crates/ra_ide/src/syntax_highlighting/tests.rs b/crates/ra_ide/src/syntax_highlighting/tests.rs
index 949bf59a0..b4d56a7a0 100644
--- a/crates/ra_ide/src/syntax_highlighting/tests.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tests.rs
@@ -43,6 +43,12 @@ def_fn! {
     }
 }
 
+macro_rules! noop {
+    ($expr:expr) => {
+        $expr
+    }
+}
+
 // comment
 fn main() {
     println!("Hello, {}!", 92);
@@ -61,6 +67,8 @@ fn main() {
         // Do nothing
     }
 
+    noop!(noop!(1));
+
     let mut x = 42;
     let y = &mut x;
     let z = &y;
@@ -238,6 +246,10 @@ fn main() {
 
     println!(r"Hello, {}!", "world");
 
+    // escape sequences
+    println!("Hello\nWorld");
+    println!("\u{48}\x65\x6C\x6C\x6F World");
+
     println!("{\x41}", A = 92);
     println!("{ничоси}", ничоси = 92);
 }"#
@@ -279,7 +291,13 @@ fn main() {
 fn test_highlight_doctest() {
     check_highlighting(
         r#"
+struct Foo {
+    bar: bool,
+}
+
 impl Foo {
+    pub const bar: bool = true;
+
     /// Constructs a new `Foo`.
     ///
     /// # Examples
@@ -289,7 +307,7 @@ impl Foo {
     /// let mut foo: Foo = Foo::new();
     /// ```
     pub const fn new() -> Foo {
-        Foo { }
+        Foo { bar: true }
     }
 
     /// `bar` method on `Foo`.
@@ -297,11 +315,15 @@ impl Foo {
     /// # Examples
     ///
     /// ```
+    /// use x::y;
+    ///
     /// let foo = Foo::new();
     ///
     /// // calls bar on foo
     /// assert!(foo.bar());
     ///
+    /// let bar = foo.bar || Foo::bar;
+    ///
     /// /* multi-line
     ///        comment */
     ///
@@ -311,9 +333,13 @@ impl Foo {
     ///
     /// ```
     ///
-    /// ```
+    /// ```rust,no_run
     /// let foobar = Foo::new().bar();
     /// ```
+    ///
+    /// ```sh
+    /// echo 1
+    /// ```
     pub fn foo(&self) -> bool {
         true
     }
@@ -322,7 +348,7 @@ impl Foo {
         .trim(),
         "crates/ra_ide/src/snapshots/highlight_doctest.html",
         false,
-    )
+    );
 }
 
 /// Highlights the code given by the `ra_fixture` argument, renders the