Add semantic token modifier for crate root

10 files changed, 141 insertions, 14 deletions

diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index cb23fec3c7c..03d513fe4d2 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -133,6 +133,7 @@ pub struct HlRange {
 // constant:: Emitted for consts.
 // consuming:: Emitted for locals that are being consumed when use in a function call.
 // controlFlow:: Emitted for control-flow related tokens, this includes the `?` operator.
+// crateRoot:: Emitted for crate names, like `serde` and `crate`.
 // declaration:: Emitted for names of definitions, like `foo` in `fn foo() {}`.
 // defaultLibrary:: Emitted for items from built-in crates (std, core, alloc, test and proc_macro).
 // documentation:: Emitted for documentation comments.
diff --git a/crates/ide/src/syntax_highlighting/highlight.rs b/crates/ide/src/syntax_highlighting/highlight.rs
index 65705d303c6..d2ec3ca939d 100644
--- a/crates/ide/src/syntax_highlighting/highlight.rs
+++ b/crates/ide/src/syntax_highlighting/highlight.rs
@@ -164,8 +164,10 @@ fn token(
                     T![for] if !is_child_of_impl(&token) => h | HlMod::ControlFlow,
                     T![unsafe] => h | HlMod::Unsafe,
                     T![true] | T![false] => HlTag::BoolLiteral.into(),
-                    // self is handled as either a Name or NameRef already
-                    T![self] => return None,
+                    // crate is handled just as a token if it's in an `extern crate`
+                    T![crate] if parent_matches::<ast::ExternCrate>(&token) => h,
+                    // self, crate and super are handled as either a Name or NameRef already
+                    T![self] | T![crate] | T![super] => return None,
                     T![ref] => token
                         .parent()
                         .and_then(ast::IdentPat::cast)
@@ -283,7 +285,7 @@ fn highlight_name_ref(
                 }
             }
         };
-        let h = match name_class {
+        let mut h = match name_class {
             NameRefClass::Definition(def) => {
                 if let Definition::Local(local) = &def {
                     if let Some(name) = local.name(db) {
@@ -325,11 +327,15 @@ fn highlight_name_ref(
             }
             NameRefClass::FieldShorthand { .. } => SymbolKind::Field.into(),
         };
-        if h.tag == HlTag::Symbol(SymbolKind::Module) && name_ref.self_token().is_some() {
-            SymbolKind::SelfParam.into()
-        } else {
-            h
+        if h.tag == HlTag::Symbol(SymbolKind::Module) {
+            if name_ref.self_token().is_some() {
+                return SymbolKind::SelfParam.into();
+            }
+            if name_ref.crate_token().is_some() || name_ref.super_token().is_some() {
+                h.tag = HlTag::Keyword;
+            }
         }
+        h
     })
 }
 
@@ -393,7 +399,13 @@ fn highlight_def(
         Definition::Macro(_) => Highlight::new(HlTag::Symbol(SymbolKind::Macro)),
         Definition::Field(_) => Highlight::new(HlTag::Symbol(SymbolKind::Field)),
         Definition::ModuleDef(def) => match def {
-            hir::ModuleDef::Module(_) => Highlight::new(HlTag::Symbol(SymbolKind::Module)),
+            hir::ModuleDef::Module(module) => {
+                let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Module));
+                if module.parent(db).is_none() {
+                    h |= HlMod::CrateRoot
+                }
+                h
+            }
             hir::ModuleDef::Function(func) => {
                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
                 if let Some(item) = func.as_assoc_item(db) {
diff --git a/crates/ide/src/syntax_highlighting/tags.rs b/crates/ide/src/syntax_highlighting/tags.rs
index 0f9a99efac6..92c7fcab76f 100644
--- a/crates/ide/src/syntax_highlighting/tags.rs
+++ b/crates/ide/src/syntax_highlighting/tags.rs
@@ -55,6 +55,8 @@ pub enum HlMod {
     Consuming,
     /// Used with keywords like `if` and `break`.
     ControlFlow,
+    /// Used for crate names, like `serde`.
+    CrateRoot,
     /// Used for items from built-in crates (std, core, alloc, test and proc_macro).
     DefaultLibrary,
     /// `foo` in `fn foo(x: i32)` is a definition, `foo` in `foo(90 + 2)` is
@@ -194,6 +196,7 @@ impl HlMod {
         HlMod::Callable,
         HlMod::Consuming,
         HlMod::ControlFlow,
+        HlMod::CrateRoot,
         HlMod::DefaultLibrary,
         HlMod::Definition,
         HlMod::Documentation,
@@ -216,6 +219,7 @@ impl HlMod {
             HlMod::Callable => "callable",
             HlMod::Consuming => "consuming",
             HlMod::ControlFlow => "control",
+            HlMod::CrateRoot => "crate_root",
             HlMod::DefaultLibrary => "default_library",
             HlMod::Definition => "declaration",
             HlMod::Documentation => "documentation",
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html b/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html
new file mode 100644
index 00000000000..8b4a76453b4
--- /dev/null
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_crate_root.html
@@ -0,0 +1,64 @@
+
+<style>
+body                { margin: 0; }
+pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4em; }
+
+.lifetime           { color: #DFAF8F; font-style: italic; }
+.label              { color: #DFAF8F; font-style: italic; }
+.comment            { color: #7F9F7F; }
+.documentation      { color: #629755; }
+.intra_doc_link     { font-style: italic; }
+.injected           { opacity: 0.65 ; }
+.struct, .enum      { color: #7CB8BB; }
+.enum_variant       { color: #BDE0F3; }
+.string_literal     { color: #CC9393; }
+.field              { color: #94BFF3; }
+.function           { color: #93E0E3; }
+.function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
+.operator.unsafe    { color: #BC8383; }
+.mutable.unsafe     { color: #BC8383; text-decoration: underline; }
+.keyword.unsafe     { color: #BC8383; font-weight: bold; }
+.parameter          { color: #94BFF3; }
+.text               { color: #DCDCCC; }
+.type               { color: #7CB8BB; }
+.builtin_type       { color: #8CD0D3; }
+.type_param         { color: #DFAF8F; }
+.attribute          { color: #94BFF3; }
+.numeric_literal    { color: #BFEBBF; }
+.bool_literal       { color: #BFE6EB; }
+.macro              { color: #94BFF3; }
+.module             { color: #AFD8AF; }
+.value_param        { color: #DCDCCC; }
+.variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
+.mutable            { text-decoration: underline; }
+.escape_sequence    { color: #94BFF3; }
+.keyword            { color: #F0DFAF; font-weight: bold; }
+.control            { font-style: italic; }
+.reference          { font-style: italic; font-weight: bold; }
+
+.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+</style>
+<pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root library">foo</span><span class="semicolon">;</span>
+<span class="keyword">use</span> <span class="module crate_root default_library library">core</span><span class="operator">::</span><span class="module default_library library">iter</span><span class="semicolon">;</span>
+
+<span class="keyword">pub</span> <span class="keyword">const</span> <span class="constant declaration public">NINETY_TWO</span><span class="colon">:</span> <span class="builtin_type">u8</span> <span class="operator">=</span> <span class="numeric_literal">92</span><span class="semicolon">;</span>
+
+<span class="keyword">use</span> <span class="module crate_root library">foo</span> <span class="keyword">as</span> <span class="module crate_root declaration library">foooo</span><span class="semicolon">;</span>
+
+<span class="keyword">pub</span><span class="parenthesis">(</span><span class="keyword crate_root">crate</span><span class="parenthesis">)</span> <span class="keyword">fn</span> <span class="function declaration">main</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
+    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="module default_library library">iter</span><span class="operator">::</span><span class="function default_library library">repeat</span><span class="parenthesis">(</span><span class="numeric_literal">92</span><span class="parenthesis">)</span><span class="semicolon">;</span>
+<span class="brace">}</span>
+
+<span class="keyword">mod</span> <span class="module declaration">bar</span> <span class="brace">{</span>
+    <span class="keyword">pub</span><span class="parenthesis">(</span><span class="keyword control">in</span> <span class="keyword crate_root">super</span><span class="parenthesis">)</span> <span class="keyword">const</span> <span class="constant declaration">FORTY_TWO</span><span class="colon">:</span> <span class="builtin_type">u8</span> <span class="operator">=</span> <span class="numeric_literal">42</span><span class="semicolon">;</span>
+
+    <span class="keyword">mod</span> <span class="module declaration">baz</span> <span class="brace">{</span>
+        <span class="keyword">use</span> <span class="keyword">super</span><span class="operator">::</span><span class="keyword crate_root">super</span><span class="operator">::</span><span class="constant public">NINETY_TWO</span><span class="semicolon">;</span>
+        <span class="keyword">use</span> <span class="keyword crate_root">crate</span><span class="operator">::</span><span class="module crate_root library">foooo</span><span class="operator">::</span><span class="struct library">Point</span><span class="semicolon">;</span>
+
+        <span class="keyword">pub</span><span class="parenthesis">(</span><span class="keyword control">in</span> <span class="keyword">super</span><span class="operator">::</span><span class="keyword crate_root">super</span><span class="parenthesis">)</span> <span class="keyword">const</span> <span class="constant declaration">TWENTY_NINE</span><span class="colon">:</span> <span class="builtin_type">u8</span> <span class="operator">=</span> <span class="numeric_literal">29</span><span class="semicolon">;</span>
+    <span class="brace">}</span>
+<span class="brace">}</span>
+</code></pre>
\ No newline at end of file
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html b/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html
index 33d3196cdb3..ea68f5f14a5 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_default_library.html
@@ -40,7 +40,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 .unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
 </style>
-<pre><code><span class="keyword">use</span> <span class="module default_library library">core</span><span class="operator">::</span><span class="module default_library library">iter</span><span class="semicolon">;</span>
+<pre><code><span class="keyword">use</span> <span class="module crate_root default_library library">core</span><span class="operator">::</span><span class="module default_library library">iter</span><span class="semicolon">;</span>
 
 <span class="keyword">fn</span> <span class="function declaration">main</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
     <span class="keyword">let</span> <span class="variable declaration">foo</span> <span class="operator">=</span> <span class="enum_variant default_library library">Some</span><span class="parenthesis">(</span><span class="numeric_literal">92</span><span class="parenthesis">)</span><span class="semicolon">;</span>
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html b/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
index 92cfa0d0a87..ca869c78be2 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
@@ -40,6 +40,6 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 .unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
 </style>
-<pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module default_library library">std</span><span class="semicolon">;</span>
-<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module default_library library">alloc</span> <span class="keyword">as</span> <span class="module default_library declaration library">abc</span><span class="semicolon">;</span>
+<pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">std</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">alloc</span> <span class="keyword">as</span> <span class="module crate_root default_library declaration library">abc</span><span class="semicolon">;</span>
 </code></pre>
\ No newline at end of file
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlighting.html b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
index 7918a962750..05e67398300 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
@@ -253,12 +253,12 @@ proc_macros::<span class="macro">mirror!</span> <span class="brace">{</span>
 <span class="brace">}</span>
 
 <span class="keyword">fn</span> <span class="function declaration">use_foo_items</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
-    <span class="keyword">let</span> <span class="variable declaration">bob</span> <span class="operator">=</span> <span class="module library">foo</span><span class="operator">::</span><span class="struct library">Person</span> <span class="brace">{</span>
+    <span class="keyword">let</span> <span class="variable declaration">bob</span> <span class="operator">=</span> <span class="module crate_root library">foo</span><span class="operator">::</span><span class="struct library">Person</span> <span class="brace">{</span>
         <span class="field library">name</span><span class="colon">:</span> <span class="string_literal">"Bob"</span><span class="comma">,</span>
-        <span class="field library">age</span><span class="colon">:</span> <span class="module library">foo</span><span class="operator">::</span><span class="module library">consts</span><span class="operator">::</span><span class="constant library">NUMBER</span><span class="comma">,</span>
+        <span class="field library">age</span><span class="colon">:</span> <span class="module crate_root library">foo</span><span class="operator">::</span><span class="module library">consts</span><span class="operator">::</span><span class="constant library">NUMBER</span><span class="comma">,</span>
     <span class="brace">}</span><span class="semicolon">;</span>
 
-    <span class="keyword">let</span> <span class="variable declaration">control_flow</span> <span class="operator">=</span> <span class="module library">foo</span><span class="operator">::</span><span class="function library">identity</span><span class="parenthesis">(</span><span class="module library">foo</span><span class="operator">::</span><span class="enum library">ControlFlow</span><span class="operator">::</span><span class="enum_variant library">Continue</span><span class="parenthesis">)</span><span class="semicolon">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">control_flow</span> <span class="operator">=</span> <span class="module crate_root library">foo</span><span class="operator">::</span><span class="function library">identity</span><span class="parenthesis">(</span><span class="module crate_root library">foo</span><span class="operator">::</span><span class="enum library">ControlFlow</span><span class="operator">::</span><span class="enum_variant library">Continue</span><span class="parenthesis">)</span><span class="semicolon">;</span>
 
     <span class="keyword control">if</span> <span class="variable">control_flow</span><span class="operator">.</span><span class="function associated consuming library">should_die</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
         foo::<span class="macro">die!</span><span class="parenthesis">(</span><span class="parenthesis">)</span><span class="semicolon">;</span>
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index e7bfbcc6040..05c80e403c5 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -777,6 +777,50 @@ fn test_extern_crate() {
 }
 
 #[test]
+fn test_crate_root() {
+    check_highlighting(
+        r#"
+        //- minicore: iterators
+        //- /main.rs crate:main deps:foo
+        extern crate foo;
+        use core::iter;
+
+        pub const NINETY_TWO: u8 = 92;
+
+        use foo as foooo;
+
+        pub(crate) fn main() {
+            let baz = iter::repeat(92);
+        }
+
+        mod bar {
+            pub(in super) const FORTY_TWO: u8 = 42;
+
+            mod baz {
+                use super::super::NINETY_TWO;
+                use crate::foooo::Point;
+
+                pub(in super::super) const TWENTY_NINE: u8 = 29;
+            }
+        }
+        //- /foo.rs crate:foo
+        struct Point {
+            x: u8,
+            y: u8,
+        }
+
+        mod inner {
+            pub(super) fn swap(p: crate::Point) -> crate::Point {
+                crate::Point { x: p.y, y: p.x }
+            }
+        }
+        "#,
+        expect_file!["./test_data/highlight_crate_root.html"],
+        false,
+    );
+}
+
+#[test]
 fn test_default_library() {
     check_highlighting(
         r#"
diff --git a/crates/rust-analyzer/src/semantic_tokens.rs b/crates/rust-analyzer/src/semantic_tokens.rs
index d5f579f11d8..3117b757285 100644
--- a/crates/rust-analyzer/src/semantic_tokens.rs
+++ b/crates/rust-analyzer/src/semantic_tokens.rs
@@ -94,6 +94,7 @@ define_semantic_token_modifiers![
     (CONSTANT, "constant"),
     (CONSUMING, "consuming"),
     (CONTROL_FLOW, "controlFlow"),
+    (CRATE_ROOT, "crateRoot"),
     (INJECTED, "injected"),
     (INTRA_DOC_LINK, "intraDocLink"),
     (LIBRARY, "library"),
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 3508fcc189e..e18298fadee 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -535,6 +535,7 @@ fn semantic_token_type_and_modifiers(
             HlMod::Callable => semantic_tokens::CALLABLE,
             HlMod::Consuming => semantic_tokens::CONSUMING,
             HlMod::ControlFlow => semantic_tokens::CONTROL_FLOW,
+            HlMod::CrateRoot => semantic_tokens::CRATE_ROOT,
             HlMod::DefaultLibrary => lsp_types::SemanticTokenModifier::DEFAULT_LIBRARY,
             HlMod::Definition => lsp_types::SemanticTokenModifier::DECLARATION,
             HlMod::Documentation => lsp_types::SemanticTokenModifier::DOCUMENTATION,