13 files changed, 66 insertions, 5 deletions

diff --git a/crates/assists/src/ast_transform.rs b/crates/assists/src/ast_transform.rs
index da94e9987..4a3ed7783 100644
--- a/crates/assists/src/ast_transform.rs
+++ b/crates/assists/src/ast_transform.rs
@@ -204,7 +204,8 @@ impl<'a> AstTransform<'a> for QualifyPaths<'a> {
             }
             PathResolution::Local(_)
             | PathResolution::TypeParam(_)
-            | PathResolution::SelfType(_) => None,
+            | PathResolution::SelfType(_)
+            | PathResolution::ConstParam(_) => None,
             PathResolution::Macro(_) => None,
             PathResolution::AssocItem(_) => None,
         }
diff --git a/crates/hir_ty/src/tests/simple.rs b/crates/hir_ty/src/tests/simple.rs
index bd6beea99..8d431b920 100644
--- a/crates/hir_ty/src/tests/simple.rs
+++ b/crates/hir_ty/src/tests/simple.rs
@@ -2376,7 +2376,6 @@ fn infer_operator_overload() {
     );
 }
 
-
 #[test]
 fn infer_const_params() {
     check_infer(
diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index 6431e7d6d..bcde2b6f1 100644
--- a/crates/ide/src/display/navigation_target.rs
+++ b/crates/ide/src/display/navigation_target.rs
@@ -24,6 +24,7 @@ pub enum SymbolKind {
     Impl,
     Field,
     TypeParam,
+    ConstParam,
     LifetimeParam,
     ValueParam,
     SelfParam,
@@ -225,6 +226,7 @@ impl TryToNav for Definition {
             Definition::TypeParam(it) => Some(it.to_nav(db)),
             Definition::LifetimeParam(it) => Some(it.to_nav(db)),
             Definition::Label(it) => Some(it.to_nav(db)),
+            Definition::ConstParam(it) => Some(it.to_nav(db)),
         }
     }
 }
@@ -485,6 +487,23 @@ impl ToNav for hir::LifetimeParam {
     }
 }
 
+impl ToNav for hir::ConstParam {
+    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
+        let src = self.source(db);
+        let full_range = src.value.syntax().text_range();
+        NavigationTarget {
+            file_id: src.file_id.original_file(db),
+            name: self.name(db).to_string().into(),
+            kind: Some(SymbolKind::ConstParam),
+            full_range,
+            focus_range: src.value.name().map(|n| n.syntax().text_range()),
+            container_name: None,
+            description: None,
+            docs: None,
+        }
+    }
+}
+
 /// Get a description of a symbol.
 ///
 /// e.g. `struct Name`, `enum Name`, `fn Name`
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index e10516f43..367fac05e 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -193,6 +193,7 @@ fn rewrite_intra_doc_link(
         Definition::SelfType(_)
         | Definition::Local(_)
         | Definition::TypeParam(_)
+        | Definition::ConstParam(_)
         | Definition::LifetimeParam(_)
         | Definition::Label(_) => return None,
     }?;
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 73245fbe7..49eb8caae 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -370,7 +370,10 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
                 Adt::Enum(it) => from_def_source(db, it, mod_path),
             })
         }
-        Definition::TypeParam(_) | Definition::LifetimeParam(_) | Definition::Label(_) => {
+        Definition::TypeParam(_)
+        | Definition::LifetimeParam(_)
+        | Definition::ConstParam(_)
+        | Definition::Label(_) => {
             // FIXME: Hover for generic param
             None
         }
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index 21b2d7ca1..fa58fc319 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -1144,4 +1144,20 @@ fn foo<'a>() -> &'a () {
             "#]],
         );
     }
+
+    #[test]
+    fn test_find_const_param() {
+        check(
+            r#"
+fn foo<const FOO<|>: usize>() -> usize {
+    FOO
+}
+"#,
+            expect![[r#"
+                FOO ConstParam FileId(0) 7..23 13..16 Other
+
+                FileId(0) 42..45 Other
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 5ad96581b..ba0085244 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -819,6 +819,7 @@ fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
         },
         Definition::SelfType(_) => HighlightTag::Symbol(SymbolKind::Impl),
         Definition::TypeParam(_) => HighlightTag::Symbol(SymbolKind::TypeParam),
+        Definition::ConstParam(_) => HighlightTag::Symbol(SymbolKind::ConstParam),
         Definition::Local(local) => {
             let tag = if local.is_param(db) {
                 HighlightTag::Symbol(SymbolKind::ValueParam)
diff --git a/crates/ide/src/syntax_highlighting/tags.rs b/crates/ide/src/syntax_highlighting/tags.rs
index 2a6cc0cab..8b8867079 100644
--- a/crates/ide/src/syntax_highlighting/tags.rs
+++ b/crates/ide/src/syntax_highlighting/tags.rs
@@ -77,6 +77,7 @@ impl HighlightTag {
                 SymbolKind::Function => "function",
                 SymbolKind::TypeAlias => "type_alias",
                 SymbolKind::TypeParam => "type_param",
+                SymbolKind::ConstParam => "const_param",
                 SymbolKind::LifetimeParam => "lifetime",
                 SymbolKind::Macro => "macro",
                 SymbolKind::Local => "variable",
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlighting.html b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
index 72ff9dd40..02270b077 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
@@ -118,6 +118,10 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="keyword control">loop</span> <span class="punctuation">{</span><span class="punctuation">}</span>
 <span class="punctuation">}</span>
 
+<span class="keyword">fn</span> <span class="function declaration">const_param</span><span class="punctuation">&lt;</span><span class="keyword">const</span> <span class="const_param declaration">FOO</span><span class="punctuation">:</span> <span class="builtin_type">usize</span><span class="punctuation">&gt;</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="builtin_type">usize</span> <span class="punctuation">{</span>
+    <span class="const_param">FOO</span>
+<span class="punctuation">}</span>
+
 <span class="keyword">use</span> <span class="module">ops</span><span class="operator">::</span><span class="trait">Fn</span><span class="punctuation">;</span>
 <span class="keyword">fn</span> <span class="function declaration">baz</span><span class="punctuation">&lt;</span><span class="type_param declaration">F</span><span class="punctuation">:</span> <span class="trait">Fn</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">&gt;</span><span class="punctuation">(</span><span class="value_param declaration callable">f</span><span class="punctuation">:</span> <span class="type_param">F</span><span class="punctuation">)</span> <span class="punctuation">{</span>
     <span class="value_param callable">f</span><span class="punctuation">(</span><span class="punctuation">)</span>
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index e0df0d2b5..30b5b648e 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -91,6 +91,10 @@ fn never() -> ! {
     loop {}
 }
 
+fn const_param<const FOO: usize>() -> usize {
+    FOO
+}
+
 use ops::Fn;
 fn baz<F: Fn() -> ()>(f: F) {
     f()
diff --git a/crates/ide_db/src/defs.rs b/crates/ide_db/src/defs.rs
index d33a6cb86..cc5078bf0 100644
--- a/crates/ide_db/src/defs.rs
+++ b/crates/ide_db/src/defs.rs
@@ -6,8 +6,8 @@
 // FIXME: this badly needs rename/rewrite (matklad, 2020-02-06).
 
 use hir::{
-    db::HirDatabase, Crate, Field, HasVisibility, Impl, Label, LifetimeParam, Local, MacroDef,
-    Module, ModuleDef, Name, PathResolution, Semantics, TypeParam, Visibility,
+    db::HirDatabase, ConstParam, Crate, Field, HasVisibility, Impl, Label, LifetimeParam, Local,
+    MacroDef, Module, ModuleDef, Name, PathResolution, Semantics, TypeParam, Visibility,
 };
 use syntax::{
     ast::{self, AstNode},
@@ -26,6 +26,7 @@ pub enum Definition {
     Local(Local),
     TypeParam(TypeParam),
     LifetimeParam(LifetimeParam),
+    ConstParam(ConstParam),
     Label(Label),
 }
 
@@ -39,6 +40,7 @@ impl Definition {
             Definition::Local(it) => Some(it.module(db)),
             Definition::TypeParam(it) => Some(it.module(db)),
             Definition::LifetimeParam(it) => Some(it.module(db)),
+            Definition::ConstParam(it) => Some(it.module(db)),
             Definition::Label(it) => Some(it.module(db)),
         }
     }
@@ -52,6 +54,7 @@ impl Definition {
             Definition::Local(_) => None,
             Definition::TypeParam(_) => None,
             Definition::LifetimeParam(_) => None,
+            Definition::ConstParam(_) => None,
             Definition::Label(_) => None,
         }
     }
@@ -79,6 +82,7 @@ impl Definition {
             Definition::Local(it) => it.name(db)?,
             Definition::TypeParam(it) => it.name(db),
             Definition::LifetimeParam(it) => it.name(db),
+            Definition::ConstParam(it) => it.name(db),
             Definition::Label(it) => it.name(db),
         };
         Some(name)
@@ -233,6 +237,10 @@ impl NameClass {
                     let def = sema.to_def(&it)?;
                     Some(NameClass::Definition(Definition::TypeParam(def)))
                 },
+                ast::ConstParam(it) => {
+                    let def = sema.to_def(&it)?;
+                    Some(NameClass::Definition(Definition::ConstParam(def)))
+                },
                 _ => None,
             }
         }
@@ -417,6 +425,7 @@ impl From<PathResolution> for Definition {
             PathResolution::TypeParam(par) => Definition::TypeParam(par),
             PathResolution::Macro(def) => Definition::Macro(def),
             PathResolution::SelfType(impl_def) => Definition::SelfType(impl_def),
+            PathResolution::ConstParam(par) => Definition::ConstParam(par),
         }
     }
 }
diff --git a/crates/rust-analyzer/src/semantic_tokens.rs b/crates/rust-analyzer/src/semantic_tokens.rs
index c2f6a655d..5c4366f16 100644
--- a/crates/rust-analyzer/src/semantic_tokens.rs
+++ b/crates/rust-analyzer/src/semantic_tokens.rs
@@ -44,6 +44,7 @@ define_semantic_token_types![
     (ESCAPE_SEQUENCE, "escapeSequence"),
     (FORMAT_SPECIFIER, "formatSpecifier"),
     (GENERIC, "generic"),
+    (CONST_PARAMETER, "constParameter"),
     (LIFETIME, "lifetime"),
     (LABEL, "label"),
     (PUNCTUATION, "punctuation"),
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 1a38e79f0..999b18351 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -42,6 +42,7 @@ pub(crate) fn symbol_kind(symbol_kind: SymbolKind) -> lsp_types::SymbolKind {
         SymbolKind::Field => lsp_types::SymbolKind::Field,
         SymbolKind::Static => lsp_types::SymbolKind::Constant,
         SymbolKind::Const => lsp_types::SymbolKind::Constant,
+        SymbolKind::ConstParam => lsp_types::SymbolKind::Constant,
         SymbolKind::Impl => lsp_types::SymbolKind::Object,
         SymbolKind::Local
         | SymbolKind::SelfParam
@@ -378,6 +379,7 @@ fn semantic_token_type_and_modifiers(
             SymbolKind::Impl => lsp_types::SemanticTokenType::TYPE,
             SymbolKind::Field => lsp_types::SemanticTokenType::PROPERTY,
             SymbolKind::TypeParam => lsp_types::SemanticTokenType::TYPE_PARAMETER,
+            SymbolKind::ConstParam => semantic_tokens::CONST_PARAMETER,
             SymbolKind::LifetimeParam => semantic_tokens::LIFETIME,
             SymbolKind::Label => semantic_tokens::LABEL,
             SymbolKind::ValueParam => lsp_types::SemanticTokenType::PARAMETER,