17 files changed, 214 insertions, 98 deletions

diff --git a/crates/ide/Cargo.toml b/crates/ide/Cargo.toml
index f1544dbe0..bb28cca4d 100644
--- a/crates/ide/Cargo.toml
+++ b/crates/ide/Cargo.toml
@@ -36,4 +36,4 @@ completion = { path = "../completion", version = "0.0.0" }
 hir = { path = "../hir", version = "0.0.0" }
 
 [dev-dependencies]
-expect-test = "1.0"
+expect-test = "1.1"
diff --git a/crates/ide/src/call_hierarchy.rs b/crates/ide/src/call_hierarchy.rs
index 60e0cd4ad..3c2d39f5d 100644
--- a/crates/ide/src/call_hierarchy.rs
+++ b/crates/ide/src/call_hierarchy.rs
@@ -8,7 +8,7 @@ use ide_db::RootDatabase;
 use syntax::{ast, match_ast, AstNode, TextRange};
 
 use crate::{
-    display::ToNav, goto_definition, references, FilePosition, NavigationTarget, RangeInfo,
+    display::TryToNav, goto_definition, references, FilePosition, NavigationTarget, RangeInfo,
 };
 
 #[derive(Debug, Clone)]
@@ -61,7 +61,7 @@ pub(crate) fn incoming_calls(db: &RootDatabase, position: FilePosition) -> Optio
                 match node {
                     ast::Fn(it) => {
                         let def = sema.to_def(&it)?;
-                        Some(def.to_nav(sema.db))
+                        def.try_to_nav(sema.db)
                     },
                     _ => None,
                 }
@@ -99,7 +99,7 @@ pub(crate) fn outgoing_calls(db: &RootDatabase, position: FilePosition) -> Optio
                     match callable.kind() {
                         hir::CallableKind::Function(it) => {
                             let fn_def: hir::Function = it.into();
-                            let nav = fn_def.to_nav(db);
+                            let nav = fn_def.try_to_nav(db)?;
                             Some(nav)
                         }
                         _ => None,
@@ -107,7 +107,7 @@ pub(crate) fn outgoing_calls(db: &RootDatabase, position: FilePosition) -> Optio
                 }
                 FnCallNode::MethodCallExpr(expr) => {
                     let function = sema.resolve_method_call(&expr)?;
-                    Some(function.to_nav(db))
+                    function.try_to_nav(db)
                 }
             } {
                 Some((func_target, name_ref.syntax().text_range()))
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index d79f5c170..ec0f840e9 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -156,20 +156,23 @@ fn missing_record_expr_field_fix(
     let record_fields = match VariantDef::from(def_id) {
         VariantDef::Struct(s) => {
             module = s.module(sema.db);
-            let source = s.source(sema.db);
+            #[allow(deprecated)]
+            let source = s.source(sema.db)?;
             def_file_id = source.file_id;
             let fields = source.value.field_list()?;
             record_field_list(fields)?
         }
         VariantDef::Union(u) => {
             module = u.module(sema.db);
-            let source = u.source(sema.db);
+            #[allow(deprecated)]
+            let source = u.source(sema.db)?;
             def_file_id = source.file_id;
             source.value.record_field_list()?
         }
         VariantDef::Variant(e) => {
             module = e.module(sema.db);
-            let source = e.source(sema.db);
+            #[allow(deprecated)]
+            let source = e.source(sema.db)?;
             def_file_id = source.file_id;
             let fields = source.value.field_list()?;
             record_field_list(fields)?
diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index 6431e7d6d..e24c78301 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,
@@ -209,40 +210,32 @@ impl ToNav for FileSymbol {
 impl TryToNav for Definition {
     fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
         match self {
-            Definition::Macro(it) => {
-                // FIXME: Currently proc-macro do not have ast-node,
-                // such that it does not have source
-                // more discussion: https://github.com/rust-analyzer/rust-analyzer/issues/6913
-                if it.is_proc_macro() {
-                    return None;
-                }
-                Some(it.to_nav(db))
-            }
-            Definition::Field(it) => Some(it.to_nav(db)),
+            Definition::Macro(it) => it.try_to_nav(db),
+            Definition::Field(it) => it.try_to_nav(db),
             Definition::ModuleDef(it) => it.try_to_nav(db),
-            Definition::SelfType(it) => Some(it.to_nav(db)),
+            Definition::SelfType(it) => it.try_to_nav(db),
             Definition::Local(it) => Some(it.to_nav(db)),
-            Definition::TypeParam(it) => Some(it.to_nav(db)),
-            Definition::LifetimeParam(it) => Some(it.to_nav(db)),
+            Definition::TypeParam(it) => it.try_to_nav(db),
+            Definition::LifetimeParam(it) => it.try_to_nav(db),
             Definition::Label(it) => Some(it.to_nav(db)),
+            Definition::ConstParam(it) => it.try_to_nav(db),
         }
     }
 }
 
 impl TryToNav for hir::ModuleDef {
     fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
-        let res = match self {
-            hir::ModuleDef::Module(it) => it.to_nav(db),
-            hir::ModuleDef::Function(it) => it.to_nav(db),
-            hir::ModuleDef::Adt(it) => it.to_nav(db),
-            hir::ModuleDef::Variant(it) => it.to_nav(db),
-            hir::ModuleDef::Const(it) => it.to_nav(db),
-            hir::ModuleDef::Static(it) => it.to_nav(db),
-            hir::ModuleDef::Trait(it) => it.to_nav(db),
-            hir::ModuleDef::TypeAlias(it) => it.to_nav(db),
-            hir::ModuleDef::BuiltinType(_) => return None,
-        };
-        Some(res)
+        match self {
+            hir::ModuleDef::Module(it) => Some(it.to_nav(db)),
+            hir::ModuleDef::Function(it) => it.try_to_nav(db),
+            hir::ModuleDef::Adt(it) => it.try_to_nav(db),
+            hir::ModuleDef::Variant(it) => it.try_to_nav(db),
+            hir::ModuleDef::Const(it) => it.try_to_nav(db),
+            hir::ModuleDef::Static(it) => it.try_to_nav(db),
+            hir::ModuleDef::Trait(it) => it.try_to_nav(db),
+            hir::ModuleDef::TypeAlias(it) => it.try_to_nav(db),
+            hir::ModuleDef::BuiltinType(_) => None,
+        }
     }
 }
 
@@ -277,13 +270,13 @@ impl ToNavFromAst for hir::Trait {
     const KIND: SymbolKind = SymbolKind::Trait;
 }
 
-impl<D> ToNav for D
+impl<D> TryToNav for D
 where
     D: HasSource + ToNavFromAst + Copy + HasAttrs,
     D::Ast: ast::NameOwner + ShortLabel,
 {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
-        let src = self.source(db);
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
         let mut res = NavigationTarget::from_named(
             db,
             src.as_ref().map(|it| it as &dyn ast::NameOwner),
@@ -291,7 +284,7 @@ where
         );
         res.docs = self.docs(db);
         res.description = src.value.short_label();
-        res
+        Some(res)
     }
 }
 
@@ -310,9 +303,9 @@ impl ToNav for hir::Module {
     }
 }
 
-impl ToNav for hir::Impl {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
-        let src = self.source(db);
+impl TryToNav for hir::Impl {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
         let derive_attr = self.is_builtin_derive(db);
         let frange = if let Some(item) = &derive_attr {
             item.syntax().original_file_range(db)
@@ -325,21 +318,21 @@ impl ToNav for hir::Impl {
             src.value.self_ty().map(|ty| src.with_value(ty.syntax()).original_file_range(db).range)
         };
 
-        NavigationTarget::from_syntax(
+        Some(NavigationTarget::from_syntax(
             frange.file_id,
             "impl".into(),
             focus_range,
             frange.range,
             SymbolKind::Impl,
-        )
+        ))
     }
 }
 
-impl ToNav for hir::Field {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
-        let src = self.source(db);
+impl TryToNav for hir::Field {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
 
-        match &src.value {
+        let field_source = match &src.value {
             FieldSource::Named(it) => {
                 let mut res =
                     NavigationTarget::from_named(db, src.with_value(it), SymbolKind::Field);
@@ -357,13 +350,14 @@ impl ToNav for hir::Field {
                     SymbolKind::Field,
                 )
             }
-        }
+        };
+        Some(field_source)
     }
 }
 
-impl ToNav for hir::MacroDef {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
-        let src = self.source(db);
+impl TryToNav for hir::MacroDef {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
         log::debug!("nav target {:#?}", src.value.syntax());
         let mut res = NavigationTarget::from_named(
             db,
@@ -371,26 +365,26 @@ impl ToNav for hir::MacroDef {
             SymbolKind::Macro,
         );
         res.docs = self.docs(db);
-        res
+        Some(res)
     }
 }
 
-impl ToNav for hir::Adt {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
+impl TryToNav for hir::Adt {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
         match self {
-            hir::Adt::Struct(it) => it.to_nav(db),
-            hir::Adt::Union(it) => it.to_nav(db),
-            hir::Adt::Enum(it) => it.to_nav(db),
+            hir::Adt::Struct(it) => it.try_to_nav(db),
+            hir::Adt::Union(it) => it.try_to_nav(db),
+            hir::Adt::Enum(it) => it.try_to_nav(db),
         }
     }
 }
 
-impl ToNav for hir::AssocItem {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
+impl TryToNav for hir::AssocItem {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
         match self {
-            AssocItem::Function(it) => it.to_nav(db),
-            AssocItem::Const(it) => it.to_nav(db),
-            AssocItem::TypeAlias(it) => it.to_nav(db),
+            AssocItem::Function(it) => it.try_to_nav(db),
+            AssocItem::Const(it) => it.try_to_nav(db),
+            AssocItem::TypeAlias(it) => it.try_to_nav(db),
         }
     }
 }
@@ -444,9 +438,9 @@ impl ToNav for hir::Label {
     }
 }
 
-impl ToNav for hir::TypeParam {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
-        let src = self.source(db);
+impl TryToNav for hir::TypeParam {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
         let full_range = match &src.value {
             Either::Left(it) => it.syntax().text_range(),
             Either::Right(it) => it.syntax().text_range(),
@@ -455,7 +449,7 @@ impl ToNav for hir::TypeParam {
             Either::Left(_) => None,
             Either::Right(it) => it.name().map(|it| it.syntax().text_range()),
         };
-        NavigationTarget {
+        Some(NavigationTarget {
             file_id: src.file_id.original_file(db),
             name: self.name(db).to_string().into(),
             kind: Some(SymbolKind::TypeParam),
@@ -464,15 +458,15 @@ impl ToNav for hir::TypeParam {
             container_name: None,
             description: None,
             docs: None,
-        }
+        })
     }
 }
 
-impl ToNav for hir::LifetimeParam {
-    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
-        let src = self.source(db);
+impl TryToNav for hir::LifetimeParam {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
         let full_range = src.value.syntax().text_range();
-        NavigationTarget {
+        Some(NavigationTarget {
             file_id: src.file_id.original_file(db),
             name: self.name(db).to_string().into(),
             kind: Some(SymbolKind::LifetimeParam),
@@ -481,7 +475,24 @@ impl ToNav for hir::LifetimeParam {
             container_name: None,
             description: None,
             docs: None,
-        }
+        })
+    }
+}
+
+impl TryToNav for hir::ConstParam {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        let src = self.source(db)?;
+        let full_range = src.value.syntax().text_range();
+        Some(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,
+        })
     }
 }
 
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/goto_implementation.rs b/crates/ide/src/goto_implementation.rs
index 6eac39639..da9378a97 100644
--- a/crates/ide/src/goto_implementation.rs
+++ b/crates/ide/src/goto_implementation.rs
@@ -2,7 +2,7 @@ use hir::{Crate, Impl, Semantics};
 use ide_db::RootDatabase;
 use syntax::{algo::find_node_at_offset, ast, AstNode};
 
-use crate::{display::ToNav, FilePosition, NavigationTarget, RangeInfo};
+use crate::{display::TryToNav, FilePosition, NavigationTarget, RangeInfo};
 
 // Feature: Go to Implementation
 //
@@ -55,7 +55,7 @@ fn impls_for_def(
         impls
             .into_iter()
             .filter(|impl_def| ty.is_equal_for_find_impls(&impl_def.target_ty(sema.db)))
-            .map(|imp| imp.to_nav(sema.db))
+            .filter_map(|imp| imp.try_to_nav(sema.db))
             .collect(),
     )
 }
@@ -69,7 +69,7 @@ fn impls_for_trait(
 
     let impls = Impl::for_trait(sema.db, krate, tr);
 
-    Some(impls.into_iter().map(|imp| imp.to_nav(sema.db)).collect())
+    Some(impls.into_iter().filter_map(|imp| imp.try_to_nav(sema.db)).collect())
 }
 
 #[cfg(test)]
diff --git a/crates/ide/src/goto_type_definition.rs b/crates/ide/src/goto_type_definition.rs
index aba6bf5dc..7e84e06be 100644
--- a/crates/ide/src/goto_type_definition.rs
+++ b/crates/ide/src/goto_type_definition.rs
@@ -1,7 +1,7 @@
 use ide_db::RootDatabase;
 use syntax::{ast, match_ast, AstNode, SyntaxKind::*, SyntaxToken, TokenAtOffset, T};
 
-use crate::{display::ToNav, FilePosition, NavigationTarget, RangeInfo};
+use crate::{display::TryToNav, FilePosition, NavigationTarget, RangeInfo};
 
 // Feature: Go to Type Definition
 //
@@ -37,7 +37,7 @@ pub(crate) fn goto_type_definition(
 
     let adt_def = ty.autoderef(db).filter_map(|ty| ty.as_adt()).last()?;
 
-    let nav = adt_def.to_nav(db);
+    let nav = adt_def.try_to_nav(db)?;
     Some(RangeInfo::new(node.text_range(), vec![nav]))
 }
 
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 73245fbe7..2737c900f 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -13,7 +13,7 @@ use syntax::{ast, match_ast, AstNode, SyntaxKind::*, SyntaxToken, TokenAtOffset,
 use test_utils::mark;
 
 use crate::{
-    display::{macro_label, ShortLabel, ToNav, TryToNav},
+    display::{macro_label, ShortLabel, TryToNav},
     doc_links::{remove_links, rewrite_links},
     markdown_remove::remove_markdown,
     markup::Markup,
@@ -109,6 +109,8 @@ pub(crate) fn hover(
         match node {
             ast::Name(name) => NameClass::classify(&sema, &name).and_then(|d| d.defined(sema.db)),
             ast::NameRef(name_ref) => NameRefClass::classify(&sema, &name_ref).map(|d| d.referenced(sema.db)),
+            ast::Lifetime(lifetime) => NameClass::classify_lifetime(&sema, &lifetime)
+                .map_or_else(|| NameRefClass::classify_lifetime(&sema, &lifetime).map(|d| d.referenced(sema.db)), |d| d.defined(sema.db)),
             _ => None,
         }
     };
@@ -181,10 +183,10 @@ fn show_implementations_action(db: &RootDatabase, def: Definition) -> Option<Hov
 
     match def {
         Definition::ModuleDef(it) => match it {
-            ModuleDef::Adt(Adt::Struct(it)) => Some(to_action(it.to_nav(db))),
-            ModuleDef::Adt(Adt::Union(it)) => Some(to_action(it.to_nav(db))),
-            ModuleDef::Adt(Adt::Enum(it)) => Some(to_action(it.to_nav(db))),
-            ModuleDef::Trait(it) => Some(to_action(it.to_nav(db))),
+            ModuleDef::Adt(Adt::Struct(it)) => Some(to_action(it.try_to_nav(db)?)),
+            ModuleDef::Adt(Adt::Union(it)) => Some(to_action(it.try_to_nav(db)?)),
+            ModuleDef::Adt(Adt::Enum(it)) => Some(to_action(it.try_to_nav(db)?)),
+            ModuleDef::Trait(it) => Some(to_action(it.try_to_nav(db)?)),
             _ => None,
         },
         _ => None,
@@ -204,7 +206,8 @@ fn runnable_action(
                 _ => None,
             },
             ModuleDef::Function(it) => {
-                let src = it.source(sema.db);
+                #[allow(deprecated)]
+                let src = it.source(sema.db)?;
                 if src.file_id != file_id.into() {
                     mark::hit!(hover_macro_generated_struct_fn_doc_comment);
                     mark::hit!(hover_macro_generated_struct_fn_doc_attr);
@@ -324,17 +327,12 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
     let mod_path = definition_mod_path(db, &def);
     return match def {
         Definition::Macro(it) => {
-            // FIXME: Currently proc-macro do not have ast-node,
-            // such that it does not have source
-            // more discussion: https://github.com/rust-analyzer/rust-analyzer/issues/6913
-            if it.is_proc_macro() {
-                return None;
-            }
-            let label = macro_label(&it.source(db).value);
+            let label = macro_label(&it.source(db)?.value);
             from_def_source_labeled(db, it, Some(label), mod_path)
         }
         Definition::Field(def) => {
-            let src = def.source(db).value;
+            #[allow(deprecated)]
+            let src = def.source(db)?.value;
             if let FieldSource::Named(it) = src {
                 from_def_source_labeled(db, def, it.short_label(), mod_path)
             } else {
@@ -360,9 +358,9 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
             ModuleDef::Static(it) => from_def_source(db, it, mod_path),
             ModuleDef::Trait(it) => from_def_source(db, it, mod_path),
             ModuleDef::TypeAlias(it) => from_def_source(db, it, mod_path),
-            ModuleDef::BuiltinType(it) => return Some(it.to_string().into()),
+            ModuleDef::BuiltinType(it) => Some(Markup::fenced_block(&it)),
         },
-        Definition::Local(it) => return Some(Markup::fenced_block(&it.ty(db).display(db))),
+        Definition::Local(it) => Some(Markup::fenced_block(&it.ty(db).display(db))),
         Definition::SelfType(impl_def) => {
             impl_def.target_ty(db).as_adt().and_then(|adt| match adt {
                 Adt::Struct(it) => from_def_source(db, it, mod_path),
@@ -370,7 +368,9 @@ 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::Label(it) => Some(Markup::fenced_block(&it.name(db))),
+        Definition::LifetimeParam(it) => Some(Markup::fenced_block(&it.name(db))),
+        Definition::TypeParam(_) | Definition::ConstParam(_) => {
             // FIXME: Hover for generic param
             None
         }
@@ -381,7 +381,8 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
         D: HasSource<Ast = A> + HasAttrs + Copy,
         A: ShortLabel,
     {
-        let short_label = def.source(db).value.short_label();
+        #[allow(deprecated)]
+        let short_label = def.source(db)?.value.short_label();
         from_def_source_labeled(db, def, short_label, mod_path)
     }
 
@@ -403,7 +404,7 @@ fn pick_best(tokens: TokenAtOffset<SyntaxToken>) -> Option<SyntaxToken> {
     return tokens.max_by_key(priority);
     fn priority(n: &SyntaxToken) -> usize {
         match n.kind() {
-            IDENT | INT_NUMBER => 3,
+            IDENT | INT_NUMBER | LIFETIME_IDENT => 3,
             T!['('] | T![')'] => 2,
             kind if kind.is_trivia() => 0,
             _ => 1,
@@ -1169,7 +1170,10 @@ fn f() { fo<|>o!(); }
             r#"struct TS(String, i32<|>);"#,
             expect![[r#"
                 *i32*
+
+                ```rust
                 i32
+                ```
             "#]],
         )
     }
@@ -3221,4 +3225,36 @@ fn no_hover() {
 "#,
         );
     }
+
+    #[test]
+    fn hover_label() {
+        check(
+            r#"
+fn foo() {
+    'label<|>: loop {}
+}
+"#,
+            expect![[r#"
+            *'label*
+
+            ```rust
+            'label
+            ```
+            "#]],
+        );
+    }
+
+    #[test]
+    fn hover_lifetime() {
+        check(
+            r#"fn foo<'lifetime>(_: &'lifetime<|> ()) {}"#,
+            expect![[r#"
+            *'lifetime*
+
+            ```rust
+            'lifetime
+            ```
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index b3331f03f..a450794f3 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -31,6 +31,7 @@ mod folding_ranges;
 mod goto_definition;
 mod goto_implementation;
 mod goto_type_definition;
+mod view_hir;
 mod hover;
 mod inlay_hints;
 mod join_lines;
@@ -271,6 +272,10 @@ impl Analysis {
         self.with_db(|db| syntax_tree::syntax_tree(&db, file_id, text_range))
     }
 
+    pub fn view_hir(&self, position: FilePosition) -> Cancelable<String> {
+        self.with_db(|db| view_hir::view_hir(&db, position))
+    }
+
     pub fn expand_macro(&self, position: FilePosition) -> Cancelable<Option<ExpandedMacro>> {
         self.with_db(|db| expand_macro::expand_macro(db, position))
     }
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/runnables.rs b/crates/ide/src/runnables.rs
index 891183266..c893afc7c 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -230,7 +230,7 @@ impl TestAttr {
 
 const RUSTDOC_FENCE: &str = "```";
 const RUSTDOC_CODE_BLOCK_ATTRIBUTES_RUNNABLE: &[&str] =
-    &["", "rust", "should_panic", "edition2015", "edition2018"];
+    &["", "rust", "should_panic", "edition2015", "edition2018", "edition2021"];
 
 fn has_runnable_doc_test(attrs: &hir::Attrs) -> bool {
     attrs.docs().map_or(false, |doc| {
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/injection.rs b/crates/ide/src/syntax_highlighting/injection.rs
index 9eb184c74..6cbd683c6 100644
--- a/crates/ide/src/syntax_highlighting/injection.rs
+++ b/crates/ide/src/syntax_highlighting/injection.rs
@@ -54,8 +54,17 @@ pub(super) fn highlight_injection(
 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"];
+const RUSTDOC_FENCE_TOKENS: &[&'static str] = &[
+    "",
+    "rust",
+    "should_panic",
+    "ignore",
+    "no_run",
+    "compile_fail",
+    "edition2015",
+    "edition2018",
+    "edition2021",
+];
 
 /// Extracts Rust code from documentation comments as well as a mapping from
 /// the extracted source code back to the original source ranges.
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/src/view_hir.rs b/crates/ide/src/view_hir.rs
new file mode 100644
index 000000000..cfcfb7cfb
--- /dev/null
+++ b/crates/ide/src/view_hir.rs
@@ -0,0 +1,25 @@
+use hir::{Function, Semantics};
+use ide_db::base_db::FilePosition;
+use ide_db::RootDatabase;
+use syntax::{algo::find_node_at_offset, ast, AstNode};
+
+// Feature: View Hir
+//
+// |===
+// | Editor  | Action Name
+//
+// | VS Code | **Rust Analyzer: View Hir**
+// |===
+pub(crate) fn view_hir(db: &RootDatabase, position: FilePosition) -> String {
+    body_hir(db, position).unwrap_or("Not inside a function body".to_string())
+}
+
+fn body_hir(db: &RootDatabase, position: FilePosition) -> Option<String> {
+    let sema = Semantics::new(db);
+    let source_file = sema.parse(position.file_id);
+
+    let function = find_node_at_offset::<ast::Fn>(source_file.syntax(), position.offset)?;
+
+    let function: Function = sema.to_def(&function)?;
+    Some(function.debug_hir(db))
+}