90 files changed, 2311 insertions, 1953 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 57383491a..5563fdeb2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -127,12 +127,23 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
 
 [[package]]
+name = "cargo-platform"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0226944a63d1bf35a3b5f948dd7c59e263db83695c9e8bffc4037de02e30f1d7"
+dependencies = [
+ "serde",
+]
+
+[[package]]
 name = "cargo_metadata"
-version = "0.12.0"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d5a5f7b42f606b7f23674f6f4d877628350682bc40687d3fae65679a58d55345"
+checksum = "11a47b6286279a9998588ef7050d1ebc2500c69892a557c90fe5d071c64415dc"
 dependencies = [
+ "cargo-platform",
  "semver",
+ "semver-parser",
  "serde",
  "serde_json",
 ]
@@ -262,9 +273,9 @@ dependencies = [
 
 [[package]]
 name = "const_fn"
-version = "0.4.4"
+version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd51eab21ab4fd6a3bf889e2d0958c0a6e3a61ad04260325e919e652a2a62826"
+checksum = "28b9d6de7f49e22cf97ad17fc4036ece69300032f45f78f30b4a4482cdc3f4a6"
 
 [[package]]
 name = "crc32fast"
@@ -774,9 +785,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.81"
+version = "0.2.82"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
+checksum = "89203f3fba0a3795506acaad8ebce3c80c0af93f994d5a1d7a0b1eeb23271929"
 
 [[package]]
 name = "libloading"
@@ -1134,9 +1145,9 @@ checksum = "28b9b4df73455c861d7cbf8be42f01d3b373ed7f02e378d55fa84eafc6f638b1"
 
 [[package]]
 name = "pin-project-lite"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b063f57ec186e6140e2b8b6921e5f1bd89c7356dda5b33acc5401203ca6131c"
+checksum = "e36743d754ccdf9954c2e352ce2d4b106e024c814f6499c2dadff80da9a442d8"
 
 [[package]]
 name = "proc-macro2"
@@ -1449,9 +1460,9 @@ dependencies = [
 
 [[package]]
 name = "semver-parser"
-version = "0.10.1"
+version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42ef146c2ad5e5f4b037cd6ce2ebb775401729b19a82040c1beac9d36c7d1428"
+checksum = "00b0bef5b7f9e0df16536d3961cfb6e84331c065b4066afb39768d0e319411f7"
 dependencies = [
  "pest",
 ]
@@ -1558,9 +1569,9 @@ version = "0.0.0"
 
 [[package]]
 name = "syn"
-version = "1.0.57"
+version = "1.0.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4211ce9909eb971f111059df92c45640aad50a619cf55cd76476be803c4c68e6"
+checksum = "cc60a3d73ea6594cd712d830cc1f0390fd71542d8c8cd24e70cc54cdfd5e05d5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1643,9 +1654,9 @@ checksum = "db3c46be180f1af9673ebb27bc1235396f61ef6965b3fe0dbb2e624deb604f0e"
 
 [[package]]
 name = "thread_local"
-version = "1.0.1"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
+checksum = "bb9bc092d0d51e76b2b19d9d85534ffc9ec2db959a2523cdae0697e2972cd447"
 dependencies = [
  "lazy_static",
 ]
diff --git a/crates/assists/src/handlers/remove_dbg.rs b/crates/assists/src/handlers/remove_dbg.rs
index 0320c2f12..6114091f2 100644
--- a/crates/assists/src/handlers/remove_dbg.rs
+++ b/crates/assists/src/handlers/remove_dbg.rs
@@ -1,6 +1,6 @@
 use syntax::{
     ast::{self, AstNode},
-    match_ast, SyntaxElement, SyntaxKind, TextRange, TextSize, T,
+    match_ast, SyntaxElement, TextRange, TextSize, T,
 };
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
@@ -136,14 +136,14 @@ fn needs_parentheses_around_macro_contents(macro_contents: Vec<SyntaxElement>) -
             symbol_kind => {
                 let symbol_not_in_bracket = unpaired_brackets_in_contents.is_empty();
                 if symbol_not_in_bracket
-                    && symbol_kind != SyntaxKind::COLON // paths
-                    && (symbol_kind != SyntaxKind::DOT // field/method access
+                    && symbol_kind != T![:] // paths
+                    && (symbol_kind != T![.] // field/method access
                         || macro_contents // range expressions consist of two SyntaxKind::Dot in macro invocations
                             .peek()
-                            .map(|element| element.kind() == SyntaxKind::DOT)
+                            .map(|element| element.kind() == T![.])
                             .unwrap_or(false))
-                    && symbol_kind != SyntaxKind::QUESTION // try operator
-                    && (symbol_kind.is_punct() || symbol_kind == SyntaxKind::AS_KW)
+                    && symbol_kind != T![?] // try operator
+                    && (symbol_kind.is_punct() || symbol_kind == T![as])
                 {
                     return true;
                 }
diff --git a/crates/completion/src/completions/attribute.rs b/crates/completion/src/completions/attribute.rs
index 3a29b5203..e5522980d 100644
--- a/crates/completion/src/completions/attribute.rs
+++ b/crates/completion/src/completions/attribute.rs
@@ -5,7 +5,7 @@
 
 use itertools::Itertools;
 use rustc_hash::FxHashSet;
-use syntax::{ast, AstNode, SyntaxKind};
+use syntax::{ast, AstNode, T};
 
 use crate::{
     context::CompletionContext,
@@ -21,15 +21,17 @@ pub(crate) fn complete_attribute(acc: &mut Completions, ctx: &CompletionContext)
 
     let attribute = ctx.attribute_under_caret.as_ref()?;
     match (attribute.path(), attribute.token_tree()) {
-        (Some(path), Some(token_tree)) => match path.to_string().as_str() {
-            "derive" => complete_derive(acc, ctx, token_tree),
-            "feature" => complete_lint(acc, ctx, token_tree, FEATURES),
-            "allow" | "warn" | "deny" | "forbid" => {
+        (Some(path), Some(token_tree)) => {
+            let path = path.syntax().text();
+            if path == "derive" {
+                complete_derive(acc, ctx, token_tree)
+            } else if path == "feature" {
+                complete_lint(acc, ctx, token_tree, FEATURES)
+            } else if path == "allow" || path == "warn" || path == "deny" || path == "forbid" {
                 complete_lint(acc, ctx, token_tree.clone(), DEFAULT_LINT_COMPLETIONS);
                 complete_lint(acc, ctx, token_tree, CLIPPY_LINTS);
             }
-            _ => {}
-        },
+        }
         (_, Some(_token_tree)) => {}
         _ => complete_attribute_start(acc, ctx, attribute),
     }
@@ -203,8 +205,7 @@ fn complete_lint(
 fn parse_comma_sep_input(derive_input: ast::TokenTree) -> Result<FxHashSet<String>, ()> {
     match (derive_input.left_delimiter_token(), derive_input.right_delimiter_token()) {
         (Some(left_paren), Some(right_paren))
-            if left_paren.kind() == SyntaxKind::L_PAREN
-                && right_paren.kind() == SyntaxKind::R_PAREN =>
+            if left_paren.kind() == T!['('] && right_paren.kind() == T![')'] =>
         {
             let mut input_derives = FxHashSet::default();
             let mut current_derive = String::new();
@@ -216,7 +217,7 @@ fn parse_comma_sep_input(derive_input: ast::TokenTree) -> Result<FxHashSet<Strin
                 .skip(1)
                 .take_while(|token| token != &right_paren)
             {
-                if SyntaxKind::COMMA == token.kind() {
+                if T![,] == token.kind() {
                     if !current_derive.is_empty() {
                         input_derives.insert(current_derive);
                         current_derive = String::new();
diff --git a/crates/completion/src/completions/postfix.rs b/crates/completion/src/completions/postfix.rs
index 87f0c0b2a..9c34ed0b6 100644
--- a/crates/completion/src/completions/postfix.rs
+++ b/crates/completion/src/completions/postfix.rs
@@ -35,11 +35,14 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         None => return,
     };
 
+    let ref_removed_ty =
+        std::iter::successors(Some(receiver_ty.clone()), |ty| ty.remove_ref()).last().unwrap();
+
     let cap = match ctx.config.snippet_cap {
         Some(it) => it,
         None => return,
     };
-    let try_enum = TryEnum::from_ty(&ctx.sema, &receiver_ty);
+    let try_enum = TryEnum::from_ty(&ctx.sema, &ref_removed_ty);
     if let Some(try_enum) = &try_enum {
         match try_enum {
             TryEnum::Result => {
@@ -496,6 +499,27 @@ fn main() {
     fn postfix_completion_for_references() {
         check_edit("dbg", r#"fn main() { &&42.$0 }"#, r#"fn main() { dbg!(&&42) }"#);
         check_edit("refm", r#"fn main() { &&42.$0 }"#, r#"fn main() { &&&mut 42 }"#);
+        check_edit(
+            "ifl",
+            r#"
+enum Option<T> { Some(T), None }
+
+fn main() {
+    let bar = &Option::Some(true);
+    bar.$0
+}
+"#,
+            r#"
+enum Option<T> { Some(T), None }
+
+fn main() {
+    let bar = &Option::Some(true);
+    if let Some($1) = bar {
+    $0
+}
+}
+"#,
+        )
     }
 
     #[test]
diff --git a/crates/completion/src/completions/trait_impl.rs b/crates/completion/src/completions/trait_impl.rs
index aa9c845da..135ae49dc 100644
--- a/crates/completion/src/completions/trait_impl.rs
+++ b/crates/completion/src/completions/trait_impl.rs
@@ -93,11 +93,11 @@ fn completion_match(ctx: &CompletionContext) -> Option<(ImplCompletionKind, Synt
         // `impl .. { const $0 }`
         // ERROR      0
         //   CONST_KW <- *
-        SyntaxKind::CONST_KW => 0,
+        T![const] => 0,
         // `impl .. { fn/type $0 }`
         // FN/TYPE_ALIAS  0
         //   FN_KW        <- *
-        SyntaxKind::FN_KW | SyntaxKind::TYPE_KW => 0,
+        T![fn] | T![type] => 0,
         // `impl .. { fn/type/const foo$0 }`
         // FN/TYPE_ALIAS/CONST  1
         //  NAME                0
@@ -121,7 +121,7 @@ fn completion_match(ctx: &CompletionContext) -> Option<(ImplCompletionKind, Synt
     let impl_def = ast::Impl::cast(impl_item.parent()?.parent()?)?;
     let kind = match impl_item.kind() {
         // `impl ... { const $0 fn/type/const }`
-        _ if token.kind() == SyntaxKind::CONST_KW => ImplCompletionKind::Const,
+        _ if token.kind() == T![const] => ImplCompletionKind::Const,
         SyntaxKind::CONST | SyntaxKind::ERROR => ImplCompletionKind::Const,
         SyntaxKind::TYPE_ALIAS => ImplCompletionKind::TypeAlias,
         SyntaxKind::FN => ImplCompletionKind::Fn,
diff --git a/crates/completion/src/patterns.rs b/crates/completion/src/patterns.rs
index f148b9402..f3ce91dd1 100644
--- a/crates/completion/src/patterns.rs
+++ b/crates/completion/src/patterns.rs
@@ -5,7 +5,7 @@ use syntax::{
     ast::{self, LoopBodyOwner},
     match_ast, AstNode, Direction, NodeOrToken, SyntaxElement,
     SyntaxKind::*,
-    SyntaxNode, SyntaxToken,
+    SyntaxNode, SyntaxToken, T,
 };
 
 #[cfg(test)]
@@ -119,7 +119,7 @@ pub(crate) fn unsafe_is_prev(element: SyntaxElement) -> bool {
     element
         .into_token()
         .and_then(|it| previous_non_trivia_token(it))
-        .filter(|it| it.kind() == UNSAFE_KW)
+        .filter(|it| it.kind() == T![unsafe])
         .is_some()
 }
 #[test]
@@ -131,7 +131,7 @@ pub(crate) fn if_is_prev(element: SyntaxElement) -> bool {
     element
         .into_token()
         .and_then(|it| previous_non_trivia_token(it))
-        .filter(|it| it.kind() == IF_KW)
+        .filter(|it| it.kind() == T![if])
         .is_some()
 }
 
@@ -139,7 +139,7 @@ pub(crate) fn fn_is_prev(element: SyntaxElement) -> bool {
     element
         .into_token()
         .and_then(|it| previous_non_trivia_token(it))
-        .filter(|it| it.kind() == FN_KW)
+        .filter(|it| it.kind() == T![fn])
         .is_some()
 }
 #[test]
@@ -154,7 +154,7 @@ pub(crate) fn for_is_prev2(element: SyntaxElement) -> bool {
         .into_token()
         .and_then(|it| previous_non_trivia_token(it))
         .and_then(|it| previous_non_trivia_token(it))
-        .filter(|it| it.kind() == FOR_KW)
+        .filter(|it| it.kind() == T![for])
         .is_some()
 }
 #[test]
diff --git a/crates/flycheck/Cargo.toml b/crates/flycheck/Cargo.toml
index 1bad64a1b..1d19c7886 100644
--- a/crates/flycheck/Cargo.toml
+++ b/crates/flycheck/Cargo.toml
@@ -12,7 +12,7 @@ doctest = false
 [dependencies]
 crossbeam-channel = "0.5.0"
 log = "0.4.8"
-cargo_metadata = "=0.12.0"
+cargo_metadata = "0.12.2"
 serde_json = "1.0.48"
 jod-thread = "0.1.1"
 
diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index cc1938333..6cbf5cecf 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -1263,6 +1263,24 @@ pub enum GenericParam {
 }
 impl_from!(TypeParam, LifetimeParam, ConstParam for GenericParam);
 
+impl GenericParam {
+    pub fn module(self, db: &dyn HirDatabase) -> Module {
+        match self {
+            GenericParam::TypeParam(it) => it.module(db),
+            GenericParam::LifetimeParam(it) => it.module(db),
+            GenericParam::ConstParam(it) => it.module(db),
+        }
+    }
+
+    pub fn name(self, db: &dyn HirDatabase) -> Name {
+        match self {
+            GenericParam::TypeParam(it) => it.name(db),
+            GenericParam::LifetimeParam(it) => it.name(db),
+            GenericParam::ConstParam(it) => it.name(db),
+        }
+    }
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct TypeParam {
     pub(crate) id: TypeParamId,
diff --git a/crates/hir/src/from_id.rs b/crates/hir/src/from_id.rs
index 3e47a5e9d..c8c5fecd7 100644
--- a/crates/hir/src/from_id.rs
+++ b/crates/hir/src/from_id.rs
@@ -1,6 +1,6 @@
 //! Utility module for converting between hir_def ids and code_model wrappers.
 //!
-//! It's unclear if we need this long-term, but it's definitelly useful while we
+//! It's unclear if we need this long-term, but it's definitely useful while we
 //! are splitting the hir.
 
 use hir_def::{
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 6be1eaade..3dc33f248 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -581,7 +581,7 @@ impl ExprCollector<'_> {
         match res.value {
             Some((mark, expansion)) => {
                 // FIXME: Statements are too complicated to recover from error for now.
-                // It is because we don't have any hygenine for local variable expansion right now.
+                // It is because we don't have any hygiene for local variable expansion right now.
                 if T::can_cast(syntax::SyntaxKind::MACRO_STMTS) && res.err.is_some() {
                     self.expander.exit(self.db, mark);
                     collector(self, None);
@@ -959,7 +959,7 @@ impl ExprCollector<'_> {
 
     fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Vec<PatId>, Option<usize>) {
         // Find the location of the `..`, if there is one. Note that we do not
-        // consider the possiblity of there being multiple `..` here.
+        // consider the possibility of there being multiple `..` here.
         let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::RestPat(_)));
         // We want to skip the `..` pattern here, since we account for it above.
         let args = args
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index 6a481769d..76f5721e5 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -1,6 +1,6 @@
 //! This module describes hir-level representation of expressions.
 //!
-//! This representaion is:
+//! This representation is:
 //!
 //! 1. Identity-based. Each expression has an `id`, so we can distinguish
 //!    between different `1` in `1 + 1`.
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index 77017e4ea..f027fd48d 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -267,7 +267,7 @@ impl DefCollector<'_> {
 
         // Resolve all indeterminate resolved imports again
         // As some of the macros will expand newly import shadowing partial resolved imports
-        // FIXME: We maybe could skip this, if we handle the Indetermine imports in `resolve_imports`
+        // FIXME: We maybe could skip this, if we handle the indeterminate imports in `resolve_imports`
         // correctly
         let partial_resolved = self.resolved_imports.iter().filter_map(|directive| {
             if let PartialResolvedImport::Indeterminate(_) = directive.status {
@@ -402,7 +402,7 @@ impl DefCollector<'_> {
 
     /// Define a proc macro
     ///
-    /// A proc macro is similar to normal macro scope, but it would not visiable in legacy textual scoped.
+    /// A proc macro is similar to normal macro scope, but it would not visible in legacy textual scoped.
     /// And unconditionally exported.
     fn define_proc_macro(&mut self, name: Name, macro_: MacroDefId) {
         self.update(
@@ -592,7 +592,7 @@ impl DefCollector<'_> {
                     // XXX: urgh, so this works by accident! Here, we look at
                     // the enum data, and, in theory, this might require us to
                     // look back at the crate_def_map, creating a cycle. For
-                    // example, `enum E { crate::some_macro!(); }`. Luckely, the
+                    // example, `enum E { crate::some_macro!(); }`. Luckily, the
                     // only kind of macro that is allowed inside enum is a
                     // `cfg_macro`, and we don't need to run name resolution for
                     // it, but this is sheer luck!
@@ -655,7 +655,7 @@ impl DefCollector<'_> {
         &mut self,
         module_id: LocalModuleId,
         resolutions: &[(Option<Name>, PerNs)],
-        // All resolutions are imported with this visibility; the visibilies in
+        // All resolutions are imported with this visibility; the visibilities in
         // the `PerNs` values are ignored and overwritten
         vis: Visibility,
         import_type: ImportType,
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index 129f1dbac..e4152a0be 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -27,7 +27,7 @@ use crate::{
 
 #[derive(Debug, Clone, Default)]
 pub struct Resolver {
-    // FIXME: all usages generally call `.rev`, so maybe reverse once in consturciton?
+    // FIXME: all usages generally call `.rev`, so maybe reverse once in construction?
     scopes: Vec<Scope>,
 }
 
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index ab2637b8c..c62086390 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -40,7 +40,7 @@ impl TokenExpander {
             // FIXME switch these to ExpandResult as well
             TokenExpander::BuiltinDerive(it) => it.expand(db, id, tt).into(),
             TokenExpander::ProcMacro(_) => {
-                // We store the result in salsa db to prevent non-determinisc behavior in
+                // We store the result in salsa db to prevent non-deterministic behavior in
                 // some proc-macro implementation
                 // See #4315 for details
                 db.expand_proc_macro(id.into()).into()
diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index a1c484fdf..107417c27 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -379,7 +379,7 @@ pub fn record_literal_missing_fields(
     id: ExprId,
     expr: &Expr,
 ) -> Option<(VariantId, Vec<LocalFieldId>, /*exhaustive*/ bool)> {
-    let (fields, exhausitve) = match expr {
+    let (fields, exhaustive) = match expr {
         Expr::RecordLit { path: _, fields, spread } => (fields, spread.is_none()),
         _ => return None,
     };
@@ -400,7 +400,7 @@ pub fn record_literal_missing_fields(
     if missed_fields.is_empty() {
         return None;
     }
-    Some((variant_def, missed_fields, exhausitve))
+    Some((variant_def, missed_fields, exhaustive))
 }
 
 pub fn record_pattern_missing_fields(
diff --git a/crates/hir_ty/src/diagnostics/match_check.rs b/crates/hir_ty/src/diagnostics/match_check.rs
index 62c329731..61c47eec8 100644
--- a/crates/hir_ty/src/diagnostics/match_check.rs
+++ b/crates/hir_ty/src/diagnostics/match_check.rs
@@ -14,7 +14,7 @@
 //! The algorithm implemented here is a modified version of the one described in
 //! <http://moscova.inria.fr/~maranget/papers/warn/index.html>.
 //! However, to save future implementors from reading the original paper, we
-//! summarise the algorithm here to hopefully save time and be a little clearer
+//! summarize the algorithm here to hopefully save time and be a little clearer
 //! (without being so rigorous).
 //!
 //! The core of the algorithm revolves about a "usefulness" check. In particular, we
@@ -132,7 +132,7 @@
 //! The algorithm is inductive (on the number of columns: i.e., components of tuple patterns).
 //! That means we're going to check the components from left-to-right, so the algorithm
 //! operates principally on the first component of the matrix and new pattern-stack `p`.
-//! This algorithm is realised in the `is_useful` function.
+//! This algorithm is realized in the `is_useful` function.
 //!
 //! Base case (`n = 0`, i.e., an empty tuple pattern):
 //! - If `P` already contains an empty pattern (i.e., if the number of patterns `m > 0`), then
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 222f61a11..9594cce8b 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -491,16 +491,16 @@ impl Ty {
     fn from_hir_path_inner(
         ctx: &TyLoweringContext<'_>,
         segment: PathSegment<'_>,
-        typable: TyDefId,
+        typeable: TyDefId,
         infer_args: bool,
     ) -> Ty {
-        let generic_def = match typable {
+        let generic_def = match typeable {
             TyDefId::BuiltinType(_) => None,
             TyDefId::AdtId(it) => Some(it.into()),
             TyDefId::TypeAliasId(it) => Some(it.into()),
         };
         let substs = substs_from_path_segment(ctx, segment, generic_def, infer_args);
-        ctx.db.ty(typable).subst(&substs)
+        ctx.db.ty(typeable).subst(&substs)
     }
 
     /// Collect generic arguments from a path into a `Substs`. See also
diff --git a/crates/ide/src/call_hierarchy.rs b/crates/ide/src/call_hierarchy.rs
index 4d8983cb2..b29d1fef9 100644
--- a/crates/ide/src/call_hierarchy.rs
+++ b/crates/ide/src/call_hierarchy.rs
@@ -5,7 +5,7 @@ use indexmap::IndexMap;
 use hir::Semantics;
 use ide_db::call_info::FnCallNode;
 use ide_db::RootDatabase;
-use syntax::{ast, match_ast, AstNode, TextRange};
+use syntax::{ast, AstNode, TextRange};
 
 use crate::{
     display::TryToNav, goto_definition, references, FilePosition, NavigationTarget, RangeInfo,
@@ -57,15 +57,9 @@ pub(crate) fn incoming_calls(db: &RootDatabase, position: FilePosition) -> Optio
 
         // This target is the containing function
         if let Some(nav) = syntax.ancestors().find_map(|node| {
-            match_ast! {
-                match node {
-                    ast::Fn(it) => {
-                        let def = sema.to_def(&it)?;
-                        def.try_to_nav(sema.db)
-                    },
-                    _ => None,
-                }
-            }
+            let fn_ = ast::Fn::cast(node)?;
+            let def = sema.to_def(&fn_)?;
+            def.try_to_nav(sema.db)
         }) {
             let relative_range = reference.file_range.range;
             calls.add(&nav, relative_range);
@@ -91,17 +85,12 @@ pub(crate) fn outgoing_calls(db: &RootDatabase, position: FilePosition) -> Optio
         .filter_map(|node| FnCallNode::with_node_exact(&node))
         .filter_map(|call_node| {
             let name_ref = call_node.name_ref()?;
-
-            if let Some(func_target) = match &call_node {
+            let func_target = match call_node {
                 FnCallNode::CallExpr(expr) => {
                     //FIXME: Type::as_callable is broken
                     let callable = sema.type_of_expr(&expr.expr()?)?.as_callable(db)?;
                     match callable.kind() {
-                        hir::CallableKind::Function(it) => {
-                            let fn_def: hir::Function = it.into();
-                            let nav = fn_def.try_to_nav(db)?;
-                            Some(nav)
-                        }
+                        hir::CallableKind::Function(it) => it.try_to_nav(db),
                         _ => None,
                     }
                 }
@@ -109,11 +98,8 @@ pub(crate) fn outgoing_calls(db: &RootDatabase, position: FilePosition) -> Optio
                     let function = sema.resolve_method_call(&expr)?;
                     function.try_to_nav(db)
                 }
-            } {
-                Some((func_target, name_ref.syntax().text_range()))
-            } else {
-                None
-            }
+            }?;
+            Some((func_target, name_ref.syntax().text_range()))
         })
         .for_each(|(nav, range)| calls.add(&nav, range));
 
diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index e24c78301..4eecae697 100644
--- a/crates/ide/src/display/navigation_target.rs
+++ b/crates/ide/src/display/navigation_target.rs
@@ -215,10 +215,8 @@ impl TryToNav for Definition {
             Definition::ModuleDef(it) => it.try_to_nav(db),
             Definition::SelfType(it) => it.try_to_nav(db),
             Definition::Local(it) => Some(it.to_nav(db)),
-            Definition::TypeParam(it) => it.try_to_nav(db),
-            Definition::LifetimeParam(it) => it.try_to_nav(db),
+            Definition::GenericParam(it) => it.try_to_nav(db),
             Definition::Label(it) => Some(it.to_nav(db)),
-            Definition::ConstParam(it) => it.try_to_nav(db),
         }
     }
 }
@@ -389,6 +387,16 @@ impl TryToNav for hir::AssocItem {
     }
 }
 
+impl TryToNav for hir::GenericParam {
+    fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
+        match self {
+            hir::GenericParam::TypeParam(it) => it.try_to_nav(db),
+            hir::GenericParam::ConstParam(it) => it.try_to_nav(db),
+            hir::GenericParam::LifetimeParam(it) => it.try_to_nav(db),
+        }
+    }
+}
+
 impl ToNav for hir::Local {
     fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
         let src = self.source(db);
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 1ff818de2..de10406bc 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -1,6 +1,6 @@
 //! Resolves and rewrites links in markdown documentation.
 
-use std::{convert::TryFrom, iter::once};
+use std::{convert::TryFrom, iter::once, ops::Range};
 
 use itertools::Itertools;
 use pulldown_cmark::{BrokenLink, CowStr, Event, InlineStr, LinkType, Options, Parser, Tag};
@@ -39,7 +39,7 @@ pub(crate) fn rewrite_links(db: &RootDatabase, markdown: &str, definition: &Defi
         if target.contains("://") {
             (target.to_string(), title.to_string())
         } else {
-            // Two posibilities:
+            // Two possibilities:
             // * path-based links: `../../module/struct.MyStruct.html`
             // * module-based links (AKA intra-doc links): `super::super::module::MyStruct`
             if let Some(rewritten) = rewrite_intra_doc_link(db, *definition, target, title) {
@@ -61,6 +61,30 @@ pub(crate) fn rewrite_links(db: &RootDatabase, markdown: &str, definition: &Defi
     out
 }
 
+pub(crate) fn extract_definitions_from_markdown(
+    markdown: &str,
+) -> Vec<(String, Option<hir::Namespace>, Range<usize>)> {
+    let mut res = vec![];
+    let mut cb = |link: BrokenLink| {
+        Some((
+            /*url*/ link.reference.to_owned().into(),
+            /*title*/ link.reference.to_owned().into(),
+        ))
+    };
+    let doc = Parser::new_with_broken_link_callback(markdown, Options::empty(), Some(&mut cb));
+    for (event, range) in doc.into_offset_iter() {
+        match event {
+            Event::Start(Tag::Link(_link_type, ref target, ref title)) => {
+                let link = if target.is_empty() { title } else { target };
+                let (link, ns) = parse_link(link);
+                res.push((link.to_string(), ns, range));
+            }
+            _ => {}
+        }
+    }
+    res
+}
+
 /// Remove all links in markdown documentation.
 pub(crate) fn remove_links(markdown: &str) -> String {
     let mut drop_link = false;
@@ -192,9 +216,7 @@ fn rewrite_intra_doc_link(
         Definition::Field(it) => it.resolve_doc_path(db, link, ns),
         Definition::SelfType(_)
         | Definition::Local(_)
-        | Definition::TypeParam(_)
-        | Definition::ConstParam(_)
-        | Definition::LifetimeParam(_)
+        | Definition::GenericParam(_)
         | Definition::Label(_) => return None,
     }?;
     let krate = resolved.module(db)?.krate();
@@ -420,7 +442,7 @@ fn get_symbol_fragment(db: &dyn HirDatabase, field_or_assoc: &FieldOrAssocItem)
                     function.as_assoc_item(db).map(|assoc| assoc.container(db)),
                     Some(AssocItemContainer::Trait(..))
                 );
-                // This distinction may get more complicated when specialisation is available.
+                // This distinction may get more complicated when specialization is available.
                 // Rustdoc makes this decision based on whether a method 'has defaultness'.
                 // Currently this is only the case for provided trait methods.
                 if is_trait_method && !function.has_body(db) {
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index 95b4cb9e3..cd4afc804 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -1,14 +1,18 @@
 use either::Either;
-use hir::Semantics;
+use hir::{HasAttrs, ModuleDef, Semantics};
 use ide_db::{
     base_db::FileId,
-    defs::{NameClass, NameRefClass},
+    defs::{Definition, NameClass, NameRefClass},
     symbol_index, RootDatabase,
 };
-use syntax::{ast, match_ast, AstNode, SyntaxKind::*, SyntaxToken, TokenAtOffset, T};
+use syntax::{
+    ast, match_ast, AstNode, AstToken, SyntaxKind::*, SyntaxToken, TextSize, TokenAtOffset, T,
+};
 
 use crate::{
     display::{ToNav, TryToNav},
+    doc_links::extract_definitions_from_markdown,
+    runnables::doc_owner_to_def,
     FilePosition, NavigationTarget, RangeInfo, SymbolKind,
 };
 
@@ -30,6 +34,10 @@ pub(crate) fn goto_definition(
     let original_token = pick_best(file.token_at_offset(position.offset))?;
     let token = sema.descend_into_macros(original_token.clone());
     let parent = token.parent();
+    if let Some(comment) = ast::Comment::cast(token.clone()) {
+        let nav = def_for_doc_comment(&sema, position, &comment)?.try_to_nav(db)?;
+        return Some(RangeInfo::new(original_token.text_range(), vec![nav]));
+    }
 
     let nav_targets = match_ast! {
         match parent {
@@ -68,11 +76,58 @@ pub(crate) fn goto_definition(
     Some(RangeInfo::new(original_token.text_range(), nav_targets))
 }
 
+fn def_for_doc_comment(
+    sema: &Semantics<RootDatabase>,
+    position: FilePosition,
+    doc_comment: &ast::Comment,
+) -> Option<hir::ModuleDef> {
+    let parent = doc_comment.syntax().parent();
+    let (link, ns) = extract_positioned_link_from_comment(position, doc_comment)?;
+
+    let def = doc_owner_to_def(sema, parent)?;
+    match def {
+        Definition::ModuleDef(def) => match def {
+            ModuleDef::Module(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::Function(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::Adt(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::Variant(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::Const(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::Static(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::Trait(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::TypeAlias(it) => it.resolve_doc_path(sema.db, &link, ns),
+            ModuleDef::BuiltinType(_) => return None,
+        },
+        Definition::Macro(it) => it.resolve_doc_path(sema.db, &link, ns),
+        Definition::Field(it) => it.resolve_doc_path(sema.db, &link, ns),
+        Definition::SelfType(_)
+        | Definition::Local(_)
+        | Definition::GenericParam(_)
+        | Definition::Label(_) => return None,
+    }
+}
+
+fn extract_positioned_link_from_comment(
+    position: FilePosition,
+    comment: &ast::Comment,
+) -> Option<(String, Option<hir::Namespace>)> {
+    let comment_range = comment.syntax().text_range();
+    let doc_comment = comment.doc_comment()?;
+    let def_links = extract_definitions_from_markdown(doc_comment);
+    let (def_link, ns, _) = def_links.iter().min_by_key(|(_, _, def_link_range)| {
+        let matched_position = comment_range.start() + TextSize::from(def_link_range.start as u32);
+        match position.offset.checked_sub(matched_position) {
+            Some(distance) => distance,
+            None => comment_range.end(),
+        }
+    })?;
+    Some((def_link.to_string(), ns.clone()))
+}
+
 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 | LIFETIME_IDENT | T![self] => 2,
+            IDENT | INT_NUMBER | LIFETIME_IDENT | T![self] | COMMENT => 2,
             kind if kind.is_trivia() => 0,
             _ => 1,
         }
@@ -1145,4 +1200,34 @@ fn foo<'foo>(_: &'foo ()) {
 }"#,
         )
     }
+
+    #[test]
+    fn goto_def_for_intra_doc_link_same_file() {
+        check(
+            r#"
+/// Blah, [`bar`](bar) .. [`foo`](foo)$0 has [`bar`](bar)
+pub fn bar() { }
+
+/// You might want to see [`std::fs::read()`] too.
+pub fn foo() { }
+     //^^^
+
+}"#,
+        )
+    }
+
+    #[test]
+    fn goto_def_for_intra_doc_link_inner() {
+        check(
+            r#"
+//- /main.rs
+mod m;
+struct S;
+     //^
+
+//- /m.rs
+//! [`super::S$0`]
+"#,
+        )
+    }
 }
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 8cb4a51d8..317b6f011 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -1,6 +1,6 @@
 use hir::{
-    Adt, AsAssocItem, AssocItemContainer, FieldSource, HasAttrs, HasSource, HirDisplay, Module,
-    ModuleDef, ModuleSource, Semantics,
+    Adt, AsAssocItem, AssocItemContainer, FieldSource, GenericParam, HasAttrs, HasSource,
+    HirDisplay, Module, ModuleDef, ModuleSource, Semantics,
 };
 use ide_db::base_db::SourceDatabase;
 use ide_db::{
@@ -17,7 +17,7 @@ use crate::{
     doc_links::{remove_links, rewrite_links},
     markdown_remove::remove_markdown,
     markup::Markup,
-    runnables::{runnable, runnable_fn},
+    runnables::{runnable_fn, runnable_mod},
     FileId, FilePosition, NavigationTarget, RangeInfo, Runnable,
 };
 
@@ -175,12 +175,7 @@ fn show_implementations_action(db: &RootDatabase, def: Definition) -> Option<Hov
         Definition::SelfType(it) => it.target_ty(db).as_adt(),
         _ => None,
     }?;
-    match adt {
-        Adt::Struct(it) => it.try_to_nav(db),
-        Adt::Union(it) => it.try_to_nav(db),
-        Adt::Enum(it) => it.try_to_nav(db),
-    }
-    .map(to_action)
+    adt.try_to_nav(db).map(to_action)
 }
 
 fn runnable_action(
@@ -192,7 +187,7 @@ fn runnable_action(
         Definition::ModuleDef(it) => match it {
             ModuleDef::Module(it) => match it.definition_source(sema.db).value {
                 ModuleSource::Module(it) => {
-                    runnable(&sema, it.syntax().clone()).map(|it| HoverAction::Runnable(it))
+                    runnable_mod(&sema, it).map(|it| HoverAction::Runnable(it))
                 }
                 _ => None,
             },
@@ -220,12 +215,12 @@ fn goto_type_action(db: &RootDatabase, def: Definition) -> Option<HoverAction> {
         }
     };
 
-    if let Definition::TypeParam(it) = def {
+    if let Definition::GenericParam(GenericParam::TypeParam(it)) = def {
         it.trait_bounds(db).into_iter().for_each(|it| push_new_def(it.into()));
     } else {
         let ty = match def {
             Definition::Local(it) => it.ty(db),
-            Definition::ConstParam(it) => it.ty(db),
+            Definition::GenericParam(GenericParam::ConstParam(it)) => it.ty(db),
             _ => return None,
         };
 
@@ -357,9 +352,11 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
             })
         }
         Definition::Label(it) => Some(Markup::fenced_block(&it.name(db))),
-        Definition::LifetimeParam(it) => Some(Markup::fenced_block(&it.name(db))),
-        Definition::TypeParam(type_param) => Some(Markup::fenced_block(&type_param.display(db))),
-        Definition::ConstParam(it) => from_def_source(db, it, None),
+        Definition::GenericParam(it) => match it {
+            GenericParam::TypeParam(it) => Some(Markup::fenced_block(&it.display(db))),
+            GenericParam::LifetimeParam(it) => Some(Markup::fenced_block(&it.name(db))),
+            GenericParam::ConstParam(it) => from_def_source(db, it, None),
+        },
     };
 
     fn from_def_source<A, D>(db: &RootDatabase, def: D, mod_path: Option<String>) -> Option<Markup>
@@ -1951,16 +1948,16 @@ struct S {
 /// Test cases:
 /// case 1.  bare URL: https://www.example.com/
 /// case 2.  inline URL with title: [example](https://www.example.com/)
-/// case 3.  code refrence: [`Result`]
-/// case 4.  code refrence but miss footnote: [`String`]
+/// case 3.  code reference: [`Result`]
+/// case 4.  code reference but miss footnote: [`String`]
 /// case 5.  autolink: <http://www.example.com/>
 /// case 6.  email address: <[email protected]>
-/// case 7.  refrence: [example][example]
+/// case 7.  reference: [example][example]
 /// case 8.  collapsed link: [example][]
 /// case 9.  shortcut link: [example]
 /// case 10. inline without URL: [example]()
-/// case 11. refrence: [foo][foo]
-/// case 12. refrence: [foo][bar]
+/// case 11. reference: [foo][foo]
+/// case 12. reference: [foo][bar]
 /// case 13. collapsed link: [foo][]
 /// case 14. shortcut link: [foo]
 /// case 15. inline without URL: [foo]()
@@ -1987,16 +1984,16 @@ pub fn fo$0o() {}
                 Test cases:
                 case 1.  bare URL: https://www.example.com/
                 case 2.  inline URL with title: [example](https://www.example.com/)
-                case 3.  code refrence: `Result`
-                case 4.  code refrence but miss footnote: `String`
+                case 3.  code reference: `Result`
+                case 4.  code reference but miss footnote: `String`
                 case 5.  autolink: http://www.example.com/
                 case 6.  email address: [email protected]
-                case 7.  refrence: example
+                case 7.  reference: example
                 case 8.  collapsed link: example
                 case 9.  shortcut link: example
                 case 10. inline without URL: example
-                case 11. refrence: foo
-                case 12. refrence: foo
+                case 11. reference: foo
+                case 12. reference: foo
                 case 13. collapsed link: foo
                 case 14. shortcut link: foo
                 case 15. inline without URL: foo
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index fe60abfc8..3e9a65d9c 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -353,9 +353,25 @@ fn is_argument_similar_to_param_name(
     }
     match get_string_representation(argument) {
         None => false,
-        Some(repr) => {
-            let argument_string = repr.trim_start_matches('_');
-            argument_string.starts_with(param_name) || argument_string.ends_with(param_name)
+        Some(argument_string) => {
+            let num_leading_underscores =
+                argument_string.bytes().take_while(|&c| c == b'_').count();
+
+            // Does the argument name begin with the parameter name? Ignore leading underscores.
+            let mut arg_bytes = argument_string.bytes().skip(num_leading_underscores);
+            let starts_with_pattern = param_name.bytes().all(
+                |expected| matches!(arg_bytes.next(), Some(actual) if expected.eq_ignore_ascii_case(&actual)),
+            );
+
+            if starts_with_pattern {
+                return true;
+            }
+
+            // Does the argument name end with the parameter name?
+            let mut arg_bytes = argument_string.bytes().skip(num_leading_underscores);
+            param_name.bytes().rev().all(
+                |expected| matches!(arg_bytes.next_back(), Some(actual) if expected.eq_ignore_ascii_case(&actual)),
+            )
         }
     }
 }
@@ -901,6 +917,9 @@ fn main() {
     twiddle(true);
     doo(true);
 
+    const TWIDDLE_UPPERCASE: bool = true;
+    twiddle(TWIDDLE_UPPERCASE);
+
     let mut param_begin: Param = Param {};
     different_order(&param_begin);
     different_order(&mut param_begin);
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index cea2a13c8..1f368cbd0 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -76,8 +76,8 @@ pub use crate::{
     references::{rename::RenameError, Declaration, ReferenceSearchResult},
     runnables::{Runnable, RunnableKind, TestId},
     syntax_highlighting::{
-        tags::{Highlight, HighlightModifier, HighlightModifiers, HighlightTag},
-        HighlightedRange,
+        tags::{Highlight, HlMod, HlMods, HlPunct, HlTag},
+        HlRange,
     },
 };
 pub use assists::{Assist, AssistConfig, AssistId, AssistKind, InsertUseConfig};
@@ -449,12 +449,12 @@ impl Analysis {
     }
 
     /// Computes syntax highlighting for the given file
-    pub fn highlight(&self, file_id: FileId) -> Cancelable<Vec<HighlightedRange>> {
+    pub fn highlight(&self, file_id: FileId) -> Cancelable<Vec<HlRange>> {
         self.with_db(|db| syntax_highlighting::highlight(db, file_id, None, false))
     }
 
     /// Computes syntax highlighting for the given file range.
-    pub fn highlight_range(&self, frange: FileRange) -> Cancelable<Vec<HighlightedRange>> {
+    pub fn highlight_range(&self, frange: FileRange) -> Cancelable<Vec<HlRange>> {
         self.with_db(|db| {
             syntax_highlighting::highlight(db, frange.file_id, Some(frange.range), false)
         })
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index c95ed669c..b774a2be1 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -3,7 +3,7 @@
 //! or `ast::NameRef`. If it's a `ast::NameRef`, at the classification step we
 //! try to resolve the direct tree parent of this element, otherwise we
 //! already have a definition and just need to get its HIR together with
-//! some information that is needed for futher steps of searching.
+//! some information that is needed for further steps of searching.
 //! After that, we collect files that might contain references and look
 //! for text occurrences of the identifier. If there's an `ast::NameRef`
 //! at the index that the match starts at and its tree parent is
@@ -21,7 +21,7 @@ use ide_db::{
 use syntax::{
     algo::find_node_at_offset,
     ast::{self, NameOwner},
-    match_ast, AstNode, SyntaxKind, SyntaxNode, TextRange, TokenAtOffset,
+    match_ast, AstNode, SyntaxNode, TextRange, TokenAtOffset, T,
 };
 
 use crate::{display::TryToNav, FilePosition, FileRange, NavigationTarget, RangeInfo, SymbolKind};
@@ -130,7 +130,10 @@ pub(crate) fn find_all_refs(
                 kind = ReferenceKind::FieldShorthandForLocal;
             }
         }
-    } else if matches!(def, Definition::LifetimeParam(_) | Definition::Label(_)) {
+    } else if matches!(
+        def,
+        Definition::GenericParam(hir::GenericParam::LifetimeParam(_)) | Definition::Label(_)
+    ) {
         kind = ReferenceKind::Lifetime;
     };
 
@@ -200,7 +203,7 @@ fn get_struct_def_name_for_struct_literal_search(
     position: FilePosition,
 ) -> Option<ast::Name> {
     if let TokenAtOffset::Between(ref left, ref right) = syntax.token_at_offset(position.offset) {
-        if right.kind() != SyntaxKind::L_CURLY && right.kind() != SyntaxKind::L_PAREN {
+        if right.kind() != T!['{'] && right.kind() != T!['('] {
             return None;
         }
         if let Some(name) =
@@ -227,7 +230,7 @@ fn get_enum_def_name_for_struct_literal_search(
     position: FilePosition,
 ) -> Option<ast::Name> {
     if let TokenAtOffset::Between(ref left, ref right) = syntax.token_at_offset(position.offset) {
-        if right.kind() != SyntaxKind::L_CURLY && right.kind() != SyntaxKind::L_PAREN {
+        if right.kind() != T!['{'] && right.kind() != T!['('] {
             return None;
         }
         if let Some(name) =
@@ -252,8 +255,7 @@ fn try_find_self_references(
     syntax: &SyntaxNode,
     position: FilePosition,
 ) -> Option<RangeInfo<ReferenceSearchResult>> {
-    let self_token =
-        syntax.token_at_offset(position.offset).find(|t| t.kind() == SyntaxKind::SELF_KW)?;
+    let self_token = syntax.token_at_offset(position.offset).find(|t| t.kind() == T![self])?;
     let parent = self_token.parent();
     match_ast! {
         match parent {
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/references/rename.rs
index 53d79333c..3edc43e08 100644
--- a/crates/ide/src/references/rename.rs
+++ b/crates/ide/src/references/rename.rs
@@ -14,16 +14,17 @@ use ide_db::{
 use syntax::{
     algo::find_node_at_offset,
     ast::{self, NameOwner},
-    lex_single_syntax_kind, match_ast, AstNode, SyntaxKind, SyntaxNode, SyntaxToken,
+    lex_single_syntax_kind, match_ast, AstNode, SyntaxKind, SyntaxNode, SyntaxToken, T,
 };
 use test_utils::mark;
 use text_edit::TextEdit;
 
 use crate::{
-    references::find_all_refs, FilePosition, FileSystemEdit, RangeInfo, Reference, ReferenceKind,
+    FilePosition, FileSystemEdit, RangeInfo, Reference, ReferenceKind, ReferenceSearchResult,
     SourceChange, SourceFileEdit, TextRange, TextSize,
 };
 
+type RenameResult<T> = Result<T, RenameError>;
 #[derive(Debug)]
 pub struct RenameError(pub(crate) String);
 
@@ -35,24 +36,30 @@ impl fmt::Display for RenameError {
 
 impl Error for RenameError {}
 
+macro_rules! format_err {
+    ($fmt:expr) => {RenameError(format!($fmt))};
+    ($fmt:expr, $($arg:tt)+) => {RenameError(format!($fmt, $($arg)+))}
+}
+
+macro_rules! bail {
+    ($($tokens:tt)*) => {return Err(format_err!($($tokens)*))}
+}
+
 pub(crate) fn prepare_rename(
     db: &RootDatabase,
     position: FilePosition,
-) -> Result<RangeInfo<()>, RenameError> {
+) -> RenameResult<RangeInfo<()>> {
     let sema = Semantics::new(db);
     let source_file = sema.parse(position.file_id);
     let syntax = source_file.syntax();
     if let Some(module) = find_module_at_offset(&sema, position, syntax) {
         rename_mod(&sema, position, module, "dummy")
     } else if let Some(self_token) =
-        syntax.token_at_offset(position.offset).find(|t| t.kind() == SyntaxKind::SELF_KW)
+        syntax.token_at_offset(position.offset).find(|t| t.kind() == T![self])
     {
         rename_self_to_param(&sema, position, self_token, "dummy")
     } else {
-        let range = match find_all_refs(&sema, position, None) {
-            Some(RangeInfo { range, .. }) => range,
-            None => return Err(RenameError("No references found at position".to_string())),
-        };
+        let RangeInfo { range, .. } = find_all_refs(&sema, position)?;
         Ok(RangeInfo::new(range, SourceChange::from(vec![])))
     }
     .map(|info| RangeInfo::new(info.range, ()))
@@ -62,7 +69,7 @@ pub(crate) fn rename(
     db: &RootDatabase,
     position: FilePosition,
     new_name: &str,
-) -> Result<RangeInfo<SourceChange>, RenameError> {
+) -> RenameResult<RangeInfo<SourceChange>> {
     let sema = Semantics::new(db);
     rename_with_semantics(&sema, position, new_name)
 }
@@ -71,42 +78,18 @@ pub(crate) fn rename_with_semantics(
     sema: &Semantics<RootDatabase>,
     position: FilePosition,
     new_name: &str,
-) -> Result<RangeInfo<SourceChange>, RenameError> {
-    let is_lifetime_name = match lex_single_syntax_kind(new_name) {
-        Some(res) => match res {
-            (SyntaxKind::IDENT, _) => false,
-            (SyntaxKind::UNDERSCORE, _) => false,
-            (SyntaxKind::SELF_KW, _) => return rename_to_self(&sema, position),
-            (SyntaxKind::LIFETIME_IDENT, _) if new_name != "'static" && new_name != "'_" => true,
-            (SyntaxKind::LIFETIME_IDENT, _) => {
-                return Err(RenameError(format!(
-                    "Invalid name `{0}`: Cannot rename lifetime to {0}",
-                    new_name
-                )))
-            }
-            (_, Some(syntax_error)) => {
-                return Err(RenameError(format!("Invalid name `{}`: {}", new_name, syntax_error)))
-            }
-            (_, None) => {
-                return Err(RenameError(format!("Invalid name `{}`: not an identifier", new_name)))
-            }
-        },
-        None => return Err(RenameError(format!("Invalid name `{}`: not an identifier", new_name))),
-    };
-
+) -> RenameResult<RangeInfo<SourceChange>> {
     let source_file = sema.parse(position.file_id);
     let syntax = source_file.syntax();
-    // this is here to prevent lifetime renames from happening on modules and self
-    if is_lifetime_name {
-        rename_reference(&sema, position, new_name, is_lifetime_name)
-    } else if let Some(module) = find_module_at_offset(&sema, position, syntax) {
+
+    if let Some(module) = find_module_at_offset(&sema, position, syntax) {
         rename_mod(&sema, position, module, new_name)
     } else if let Some(self_token) =
-        syntax.token_at_offset(position.offset).find(|t| t.kind() == SyntaxKind::SELF_KW)
+        syntax.token_at_offset(position.offset).find(|t| t.kind() == T![self])
     {
         rename_self_to_param(&sema, position, self_token, new_name)
     } else {
-        rename_reference(&sema, position, new_name, is_lifetime_name)
+        rename_reference(&sema, position, new_name)
     }
 }
 
@@ -127,6 +110,33 @@ pub(crate) fn will_rename_file(
     Some(change)
 }
 
+#[derive(Debug, PartialEq)]
+enum IdentifierKind {
+    Ident,
+    Lifetime,
+    ToSelf,
+    Underscore,
+}
+
+fn check_identifier(new_name: &str) -> RenameResult<IdentifierKind> {
+    match lex_single_syntax_kind(new_name) {
+        Some(res) => match res {
+            (SyntaxKind::IDENT, _) => Ok(IdentifierKind::Ident),
+            (T![_], _) => Ok(IdentifierKind::Underscore),
+            (T![self], _) => Ok(IdentifierKind::ToSelf),
+            (SyntaxKind::LIFETIME_IDENT, _) if new_name != "'static" && new_name != "'_" => {
+                Ok(IdentifierKind::Lifetime)
+            }
+            (SyntaxKind::LIFETIME_IDENT, _) => {
+                bail!("Invalid name `{0}`: Cannot rename lifetime to {0}", new_name)
+            }
+            (_, Some(syntax_error)) => bail!("Invalid name `{}`: {}", new_name, syntax_error),
+            (_, None) => bail!("Invalid name `{}`: not an identifier", new_name),
+        },
+        None => bail!("Invalid name `{}`: not an identifier", new_name),
+    }
+}
+
 fn find_module_at_offset(
     sema: &Semantics<RootDatabase>,
     position: FilePosition,
@@ -155,6 +165,14 @@ fn find_module_at_offset(
     Some(module)
 }
 
+fn find_all_refs(
+    sema: &Semantics<RootDatabase>,
+    position: FilePosition,
+) -> RenameResult<RangeInfo<ReferenceSearchResult>> {
+    crate::references::find_all_refs(sema, position, None)
+        .ok_or_else(|| format_err!("No references found at position"))
+}
+
 fn source_edit_from_reference(
     sema: &Semantics<RootDatabase>,
     reference: Reference,
@@ -223,7 +241,10 @@ fn rename_mod(
     position: FilePosition,
     module: Module,
     new_name: &str,
-) -> Result<RangeInfo<SourceChange>, RenameError> {
+) -> RenameResult<RangeInfo<SourceChange>> {
+    if IdentifierKind::Ident != check_identifier(new_name)? {
+        bail!("Invalid name `{0}`: cannot rename module to {0}", new_name);
+    }
     let mut source_file_edits = Vec::new();
     let mut file_system_edits = Vec::new();
 
@@ -254,8 +275,7 @@ fn rename_mod(
         source_file_edits.push(edit);
     }
 
-    let RangeInfo { range, info: refs } = find_all_refs(sema, position, None)
-        .ok_or_else(|| RenameError("No references found at position".to_string()))?;
+    let RangeInfo { range, info: refs } = find_all_refs(sema, position)?;
     let ref_edits = refs
         .references
         .into_iter()
@@ -274,27 +294,26 @@ fn rename_to_self(
 
     let (fn_def, fn_ast) = find_node_at_offset::<ast::Fn>(syn, position.offset)
         .and_then(|fn_ast| sema.to_def(&fn_ast).zip(Some(fn_ast)))
-        .ok_or_else(|| RenameError("No surrounding method declaration found".to_string()))?;
+        .ok_or_else(|| format_err!("No surrounding method declaration found"))?;
     let param_range = fn_ast
         .param_list()
         .and_then(|p| p.params().next())
-        .ok_or_else(|| RenameError("Method has no parameters".to_string()))?
+        .ok_or_else(|| format_err!("Method has no parameters"))?
         .syntax()
         .text_range();
     if !param_range.contains(position.offset) {
-        return Err(RenameError("Only the first parameter can be self".to_string()));
+        bail!("Only the first parameter can be self");
     }
 
     let impl_block = find_node_at_offset::<ast::Impl>(syn, position.offset)
         .and_then(|def| sema.to_def(&def))
-        .ok_or_else(|| RenameError("No impl block found for function".to_string()))?;
+        .ok_or_else(|| format_err!("No impl block found for function"))?;
     if fn_def.self_param(sema.db).is_some() {
-        return Err(RenameError("Method already has a self parameter".to_string()));
+        bail!("Method already has a self parameter");
     }
 
     let params = fn_def.assoc_fn_params(sema.db);
-    let first_param =
-        params.first().ok_or_else(|| RenameError("Method has no parameters".into()))?;
+    let first_param = params.first().ok_or_else(|| format_err!("Method has no parameters"))?;
     let first_param_ty = first_param.ty();
     let impl_ty = impl_block.target_ty(sema.db);
     let (ty, self_param) = if impl_ty.remove_ref().is_some() {
@@ -307,18 +326,17 @@ fn rename_to_self(
     };
 
     if ty != impl_ty {
-        return Err(RenameError("Parameter type differs from impl block type".to_string()));
+        bail!("Parameter type differs from impl block type");
     }
 
-    let RangeInfo { range, info: refs } = find_all_refs(sema, position, None)
-        .ok_or_else(|| RenameError("No reference found at position".to_string()))?;
+    let RangeInfo { range, info: refs } = find_all_refs(sema, position)?;
 
     let (param_ref, usages): (Vec<Reference>, Vec<Reference>) = refs
         .into_iter()
         .partition(|reference| param_range.intersect(reference.file_range.range).is_some());
 
     if param_ref.is_empty() {
-        return Err(RenameError("Parameter to rename not found".to_string()));
+        bail!("Parameter to rename not found");
     }
 
     let mut edits = usages
@@ -367,12 +385,22 @@ fn rename_self_to_param(
     self_token: SyntaxToken,
     new_name: &str,
 ) -> Result<RangeInfo<SourceChange>, RenameError> {
+    let ident_kind = check_identifier(new_name)?;
+    match ident_kind {
+        IdentifierKind::Lifetime => bail!("Invalid name `{}`: not an identifier", new_name),
+        IdentifierKind::ToSelf => {
+            // no-op
+            mark::hit!(rename_self_to_self);
+            return Ok(RangeInfo::new(self_token.text_range(), SourceChange::default()));
+        }
+        _ => (),
+    }
     let source_file = sema.parse(position.file_id);
     let syn = source_file.syntax();
 
     let text = sema.db.file_text(position.file_id);
     let fn_def = find_node_at_offset::<ast::Fn>(syn, position.offset)
-        .ok_or_else(|| RenameError("No surrounding method declaration found".to_string()))?;
+        .ok_or_else(|| format_err!("No surrounding method declaration found"))?;
     let search_range = fn_def.syntax().text_range();
 
     let mut edits: Vec<SourceFileEdit> = vec![];
@@ -382,12 +410,10 @@ fn rename_self_to_param(
         if !search_range.contains_inclusive(offset) {
             continue;
         }
-        if let Some(ref usage) =
-            syn.token_at_offset(offset).find(|t| t.kind() == SyntaxKind::SELF_KW)
-        {
+        if let Some(ref usage) = syn.token_at_offset(offset).find(|t| t.kind() == T![self]) {
             let edit = if let Some(ref self_param) = ast::SelfParam::cast(usage.parent()) {
                 text_edit_from_self_param(syn, self_param, new_name)
-                    .ok_or_else(|| RenameError("No target type found".to_string()))?
+                    .ok_or_else(|| format_err!("No target type found"))?
             } else {
                 TextEdit::replace(usage.text_range(), String::from(new_name))
             };
@@ -395,6 +421,10 @@ fn rename_self_to_param(
         }
     }
 
+    if edits.len() > 1 && ident_kind == IdentifierKind::Underscore {
+        bail!("Cannot rename reference to `_` as it is being referenced multiple times");
+    }
+
     let range = ast::SelfParam::cast(self_token.parent())
         .map_or(self_token.text_range(), |p| p.syntax().text_range());
 
@@ -405,24 +435,34 @@ fn rename_reference(
     sema: &Semantics<RootDatabase>,
     position: FilePosition,
     new_name: &str,
-    is_lifetime_name: bool,
 ) -> Result<RangeInfo<SourceChange>, RenameError> {
-    let RangeInfo { range, info: refs } = match find_all_refs(sema, position, None) {
-        Some(range_info) => range_info,
-        None => return Err(RenameError("No references found at position".to_string())),
-    };
-
-    match (refs.declaration.kind == ReferenceKind::Lifetime, is_lifetime_name) {
-        (true, false) => {
-            return Err(RenameError(format!(
-                "Invalid name `{}`: not a lifetime identifier",
-                new_name
-            )))
+    let ident_kind = check_identifier(new_name)?;
+    let RangeInfo { range, info: refs } = find_all_refs(sema, position)?;
+
+    match (ident_kind, &refs.declaration.kind) {
+        (IdentifierKind::ToSelf, ReferenceKind::Lifetime)
+        | (IdentifierKind::Underscore, ReferenceKind::Lifetime)
+        | (IdentifierKind::Ident, ReferenceKind::Lifetime) => {
+            mark::hit!(rename_not_a_lifetime_ident_ref);
+            bail!("Invalid name `{}`: not a lifetime identifier", new_name)
         }
-        (false, true) => {
-            return Err(RenameError(format!("Invalid name `{}`: not an identifier", new_name)))
+        (IdentifierKind::Lifetime, ReferenceKind::Lifetime) => mark::hit!(rename_lifetime),
+        (IdentifierKind::Lifetime, _) => {
+            mark::hit!(rename_not_an_ident_ref);
+            bail!("Invalid name `{}`: not an identifier", new_name)
         }
-        _ => (),
+        (IdentifierKind::ToSelf, ReferenceKind::SelfKw) => {
+            unreachable!("rename_self_to_param should've been called instead")
+        }
+        (IdentifierKind::ToSelf, _) => {
+            mark::hit!(rename_to_self);
+            return rename_to_self(sema, position);
+        }
+        (IdentifierKind::Underscore, _) if !refs.references.is_empty() => {
+            mark::hit!(rename_underscore_multiple);
+            bail!("Cannot rename reference to `_` as it is being referenced multiple times")
+        }
+        (IdentifierKind::Ident, _) | (IdentifierKind::Underscore, _) => mark::hit!(rename_ident),
     }
 
     let edit = refs
@@ -430,10 +470,6 @@ fn rename_reference(
         .map(|reference| source_edit_from_reference(sema, reference, new_name))
         .collect::<Vec<_>>();
 
-    if edit.is_empty() {
-        return Err(RenameError("No references found at position".to_string()));
-    }
-
     Ok(RangeInfo::new(range, SourceChange::from(edit)))
 }
 
@@ -462,9 +498,11 @@ mod tests {
                         text_edit_builder.replace(indel.delete, indel.insert);
                     }
                 }
-                let mut result = analysis.file_text(file_id.unwrap()).unwrap().to_string();
-                text_edit_builder.finish().apply(&mut result);
-                assert_eq_text!(ra_fixture_after, &*result);
+                if let Some(file_id) = file_id {
+                    let mut result = analysis.file_text(file_id).unwrap().to_string();
+                    text_edit_builder.finish().apply(&mut result);
+                    assert_eq_text!(ra_fixture_after, &*result);
+                }
             }
             Err(err) => {
                 if ra_fixture_after.starts_with("error:") {
@@ -530,6 +568,7 @@ mod tests {
 
     #[test]
     fn test_rename_to_invalid_identifier_lifetime() {
+        mark::check!(rename_not_an_ident_ref);
         check(
             "'foo",
             r#"fn main() { let i$0 = 1; }"#,
@@ -539,6 +578,7 @@ mod tests {
 
     #[test]
     fn test_rename_to_invalid_identifier_lifetime2() {
+        mark::check!(rename_not_a_lifetime_ident_ref);
         check(
             "foo",
             r#"fn main<'a>(_: &'a$0 ()) {}"#,
@@ -547,7 +587,27 @@ mod tests {
     }
 
     #[test]
+    fn test_rename_to_underscore_invalid() {
+        mark::check!(rename_underscore_multiple);
+        check(
+            "_",
+            r#"fn main(foo$0: ()) {foo;}"#,
+            "error: Cannot rename reference to `_` as it is being referenced multiple times",
+        );
+    }
+
+    #[test]
+    fn test_rename_mod_invalid() {
+        check(
+            "'foo",
+            r#"mod foo$0 {}"#,
+            "error: Invalid name `'foo`: cannot rename module to 'foo",
+        );
+    }
+
+    #[test]
     fn test_rename_for_local() {
+        mark::check!(rename_ident);
         check(
             "k",
             r#"
@@ -945,7 +1005,7 @@ use crate::foo$0::FooContent;
 //- /lib.rs
 mod fo$0o;
 //- /foo/mod.rs
-// emtpy
+// empty
 "#,
             expect![[r#"
                 RangeInfo {
@@ -995,7 +1055,7 @@ mod fo$0o;
 mod outer { mod fo$0o; }
 
 //- /outer/foo.rs
-// emtpy
+// empty
 "#,
             expect![[r#"
                 RangeInfo {
@@ -1178,6 +1238,7 @@ fn foo(f: foo::Foo) {
 
     #[test]
     fn test_parameter_to_self() {
+        mark::check!(rename_to_self);
         check(
             "self",
             r#"
@@ -1481,6 +1542,7 @@ fn foo(Foo { i: bar }: foo) -> i32 {
 
     #[test]
     fn test_rename_lifetimes() {
+        mark::check!(rename_lifetime);
         check(
             "'yeeee",
             r#"
@@ -1565,4 +1627,24 @@ fn foo<'a>() -> &'a () {
 "#,
         )
     }
+
+    #[test]
+    fn test_self_to_self() {
+        mark::check!(rename_self_to_self);
+        check(
+            "self",
+            r#"
+struct Foo;
+impl Foo {
+    fn foo(self$0) {}
+}
+"#,
+            r#"
+struct Foo;
+impl Foo {
+    fn foo(self) {}
+}
+"#,
+        )
+    }
 }
diff --git a/crates/ide/src/runnables.rs b/crates/ide/src/runnables.rs
index 557563d7e..f5ee7de86 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -3,7 +3,7 @@ use std::fmt;
 use assists::utils::test_related_attribute;
 use cfg::CfgExpr;
 use hir::{AsAssocItem, HasAttrs, HasSource, Semantics};
-use ide_db::RootDatabase;
+use ide_db::{defs::Definition, RootDatabase};
 use itertools::Itertools;
 use syntax::{
     ast::{self, AstNode, AttrsOwner, ModuleItemOwner},
@@ -96,21 +96,26 @@ impl Runnable {
 pub(crate) fn runnables(db: &RootDatabase, file_id: FileId) -> Vec<Runnable> {
     let sema = Semantics::new(db);
     let source_file = sema.parse(file_id);
-    source_file.syntax().descendants().filter_map(|i| runnable(&sema, i)).collect()
-}
-
-pub(crate) fn runnable(sema: &Semantics<RootDatabase>, item: SyntaxNode) -> Option<Runnable> {
-    let runnable_item = match_ast! {
-        match (item.clone()) {
-            ast::Fn(func) => {
-                let def = sema.to_def(&func)?;
-                runnable_fn(sema, def)
-            },
-            ast::Module(it) => runnable_mod(sema, it),
-            _ => None,
-        }
-    };
-    runnable_item.or_else(|| runnable_doctest(sema, item))
+    source_file
+        .syntax()
+        .descendants()
+        .filter_map(|item| {
+            let runnable = match_ast! {
+                match item {
+                    ast::Fn(func) => {
+                        let def = sema.to_def(&func)?;
+                        runnable_fn(&sema, def)
+                    },
+                    ast::Module(it) => runnable_mod(&sema, it),
+                    _ => None,
+                }
+            };
+            runnable.or_else(|| match doc_owner_to_def(&sema, item)? {
+                Definition::ModuleDef(def) => module_def_doctest(&sema, def),
+                _ => None,
+            })
+        })
+        .collect()
 }
 
 pub(crate) fn runnable_fn(sema: &Semantics<RootDatabase>, def: hir::Function) -> Option<Runnable> {
@@ -145,20 +150,49 @@ pub(crate) fn runnable_fn(sema: &Semantics<RootDatabase>, def: hir::Function) ->
     Some(Runnable { nav, kind, cfg })
 }
 
-fn runnable_doctest(sema: &Semantics<RootDatabase>, item: SyntaxNode) -> Option<Runnable> {
-    match_ast! {
+pub(crate) fn runnable_mod(
+    sema: &Semantics<RootDatabase>,
+    module: ast::Module,
+) -> Option<Runnable> {
+    if !has_test_function_or_multiple_test_submodules(&module) {
+        return None;
+    }
+    let module_def = sema.to_def(&module)?;
+
+    let path = module_def
+        .path_to_root(sema.db)
+        .into_iter()
+        .rev()
+        .filter_map(|it| it.name(sema.db))
+        .join("::");
+
+    let def = sema.to_def(&module)?;
+    let attrs = def.attrs(sema.db);
+    let cfg = attrs.cfg();
+    let nav = module_def.to_nav(sema.db);
+    Some(Runnable { nav, kind: RunnableKind::TestMod { path }, cfg })
+}
+
+// FIXME: figure out a proper API here.
+pub(crate) fn doc_owner_to_def(
+    sema: &Semantics<RootDatabase>,
+    item: SyntaxNode,
+) -> Option<Definition> {
+    let res: hir::ModuleDef = match_ast! {
         match item {
-            ast::Fn(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::Struct(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::Enum(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::Union(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::Trait(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::Const(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::Static(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            ast::TypeAlias(it) => module_def_doctest(sema, sema.to_def(&it)?.into()),
-            _ => None,
+            ast::SourceFile(it) => sema.scope(&item).module()?.into(),
+            ast::Fn(it) => sema.to_def(&it)?.into(),
+            ast::Struct(it) => sema.to_def(&it)?.into(),
+            ast::Enum(it) => sema.to_def(&it)?.into(),
+            ast::Union(it) => sema.to_def(&it)?.into(),
+            ast::Trait(it) => sema.to_def(&it)?.into(),
+            ast::Const(it) => sema.to_def(&it)?.into(),
+            ast::Static(it) => sema.to_def(&it)?.into(),
+            ast::TypeAlias(it) => sema.to_def(&it)?.into(),
+            _ => return None,
         }
-    }
+    };
+    Some(Definition::ModuleDef(res))
 }
 
 fn module_def_doctest(sema: &Semantics<RootDatabase>, def: hir::ModuleDef) -> Option<Runnable> {
@@ -253,26 +287,6 @@ fn has_runnable_doc_test(attrs: &hir::Attrs) -> bool {
     })
 }
 
-fn runnable_mod(sema: &Semantics<RootDatabase>, module: ast::Module) -> Option<Runnable> {
-    if !has_test_function_or_multiple_test_submodules(&module) {
-        return None;
-    }
-    let module_def = sema.to_def(&module)?;
-
-    let path = module_def
-        .path_to_root(sema.db)
-        .into_iter()
-        .rev()
-        .filter_map(|it| it.name(sema.db))
-        .join("::");
-
-    let def = sema.to_def(&module)?;
-    let attrs = def.attrs(sema.db);
-    let cfg = attrs.cfg();
-    let nav = module_def.to_nav(sema.db);
-    Some(Runnable { nav, kind: RunnableKind::TestMod { path }, cfg })
-}
-
 // We could create runnables for modules with number_of_test_submodules > 0,
 // but that bloats the runnables for no real benefit, since all tests can be run by the submodule already
 fn has_test_function_or_multiple_test_submodules(module: &ast::Module) -> bool {
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index ba0085244..f2d4da78d 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -1,35 +1,39 @@
+pub(crate) mod tags;
+
+mod highlights;
+mod injector;
+
+mod highlight;
 mod format;
-mod html;
-mod injection;
 mod macro_rules;
-pub(crate) mod tags;
+mod inject;
+
+mod html;
 #[cfg(test)]
 mod tests;
 
-use hir::{AsAssocItem, Local, Name, Semantics, VariantDef};
-use ide_db::{
-    defs::{Definition, NameClass, NameRefClass},
-    RootDatabase,
-};
+use hir::{Name, Semantics};
+use ide_db::RootDatabase;
 use rustc_hash::FxHashMap;
 use syntax::{
     ast::{self, HasFormatSpecifier},
-    AstNode, AstToken, Direction, NodeOrToken, SyntaxElement,
-    SyntaxKind::{self, *},
-    SyntaxNode, SyntaxToken, TextRange, WalkEvent, T,
+    AstNode, AstToken, Direction, NodeOrToken,
+    SyntaxKind::*,
+    SyntaxNode, TextRange, WalkEvent, T,
 };
 
 use crate::{
     syntax_highlighting::{
-        format::FormatStringHighlighter, macro_rules::MacroRulesHighlighter, tags::Highlight,
+        format::highlight_format_string, highlights::Highlights,
+        macro_rules::MacroRulesHighlighter, tags::Highlight,
     },
-    FileId, HighlightModifier, HighlightTag, SymbolKind,
+    FileId, HlMod, HlTag, SymbolKind,
 };
 
 pub(crate) use html::highlight_as_html;
 
-#[derive(Debug, Clone)]
-pub struct HighlightedRange {
+#[derive(Debug, Clone, Copy)]
+pub struct HlRange {
     pub range: TextRange,
     pub highlight: Highlight,
     pub binding_hash: Option<u64>,
@@ -49,7 +53,7 @@ pub(crate) fn highlight(
     file_id: FileId,
     range_to_highlight: Option<TextRange>,
     syntactic_name_ref_highlighting: bool,
-) -> Vec<HighlightedRange> {
+) -> Vec<HlRange> {
     let _p = profile::span("highlight");
     let sema = Semantics::new(db);
 
@@ -68,28 +72,30 @@ pub(crate) fn highlight(
         }
     };
 
+    let mut hl = highlights::Highlights::new(range_to_highlight);
+    traverse(&mut hl, &sema, &root, range_to_highlight, syntactic_name_ref_highlighting);
+    hl.to_vec()
+}
+
+fn traverse(
+    hl: &mut Highlights,
+    sema: &Semantics<RootDatabase>,
+    root: &SyntaxNode,
+    range_to_highlight: TextRange,
+    syntactic_name_ref_highlighting: bool,
+) {
     let mut bindings_shadow_count: FxHashMap<Name, u32> = FxHashMap::default();
-    // We use a stack for the DFS traversal below.
-    // When we leave a node, the we use it to flatten the highlighted ranges.
-    let mut stack = HighlightedRangeStack::new();
 
     let mut current_macro_call: Option<ast::MacroCall> = None;
     let mut current_macro_rules: Option<ast::MacroRules> = None;
-    let mut format_string_highlighter = FormatStringHighlighter::default();
     let mut macro_rules_highlighter = MacroRulesHighlighter::default();
     let mut inside_attribute = false;
 
     // Walk all nodes, keeping track of whether we are inside a macro or not.
     // If in macro, expand it first and highlight the expanded code.
     for event in root.preorder_with_tokens() {
-        match &event {
-            WalkEvent::Enter(_) => stack.push(),
-            WalkEvent::Leave(_) => stack.pop(),
-        };
-
         let event_range = match &event {
-            WalkEvent::Enter(it) => it.text_range(),
-            WalkEvent::Leave(it) => it.text_range(),
+            WalkEvent::Enter(it) | WalkEvent::Leave(it) => it.text_range(),
         };
 
         // Element outside of the viewport, no need to highlight
@@ -101,9 +107,9 @@ pub(crate) fn highlight(
         match event.clone().map(|it| it.into_node().and_then(ast::MacroCall::cast)) {
             WalkEvent::Enter(Some(mc)) => {
                 if let Some(range) = macro_call_range(&mc) {
-                    stack.add(HighlightedRange {
+                    hl.add(HlRange {
                         range,
-                        highlight: HighlightTag::Symbol(SymbolKind::Macro).into(),
+                        highlight: HlTag::Symbol(SymbolKind::Macro).into(),
                         binding_hash: None,
                     });
                 }
@@ -113,7 +119,6 @@ pub(crate) fn highlight(
             WalkEvent::Leave(Some(mc)) => {
                 assert_eq!(current_macro_call, Some(mc));
                 current_macro_call = None;
-                format_string_highlighter = FormatStringHighlighter::default();
             }
             _ => (),
         }
@@ -131,33 +136,24 @@ pub(crate) fn highlight(
             }
             _ => (),
         }
-
         match &event {
-            // Check for Rust code in documentation
-            WalkEvent::Leave(NodeOrToken::Node(node)) => {
-                if ast::Attr::can_cast(node.kind()) {
-                    inside_attribute = false
-                }
-                if let Some((doctest, range_mapping, new_comments)) =
-                    injection::extract_doc_comments(node)
-                {
-                    injection::highlight_doc_comment(
-                        doctest,
-                        range_mapping,
-                        new_comments,
-                        &mut stack,
-                    );
-                }
-            }
             WalkEvent::Enter(NodeOrToken::Node(node)) if ast::Attr::can_cast(node.kind()) => {
                 inside_attribute = true
             }
+            WalkEvent::Leave(NodeOrToken::Node(node)) if ast::Attr::can_cast(node.kind()) => {
+                inside_attribute = false
+            }
             _ => (),
         }
 
         let element = match event {
             WalkEvent::Enter(it) => it,
-            WalkEvent::Leave(_) => continue,
+            WalkEvent::Leave(it) => {
+                if let Some(node) = it.as_node() {
+                    inject::doc_comment(hl, node);
+                }
+                continue;
+            }
         };
 
         let range = element.text_range();
@@ -177,8 +173,6 @@ pub(crate) fn highlight(
             let token = sema.descend_into_macros(token.clone());
             let parent = token.parent();
 
-            format_string_highlighter.check_for_format_string(&parent);
-
             // We only care Name and Name_ref
             match (token.kind(), parent.kind()) {
                 (IDENT, NAME) | (IDENT, NAME_REF) => parent.into(),
@@ -191,213 +185,45 @@ pub(crate) fn highlight(
         if let Some(token) = element.as_token().cloned().and_then(ast::String::cast) {
             if token.is_raw() {
                 let expanded = element_to_highlight.as_token().unwrap().clone();
-                if injection::highlight_injection(&mut stack, &sema, token, expanded).is_some() {
+                if inject::ra_fixture(hl, &sema, token, expanded).is_some() {
                     continue;
                 }
             }
         }
 
-        if let Some((mut highlight, binding_hash)) = highlight_element(
+        if let Some(_) = macro_rules_highlighter.highlight(element_to_highlight.clone()) {
+            continue;
+        }
+
+        if let Some((mut highlight, binding_hash)) = highlight::element(
             &sema,
             &mut bindings_shadow_count,
             syntactic_name_ref_highlighting,
             element_to_highlight.clone(),
         ) {
             if inside_attribute {
-                highlight = highlight | HighlightModifier::Attribute;
-            }
-
-            if macro_rules_highlighter.highlight(element_to_highlight.clone()).is_none() {
-                stack.add(HighlightedRange { range, highlight, binding_hash });
+                highlight = highlight | HlMod::Attribute;
             }
 
-            if let Some(string) =
-                element_to_highlight.as_token().cloned().and_then(ast::String::cast)
-            {
-                format_string_highlighter.highlight_format_string(&mut stack, &string, range);
-                // Highlight escape sequences
-                if let Some(char_ranges) = string.char_ranges() {
-                    stack.push();
-                    for (piece_range, _) in char_ranges.iter().filter(|(_, char)| char.is_ok()) {
-                        if string.text()[piece_range.start().into()..].starts_with('\\') {
-                            stack.add(HighlightedRange {
-                                range: piece_range + range.start(),
-                                highlight: HighlightTag::EscapeSequence.into(),
-                                binding_hash: None,
-                            });
-                        }
-                    }
-                    stack.pop_and_inject(None);
-                }
-            }
+            hl.add(HlRange { range, highlight, binding_hash });
         }
-    }
-
-    stack.flattened()
-}
-
-#[derive(Debug)]
-struct HighlightedRangeStack {
-    stack: Vec<Vec<HighlightedRange>>,
-}
-
-/// We use a stack to implement the flattening logic for the highlighted
-/// syntax ranges.
-impl HighlightedRangeStack {
-    fn new() -> Self {
-        Self { stack: vec![Vec::new()] }
-    }
-
-    fn push(&mut self) {
-        self.stack.push(Vec::new());
-    }
-
-    /// Flattens the highlighted ranges.
-    ///
-    /// For example `#[cfg(feature = "foo")]` contains the nested ranges:
-    /// 1) parent-range: Attribute [0, 23)
-    /// 2) child-range: String [16, 21)
-    ///
-    /// The following code implements the flattening, for our example this results to:
-    /// `[Attribute [0, 16), String [16, 21), Attribute [21, 23)]`
-    fn pop(&mut self) {
-        let children = self.stack.pop().unwrap();
-        let prev = self.stack.last_mut().unwrap();
-        let needs_flattening = !children.is_empty()
-            && !prev.is_empty()
-            && prev.last().unwrap().range.contains_range(children.first().unwrap().range);
-        if !needs_flattening {
-            prev.extend(children);
-        } else {
-            let mut parent = prev.pop().unwrap();
-            for ele in children {
-                assert!(parent.range.contains_range(ele.range));
-
-                let cloned = Self::intersect(&mut parent, &ele);
-                if !parent.range.is_empty() {
-                    prev.push(parent);
-                }
-                prev.push(ele);
-                parent = cloned;
-            }
-            if !parent.range.is_empty() {
-                prev.push(parent);
-            }
-        }
-    }
-
-    /// Intersects the `HighlightedRange` `parent` with `child`.
-    /// `parent` is mutated in place, becoming the range before `child`.
-    /// Returns the range (of the same type as `parent`) *after* `child`.
-    fn intersect(parent: &mut HighlightedRange, child: &HighlightedRange) -> HighlightedRange {
-        assert!(parent.range.contains_range(child.range));
-
-        let mut cloned = parent.clone();
-        parent.range = TextRange::new(parent.range.start(), child.range.start());
-        cloned.range = TextRange::new(child.range.end(), cloned.range.end());
 
-        cloned
-    }
-
-    /// Remove the `HighlightRange` of `parent` that's currently covered by `child`.
-    fn intersect_partial(parent: &mut HighlightedRange, child: &HighlightedRange) {
-        assert!(
-            parent.range.start() <= child.range.start()
-                && parent.range.end() >= child.range.start()
-                && child.range.end() > parent.range.end()
-        );
-
-        parent.range = TextRange::new(parent.range.start(), child.range.start());
-    }
-
-    /// Similar to `pop`, but can modify arbitrary prior ranges (where `pop`)
-    /// can only modify the last range currently on the stack.
-    /// Can be used to do injections that span multiple ranges, like the
-    /// doctest injection below.
-    /// If `overwrite_parent` is non-optional, the highlighting of the parent range
-    /// is overwritten with the argument.
-    ///
-    /// Note that `pop` can be simulated by `pop_and_inject(false)` but the
-    /// latter is computationally more expensive.
-    fn pop_and_inject(&mut self, overwrite_parent: Option<Highlight>) {
-        let mut children = self.stack.pop().unwrap();
-        let prev = self.stack.last_mut().unwrap();
-        children.sort_by_key(|range| range.range.start());
-        prev.sort_by_key(|range| range.range.start());
-
-        for child in children {
-            if let Some(idx) =
-                prev.iter().position(|parent| parent.range.contains_range(child.range))
-            {
-                if let Some(tag) = overwrite_parent {
-                    prev[idx].highlight = tag;
-                }
-
-                let cloned = Self::intersect(&mut prev[idx], &child);
-                let insert_idx = if prev[idx].range.is_empty() {
-                    prev.remove(idx);
-                    idx
-                } else {
-                    idx + 1
-                };
-                prev.insert(insert_idx, child);
-                if !cloned.range.is_empty() {
-                    prev.insert(insert_idx + 1, cloned);
-                }
-            } else {
-                let maybe_idx =
-                    prev.iter().position(|parent| parent.range.contains(child.range.start()));
-                match (overwrite_parent, maybe_idx) {
-                    (Some(_), Some(idx)) => {
-                        Self::intersect_partial(&mut prev[idx], &child);
-                        let insert_idx = if prev[idx].range.is_empty() {
-                            prev.remove(idx);
-                            idx
-                        } else {
-                            idx + 1
-                        };
-                        prev.insert(insert_idx, child);
-                    }
-                    (_, None) => {
-                        let idx = prev
-                            .binary_search_by_key(&child.range.start(), |range| range.range.start())
-                            .unwrap_or_else(|x| x);
-                        prev.insert(idx, child);
-                    }
-                    _ => {
-                        unreachable!("child range should be completely contained in parent range");
+        if let Some(string) = element_to_highlight.as_token().cloned().and_then(ast::String::cast) {
+            highlight_format_string(hl, &string, range);
+            // Highlight escape sequences
+            if let Some(char_ranges) = string.char_ranges() {
+                for (piece_range, _) in char_ranges.iter().filter(|(_, char)| char.is_ok()) {
+                    if string.text()[piece_range.start().into()..].starts_with('\\') {
+                        hl.add(HlRange {
+                            range: piece_range + range.start(),
+                            highlight: HlTag::EscapeSequence.into(),
+                            binding_hash: None,
+                        });
                     }
                 }
             }
         }
     }
-
-    fn add(&mut self, range: HighlightedRange) {
-        self.stack
-            .last_mut()
-            .expect("during DFS traversal, the stack must not be empty")
-            .push(range)
-    }
-
-    fn flattened(mut self) -> Vec<HighlightedRange> {
-        assert_eq!(
-            self.stack.len(),
-            1,
-            "after DFS traversal, the stack should only contain a single element"
-        );
-        let mut res = self.stack.pop().unwrap();
-        res.sort_by_key(|range| range.range.start());
-        // Check that ranges are sorted and disjoint
-        for (left, right) in res.iter().zip(res.iter().skip(1)) {
-            assert!(
-                left.range.end() <= right.range.start(),
-                "left: {:#?}, right: {:#?}",
-                left,
-                right
-            );
-        }
-        res
-    }
 }
 
 fn macro_call_range(macro_call: &ast::MacroCall) -> Option<TextRange> {
@@ -415,524 +241,3 @@ fn macro_call_range(macro_call: &ast::MacroCall) -> Option<TextRange> {
 
     Some(TextRange::new(range_start, range_end))
 }
-
-/// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
-fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
-    while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
-        if parent.kind() != *kind {
-            return false;
-        }
-
-        // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
-        // in the same pattern is unstable: rust-lang/rust#68354.
-        node = node.parent().unwrap().into();
-        kinds = rest;
-    }
-
-    // Only true if we matched all expected kinds
-    kinds.len() == 0
-}
-
-fn is_consumed_lvalue(
-    node: NodeOrToken<SyntaxNode, SyntaxToken>,
-    local: &Local,
-    db: &RootDatabase,
-) -> bool {
-    // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
-    parents_match(node, &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST]) && !local.ty(db).is_copy(db)
-}
-
-fn highlight_element(
-    sema: &Semantics<RootDatabase>,
-    bindings_shadow_count: &mut FxHashMap<Name, u32>,
-    syntactic_name_ref_highlighting: bool,
-    element: SyntaxElement,
-) -> Option<(Highlight, Option<u64>)> {
-    let db = sema.db;
-    let mut binding_hash = None;
-    let highlight: Highlight = match element.kind() {
-        FN => {
-            bindings_shadow_count.clear();
-            return None;
-        }
-
-        // Highlight definitions depending on the "type" of the definition.
-        NAME => {
-            let name = element.into_node().and_then(ast::Name::cast).unwrap();
-            let name_kind = NameClass::classify(sema, &name);
-
-            if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
-                if let Some(name) = local.name(db) {
-                    let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
-                    *shadow_count += 1;
-                    binding_hash = Some(calc_binding_hash(&name, *shadow_count))
-                }
-            };
-
-            match name_kind {
-                Some(NameClass::ExternCrate(_)) => HighlightTag::Symbol(SymbolKind::Module).into(),
-                Some(NameClass::Definition(def)) => {
-                    highlight_def(db, def) | HighlightModifier::Definition
-                }
-                Some(NameClass::ConstReference(def)) => highlight_def(db, def),
-                Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
-                    let mut h = HighlightTag::Symbol(SymbolKind::Field).into();
-                    if let Definition::Field(field) = field_ref {
-                        if let VariantDef::Union(_) = field.parent_def(db) {
-                            h |= HighlightModifier::Unsafe;
-                        }
-                    }
-
-                    h
-                }
-                None => highlight_name_by_syntax(name) | HighlightModifier::Definition,
-            }
-        }
-
-        // Highlight references like the definitions they resolve to
-        NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
-            // even though we track whether we are in an attribute or not we still need this special case
-            // as otherwise we would emit unresolved references for name refs inside attributes
-            Highlight::from(HighlightTag::Symbol(SymbolKind::Function))
-        }
-        NAME_REF => {
-            let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
-            highlight_func_by_name_ref(sema, &name_ref).unwrap_or_else(|| {
-                match NameRefClass::classify(sema, &name_ref) {
-                    Some(name_kind) => match name_kind {
-                        NameRefClass::ExternCrate(_) => {
-                            HighlightTag::Symbol(SymbolKind::Module).into()
-                        }
-                        NameRefClass::Definition(def) => {
-                            if let Definition::Local(local) = &def {
-                                if let Some(name) = local.name(db) {
-                                    let shadow_count =
-                                        bindings_shadow_count.entry(name.clone()).or_default();
-                                    binding_hash = Some(calc_binding_hash(&name, *shadow_count))
-                                }
-                            };
-
-                            let mut h = highlight_def(db, def);
-
-                            if let Definition::Local(local) = &def {
-                                if is_consumed_lvalue(name_ref.syntax().clone().into(), local, db) {
-                                    h |= HighlightModifier::Consuming;
-                                }
-                            }
-
-                            if let Some(parent) = name_ref.syntax().parent() {
-                                if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
-                                    if let Definition::Field(field) = def {
-                                        if let VariantDef::Union(_) = field.parent_def(db) {
-                                            h |= HighlightModifier::Unsafe;
-                                        }
-                                    }
-                                }
-                            }
-
-                            h
-                        }
-                        NameRefClass::FieldShorthand { .. } => {
-                            HighlightTag::Symbol(SymbolKind::Field).into()
-                        }
-                    },
-                    None if syntactic_name_ref_highlighting => {
-                        highlight_name_ref_by_syntax(name_ref, sema)
-                    }
-                    None => HighlightTag::UnresolvedReference.into(),
-                }
-            })
-        }
-
-        // Simple token-based highlighting
-        COMMENT => {
-            let comment = element.into_token().and_then(ast::Comment::cast)?;
-            let h = HighlightTag::Comment;
-            match comment.kind().doc {
-                Some(_) => h | HighlightModifier::Documentation,
-                None => h.into(),
-            }
-        }
-        STRING | BYTE_STRING => HighlightTag::StringLiteral.into(),
-        ATTR => HighlightTag::Attribute.into(),
-        INT_NUMBER | FLOAT_NUMBER => HighlightTag::NumericLiteral.into(),
-        BYTE => HighlightTag::ByteLiteral.into(),
-        CHAR => HighlightTag::CharLiteral.into(),
-        QUESTION => Highlight::new(HighlightTag::Operator) | HighlightModifier::ControlFlow,
-        LIFETIME => {
-            let lifetime = element.into_node().and_then(ast::Lifetime::cast).unwrap();
-
-            match NameClass::classify_lifetime(sema, &lifetime) {
-                Some(NameClass::Definition(def)) => {
-                    highlight_def(db, def) | HighlightModifier::Definition
-                }
-                None => match NameRefClass::classify_lifetime(sema, &lifetime) {
-                    Some(NameRefClass::Definition(def)) => highlight_def(db, def),
-                    _ => Highlight::new(HighlightTag::Symbol(SymbolKind::LifetimeParam)),
-                },
-                _ => {
-                    Highlight::new(HighlightTag::Symbol(SymbolKind::LifetimeParam))
-                        | HighlightModifier::Definition
-                }
-            }
-        }
-        p if p.is_punct() => match p {
-            T![&] => {
-                let h = HighlightTag::Operator.into();
-                let is_unsafe = element
-                    .parent()
-                    .and_then(ast::RefExpr::cast)
-                    .map(|ref_expr| sema.is_unsafe_ref_expr(&ref_expr))
-                    .unwrap_or(false);
-                if is_unsafe {
-                    h | HighlightModifier::Unsafe
-                } else {
-                    h
-                }
-            }
-            T![::] | T![->] | T![=>] | T![..] | T![=] | T![@] | T![.] => {
-                HighlightTag::Operator.into()
-            }
-            T![!] if element.parent().and_then(ast::MacroCall::cast).is_some() => {
-                HighlightTag::Symbol(SymbolKind::Macro).into()
-            }
-            T![!] if element.parent().and_then(ast::NeverType::cast).is_some() => {
-                HighlightTag::BuiltinType.into()
-            }
-            T![*] if element.parent().and_then(ast::PtrType::cast).is_some() => {
-                HighlightTag::Keyword.into()
-            }
-            T![*] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
-                let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
-
-                let expr = prefix_expr.expr()?;
-                let ty = sema.type_of_expr(&expr)?;
-                if ty.is_raw_ptr() {
-                    HighlightTag::Operator | HighlightModifier::Unsafe
-                } else if let Some(ast::PrefixOp::Deref) = prefix_expr.op_kind() {
-                    HighlightTag::Operator.into()
-                } else {
-                    HighlightTag::Punctuation.into()
-                }
-            }
-            T![-] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
-                let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
-
-                let expr = prefix_expr.expr()?;
-                match expr {
-                    ast::Expr::Literal(_) => HighlightTag::NumericLiteral,
-                    _ => HighlightTag::Operator,
-                }
-                .into()
-            }
-            _ if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
-                HighlightTag::Operator.into()
-            }
-            _ if element.parent().and_then(ast::BinExpr::cast).is_some() => {
-                HighlightTag::Operator.into()
-            }
-            _ if element.parent().and_then(ast::RangeExpr::cast).is_some() => {
-                HighlightTag::Operator.into()
-            }
-            _ if element.parent().and_then(ast::RangePat::cast).is_some() => {
-                HighlightTag::Operator.into()
-            }
-            _ if element.parent().and_then(ast::RestPat::cast).is_some() => {
-                HighlightTag::Operator.into()
-            }
-            _ if element.parent().and_then(ast::Attr::cast).is_some() => {
-                HighlightTag::Attribute.into()
-            }
-            _ => HighlightTag::Punctuation.into(),
-        },
-
-        k if k.is_keyword() => {
-            let h = Highlight::new(HighlightTag::Keyword);
-            match k {
-                T![break]
-                | T![continue]
-                | T![else]
-                | T![if]
-                | T![loop]
-                | T![match]
-                | T![return]
-                | T![while]
-                | T![in] => h | HighlightModifier::ControlFlow,
-                T![for] if !is_child_of_impl(&element) => h | HighlightModifier::ControlFlow,
-                T![unsafe] => h | HighlightModifier::Unsafe,
-                T![true] | T![false] => HighlightTag::BoolLiteral.into(),
-                T![self] => {
-                    let self_param_is_mut = element
-                        .parent()
-                        .and_then(ast::SelfParam::cast)
-                        .and_then(|p| p.mut_token())
-                        .is_some();
-                    let self_path = &element
-                        .parent()
-                        .as_ref()
-                        .and_then(SyntaxNode::parent)
-                        .and_then(ast::Path::cast)
-                        .and_then(|p| sema.resolve_path(&p));
-                    let mut h = HighlightTag::Symbol(SymbolKind::SelfParam).into();
-                    if self_param_is_mut
-                        || matches!(self_path,
-                            Some(hir::PathResolution::Local(local))
-                                if local.is_self(db)
-                                    && (local.is_mut(db) || local.ty(db).is_mutable_reference())
-                        )
-                    {
-                        h |= HighlightModifier::Mutable
-                    }
-
-                    if let Some(hir::PathResolution::Local(local)) = self_path {
-                        if is_consumed_lvalue(element, &local, db) {
-                            h |= HighlightModifier::Consuming;
-                        }
-                    }
-
-                    h
-                }
-                T![ref] => element
-                    .parent()
-                    .and_then(ast::IdentPat::cast)
-                    .and_then(|ident_pat| {
-                        if sema.is_unsafe_ident_pat(&ident_pat) {
-                            Some(HighlightModifier::Unsafe)
-                        } else {
-                            None
-                        }
-                    })
-                    .map(|modifier| h | modifier)
-                    .unwrap_or(h),
-                _ => h,
-            }
-        }
-
-        _ => return None,
-    };
-
-    return Some((highlight, binding_hash));
-
-    fn calc_binding_hash(name: &Name, shadow_count: u32) -> u64 {
-        fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
-            use std::{collections::hash_map::DefaultHasher, hash::Hasher};
-
-            let mut hasher = DefaultHasher::new();
-            x.hash(&mut hasher);
-            hasher.finish()
-        }
-
-        hash((name, shadow_count))
-    }
-}
-
-fn is_child_of_impl(element: &SyntaxElement) -> bool {
-    match element.parent() {
-        Some(e) => e.kind() == IMPL,
-        _ => false,
-    }
-}
-
-fn highlight_func_by_name_ref(
-    sema: &Semantics<RootDatabase>,
-    name_ref: &ast::NameRef,
-) -> Option<Highlight> {
-    let method_call = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
-    highlight_method_call(sema, &method_call)
-}
-
-fn highlight_method_call(
-    sema: &Semantics<RootDatabase>,
-    method_call: &ast::MethodCallExpr,
-) -> Option<Highlight> {
-    let func = sema.resolve_method_call(&method_call)?;
-    let mut h = HighlightTag::Symbol(SymbolKind::Function).into();
-    h |= HighlightModifier::Associated;
-    if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(&method_call) {
-        h |= HighlightModifier::Unsafe;
-    }
-    if let Some(self_param) = func.self_param(sema.db) {
-        match self_param.access(sema.db) {
-            hir::Access::Shared => (),
-            hir::Access::Exclusive => h |= HighlightModifier::Mutable,
-            hir::Access::Owned => {
-                if let Some(receiver_ty) =
-                    method_call.receiver().and_then(|it| sema.type_of_expr(&it))
-                {
-                    if !receiver_ty.is_copy(sema.db) {
-                        h |= HighlightModifier::Consuming
-                    }
-                }
-            }
-        }
-    }
-    Some(h)
-}
-
-fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
-    match def {
-        Definition::Macro(_) => HighlightTag::Symbol(SymbolKind::Macro),
-        Definition::Field(_) => HighlightTag::Symbol(SymbolKind::Field),
-        Definition::ModuleDef(def) => match def {
-            hir::ModuleDef::Module(_) => HighlightTag::Symbol(SymbolKind::Module),
-            hir::ModuleDef::Function(func) => {
-                let mut h = Highlight::new(HighlightTag::Symbol(SymbolKind::Function));
-                if func.as_assoc_item(db).is_some() {
-                    h |= HighlightModifier::Associated;
-                    if func.self_param(db).is_none() {
-                        h |= HighlightModifier::Static
-                    }
-                }
-                if func.is_unsafe(db) {
-                    h |= HighlightModifier::Unsafe;
-                }
-                return h;
-            }
-            hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HighlightTag::Symbol(SymbolKind::Struct),
-            hir::ModuleDef::Adt(hir::Adt::Enum(_)) => HighlightTag::Symbol(SymbolKind::Enum),
-            hir::ModuleDef::Adt(hir::Adt::Union(_)) => HighlightTag::Symbol(SymbolKind::Union),
-            hir::ModuleDef::Variant(_) => HighlightTag::Symbol(SymbolKind::Variant),
-            hir::ModuleDef::Const(konst) => {
-                let mut h = Highlight::new(HighlightTag::Symbol(SymbolKind::Const));
-                if konst.as_assoc_item(db).is_some() {
-                    h |= HighlightModifier::Associated
-                }
-                return h;
-            }
-            hir::ModuleDef::Trait(_) => HighlightTag::Symbol(SymbolKind::Trait),
-            hir::ModuleDef::TypeAlias(type_) => {
-                let mut h = Highlight::new(HighlightTag::Symbol(SymbolKind::TypeAlias));
-                if type_.as_assoc_item(db).is_some() {
-                    h |= HighlightModifier::Associated
-                }
-                return h;
-            }
-            hir::ModuleDef::BuiltinType(_) => HighlightTag::BuiltinType,
-            hir::ModuleDef::Static(s) => {
-                let mut h = Highlight::new(HighlightTag::Symbol(SymbolKind::Static));
-                if s.is_mut(db) {
-                    h |= HighlightModifier::Mutable;
-                    h |= HighlightModifier::Unsafe;
-                }
-                return h;
-            }
-        },
-        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)
-            } else {
-                HighlightTag::Symbol(SymbolKind::Local)
-            };
-            let mut h = Highlight::new(tag);
-            if local.is_mut(db) || local.ty(db).is_mutable_reference() {
-                h |= HighlightModifier::Mutable;
-            }
-            if local.ty(db).as_callable(db).is_some() || local.ty(db).impls_fnonce(db) {
-                h |= HighlightModifier::Callable;
-            }
-            return h;
-        }
-        Definition::LifetimeParam(_) => HighlightTag::Symbol(SymbolKind::LifetimeParam),
-        Definition::Label(_) => HighlightTag::Symbol(SymbolKind::Label),
-    }
-    .into()
-}
-
-fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
-    let default = HighlightTag::UnresolvedReference;
-
-    let parent = match name.syntax().parent() {
-        Some(it) => it,
-        _ => return default.into(),
-    };
-
-    let tag = match parent.kind() {
-        STRUCT => HighlightTag::Symbol(SymbolKind::Struct),
-        ENUM => HighlightTag::Symbol(SymbolKind::Enum),
-        VARIANT => HighlightTag::Symbol(SymbolKind::Variant),
-        UNION => HighlightTag::Symbol(SymbolKind::Union),
-        TRAIT => HighlightTag::Symbol(SymbolKind::Trait),
-        TYPE_ALIAS => HighlightTag::Symbol(SymbolKind::TypeAlias),
-        TYPE_PARAM => HighlightTag::Symbol(SymbolKind::TypeParam),
-        RECORD_FIELD => HighlightTag::Symbol(SymbolKind::Field),
-        MODULE => HighlightTag::Symbol(SymbolKind::Module),
-        FN => HighlightTag::Symbol(SymbolKind::Function),
-        CONST => HighlightTag::Symbol(SymbolKind::Const),
-        STATIC => HighlightTag::Symbol(SymbolKind::Static),
-        IDENT_PAT => HighlightTag::Symbol(SymbolKind::Local),
-        _ => default,
-    };
-
-    tag.into()
-}
-
-fn highlight_name_ref_by_syntax(name: ast::NameRef, sema: &Semantics<RootDatabase>) -> Highlight {
-    let default = HighlightTag::UnresolvedReference;
-
-    let parent = match name.syntax().parent() {
-        Some(it) => it,
-        _ => return default.into(),
-    };
-
-    match parent.kind() {
-        METHOD_CALL_EXPR => {
-            return ast::MethodCallExpr::cast(parent)
-                .and_then(|method_call| highlight_method_call(sema, &method_call))
-                .unwrap_or_else(|| HighlightTag::Symbol(SymbolKind::Function).into());
-        }
-        FIELD_EXPR => {
-            let h = HighlightTag::Symbol(SymbolKind::Field);
-            let is_union = ast::FieldExpr::cast(parent)
-                .and_then(|field_expr| {
-                    let field = sema.resolve_field(&field_expr)?;
-                    Some(if let VariantDef::Union(_) = field.parent_def(sema.db) {
-                        true
-                    } else {
-                        false
-                    })
-                })
-                .unwrap_or(false);
-            if is_union {
-                h | HighlightModifier::Unsafe
-            } else {
-                h.into()
-            }
-        }
-        PATH_SEGMENT => {
-            let path = match parent.parent().and_then(ast::Path::cast) {
-                Some(it) => it,
-                _ => return default.into(),
-            };
-            let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
-                Some(it) => it,
-                _ => {
-                    // within path, decide whether it is module or adt by checking for uppercase name
-                    return if name.text().chars().next().unwrap_or_default().is_uppercase() {
-                        HighlightTag::Symbol(SymbolKind::Struct)
-                    } else {
-                        HighlightTag::Symbol(SymbolKind::Module)
-                    }
-                    .into();
-                }
-            };
-            let parent = match expr.syntax().parent() {
-                Some(it) => it,
-                None => return default.into(),
-            };
-
-            match parent.kind() {
-                CALL_EXPR => HighlightTag::Symbol(SymbolKind::Function).into(),
-                _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
-                    HighlightTag::Symbol(SymbolKind::Struct)
-                } else {
-                    HighlightTag::Symbol(SymbolKind::Const)
-                }
-                .into(),
-            }
-        }
-        _ => default.into(),
-    }
-}
diff --git a/crates/ide/src/syntax_highlighting/format.rs b/crates/ide/src/syntax_highlighting/format.rs
index 26416022b..a74ca844b 100644
--- a/crates/ide/src/syntax_highlighting/format.rs
+++ b/crates/ide/src/syntax_highlighting/format.rs
@@ -1,65 +1,51 @@
 //! Syntax highlighting for format macro strings.
 use syntax::{
     ast::{self, FormatSpecifier, HasFormatSpecifier},
-    AstNode, AstToken, SyntaxElement, SyntaxKind, SyntaxNode, TextRange,
+    AstNode, AstToken, TextRange,
 };
 
-use crate::{
-    syntax_highlighting::HighlightedRangeStack, HighlightTag, HighlightedRange, SymbolKind,
-};
-
-#[derive(Default)]
-pub(super) struct FormatStringHighlighter {
-    format_string: Option<SyntaxElement>,
-}
+use crate::{syntax_highlighting::highlights::Highlights, HlRange, HlTag, SymbolKind};
 
-impl FormatStringHighlighter {
-    pub(super) fn check_for_format_string(&mut self, parent: &SyntaxNode) {
-        // Check if macro takes a format string and remember it for highlighting later.
-        // The macros that accept a format string expand to a compiler builtin macros
-        // `format_args` and `format_args_nl`.
-        if let Some(name) = parent
-            .parent()
-            .and_then(ast::MacroCall::cast)
-            .and_then(|mc| mc.path())
-            .and_then(|p| p.segment())
-            .and_then(|s| s.name_ref())
-        {
-            match name.text().as_str() {
-                "format_args" | "format_args_nl" => {
-                    self.format_string = parent
-                        .children_with_tokens()
-                        .filter(|t| t.kind() != SyntaxKind::WHITESPACE)
-                        .nth(1)
-                        .filter(|e| ast::String::can_cast(e.kind()))
-                }
-                _ => {}
-            }
-        }
+pub(super) fn highlight_format_string(
+    stack: &mut Highlights,
+    string: &ast::String,
+    range: TextRange,
+) {
+    if is_format_string(string).is_none() {
+        return;
     }
-    pub(super) fn highlight_format_string(
-        &self,
-        range_stack: &mut HighlightedRangeStack,
-        string: &impl HasFormatSpecifier,
-        range: TextRange,
-    ) {
-        if self.format_string.as_ref() == Some(&SyntaxElement::from(string.syntax().clone())) {
-            range_stack.push();
-            string.lex_format_specifier(|piece_range, kind| {
-                if let Some(highlight) = highlight_format_specifier(kind) {
-                    range_stack.add(HighlightedRange {
-                        range: piece_range + range.start(),
-                        highlight: highlight.into(),
-                        binding_hash: None,
-                    });
-                }
+
+    string.lex_format_specifier(|piece_range, kind| {
+        if let Some(highlight) = highlight_format_specifier(kind) {
+            stack.add(HlRange {
+                range: piece_range + range.start(),
+                highlight: highlight.into(),
+                binding_hash: None,
             });
-            range_stack.pop();
         }
+    });
+}
+
+fn is_format_string(string: &ast::String) -> Option<()> {
+    let parent = string.syntax().parent();
+
+    let name = parent.parent().and_then(ast::MacroCall::cast)?.path()?.segment()?.name_ref()?;
+    if !matches!(name.text().as_str(), "format_args" | "format_args_nl") {
+        return None;
+    }
+
+    let first_literal = parent
+        .children_with_tokens()
+        .filter_map(|it| it.as_token().cloned().and_then(ast::String::cast))
+        .next()?;
+    if &first_literal != string {
+        return None;
     }
+
+    Some(())
 }
 
-fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HighlightTag> {
+fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HlTag> {
     Some(match kind {
         FormatSpecifier::Open
         | FormatSpecifier::Close
@@ -71,8 +57,10 @@ fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HighlightTag> {
         | FormatSpecifier::DollarSign
         | FormatSpecifier::Dot
         | FormatSpecifier::Asterisk
-        | FormatSpecifier::QuestionMark => HighlightTag::FormatSpecifier,
-        FormatSpecifier::Integer | FormatSpecifier::Zero => HighlightTag::NumericLiteral,
-        FormatSpecifier::Identifier => HighlightTag::Symbol(SymbolKind::Local),
+        | FormatSpecifier::QuestionMark => HlTag::FormatSpecifier,
+
+        FormatSpecifier::Integer | FormatSpecifier::Zero => HlTag::NumericLiteral,
+
+        FormatSpecifier::Identifier => HlTag::Symbol(SymbolKind::Local),
     })
 }
diff --git a/crates/ide/src/syntax_highlighting/highlight.rs b/crates/ide/src/syntax_highlighting/highlight.rs
new file mode 100644
index 000000000..34bae49a8
--- /dev/null
+++ b/crates/ide/src/syntax_highlighting/highlight.rs
@@ -0,0 +1,530 @@
+//! Computes color for a single element.
+