80 files changed, 1225 insertions, 1369 deletions
diff --git a/.travis.yml b/.travis.yml
index acf1af028..8d420f618 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,9 @@
+cache: cargo
 matrix:
  include:
    - language: rust
-      rust: stable
+      rust: beta
      script:
        - cargo gen-kinds --verify
        - cargo gen-tests --verify
diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
new file mode 100644
index 000000000..b497cc5d7
--- /dev/null
+++ b/ARCHITECTURE.md
@@ -0,0 +1,133 @@
+# Architecture
+This document describes high-level architecture of rust-analyzer.
+If you want to familiarize yourself with the code base, you are just
+in the right place!
+## Code generation
+Some of the components of this repository are generated through automatic
+processes. These are outlined below:
+- `gen-kinds`: The kinds of tokens are reused in several places, so a generator
+  is used. We use tera templates to generate the files listed below, based on
+  the grammar described in [grammar.ron]:
+  - [ast/generated.rs][ast generated] in `ra_syntax` based on
+    [ast/generated.tera.rs][ast source]
+  - [syntax_kinds/generated.rs][syntax_kinds generated] in `ra_syntax` based on
+    [syntax_kinds/generated.tera.rs][syntax_kinds source]
+[tera]: https://tera.netlify.com/
+[grammar.ron]: ./crates/ra_syntax/src/grammar.ron
+[ast generated]: ./crates/ra_syntax/src/ast/generated.rs
+[ast source]: ./crates/ra_syntax/src/ast/generated.rs.tera
+[syntax_kinds generated]: ./crates/ra_syntax/src/syntax_kinds/generated.rs
+[syntax_kinds source]: ./crates/ra_syntax/src/syntax_kinds/generated.rs.tera
+## Code Walk-Through
+### `crates/ra_syntax`
+Rust syntax tree structure and parser. See
+[RFC](https://github.com/rust-lang/rfcs/pull/2256) for some design
+notes.
+- [rowan](https://github.com/rust-analyzer/rowan) library is used for constructing syntax trees.
+- `grammar` module is the actual parser. It is a hand-written recursive descent parsers, which
+  produces a sequence of events like "start node X", "finish not Y". It works similarly to  [kotlin parser](https://github.com/JetBrains/kotlin/blob/4d951de616b20feca92f3e9cc9679b2de9e65195/compiler/frontend/src/org/jetbrains/kotlin/parsing/KotlinParsing.java),
+  which is a good source for inspiration for dealing with syntax errors and incomplete input. Original [libsyntax parser](https://github.com/rust-lang/rust/blob/6b99adeb11313197f409b4f7c4083c2ceca8a4fe/src/libsyntax/parse/parser.rs)
+  is what we use for the definition of the Rust language.
+- `parser_api/parser_impl` bridges the tree-agnostic parser from `grammar` with `rowan` trees.
+  This is the thing that turns a flat list of events into a tree (see `EventProcessor`)
+- `ast` a type safe API on top of the raw `rowan` tree.
+- `grammar.ron` RON description of the grammar, which is used to
+  generate `syntax_kinds` and `ast` modules, using `cargo gen-kinds` command.
+- `algo`: generic tree algorithms, including `walk` for O(1) stack
+  space tree traversal (this is cool) and `visit` for type-driven
+  visiting the nodes (this is double plus cool, if you understand how
+  `Visitor` works, you understand rust-analyzer).
+Test for ra_syntax are mostly data-driven: `tests/data/parser` contains a bunch of `.rs`
+(test vectors) and `.txt` files with corresponding syntax trees. During testing, we check
+`.rs` against `.txt`. If the `.txt` file is missing, it is created (this is how you update
+tests). Additionally, running `cargo gen-tests` will walk the grammar module and collect
+all `//test test_name` comments into files inside `tests/data` directory.
+See [#93](https://github.com/rust-analyzer/rust-analyzer/pull/93) for an example PR which
+fixes a bug in the grammar.
+### `crates/ra_editor`
+All IDE features which can be implemented if you only have access to a
+single file. `ra_editor` could be used to enhance editing of Rust code
+without the need to fiddle with build-systems, file
+synchronization and such.
+In a sense, `ra_editor` is just a bunch of pure functions which take a
+syntax tree as an input.
+The tests for `ra_editor` are `#[cfg(test)] mod tests` unit-tests spread
+throughout its modules.
+### `crates/salsa`
+An implementation of red-green incremental compilation algorithm from
+rust compiler. It makes all rust-analyzer features on-demand. To be replaced
+with `salsa-rs/salsa` soon.
+### `crates/ra_analysis`
+A stateful library for analyzing many Rust files as they change.
+`AnalysisHost` is a mutable entity (clojure's atom) which holds
+current state, incorporates changes and handles out `Analysis` --- an
+immutable consistent snapshot of world state at a point in time, which
+actually powers analysis.
+### `crates/ra_lsp_server`
+An LSP implementation which uses `ra_analysis` for managing state and
+`ra_editor` for actually doing useful stuff.
+See [#79](https://github.com/rust-analyzer/rust-analyzer/pull/79/) as an
+example of PR which adds a new feature to `ra_editor` and exposes it
+to `ra_lsp_server`.
+### `crates/cli`
+A CLI interface to rust-analyzer.
+### `crate/tools`
+Custom Cargo tasks used to develop rust-analyzer:
+- `cargo gen-kinds` -- generate `ast` and `syntax_kinds`
+- `cargo gen-tests` -- collect inline tests from grammar
+- `cargo install-code` -- build and install VS Code extension and server
+### `editors/code`
+VS Code plugin
+## Common workflows
+To try out VS Code extensions, run `cargo install-code`.  This installs both the
+`ra_lsp_server` binary and VS Code extension. To install only the binary, `use
+cargo install --path crates/ra_lsp_server --force`
+To see logs from the language server, set `RUST_LOG=info` env variable. To see
+all communication between the server and the client, use
+`RUST_LOG=gen_lsp_server=debug` (will print quite a bit of stuff).
+To run tests, just `cargo test`.
+To work on VS Code extension, launch code inside `editors/code` and use `F5` to
+launch/debug. To automatically apply formatter and linter suggestions, use `npm
+run fix`.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c952078cf..a2efc7afa 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,58 +1,18 @@
 The project is in its early stages: contributions are welcome and would be
 **very** helpful, but the project is not _yet_ optimized for contribution.
 Moreover, it is doubly experimental, so there's no guarantee that any work here
-would reach production. That said, here are some areas where contributions would
+would reach production.
-be **especially** welcome:
- Designing internal data structures: RFC only outlines the constraints, it's an
+To get an idea of how rust-analyzer works, take a look at the [ARCHITECTURE.md](./ARCHITECTURE.md)
-  open question how to satisfy them in the optimal way. See `ARCHITECTURE.md`
+document.
-  for current design questions.
- Porting libsyntax parser to rust-analyzer: currently rust-analyzer parses only
+Useful labels on the issue tracker:
-  a tiny subset of Rust. This should be fixed by porting parsing functions from
+  * [E-mentor](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-mentor)
-  libsyntax one by one. Take a look at the [libsyntax parser] for "what to port"
+    issues have links to the code in question and tests,
-  and at the [Kotlin parser] for "how to port".
+  * [E-easy](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy),
+    [E-medium](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-medium),
+    [E-hard](https://github.com/rust-analyzer/rust-analyzer/issues?q=is%3Aopen+is%3Aissue+label%3AE-hard),
+    labels are *estimates* for how hard would be to write a fix.
- Writing validators: by design, rust-analyzer is very lax about the input. For
+There's no formal PR check list: everything that passes CI (we use [bors](https://bors.tech/)) is valid,
-  example, the lexer happily accepts unclosed strings. The idea is that there
+but it's a good idea to write nice commit messages, test code thoroughly, maintain consistent style, etc.
-  should be a higher level visitor, which walks the syntax tree after parsing
-  and produces all the warnings. Alas, there's no such visitor yet :( Would you
-  like to write one? :)
- Creating tests: it would be tremendously helpful to read each of libsyntax and
-  rust-analyzer parser functions and crate a small separate test cases to cover
-  each and every edge case.
- Building stuff with rust-analyzer: it would be really cool to compile
-  rust-analyzer to WASM and add _client side_ syntax validation to rust
-  playground!
-Do take a look at the issue tracker.
-If you don't know where to start, or have _any_ questions or suggestions, don't
-hesitate to chat at [Gitter]!
-# Code generation
-Some of the components of this repository are generated through automatic
-processes. These are outlined below:
- `gen-kinds`: The kinds of tokens are reused in several places, so a generator
-  is used. This process uses [tera] to generate, using data in [grammar.ron],
-  the files:
-  - [ast/generated.rs][ast generated] in `ra_syntax` based on
-    [ast/generated.tera.rs][ast source]
-  - [syntax_kinds/generated.rs][syntax_kinds generated] in `ra_syntax` based on
-    [syntax_kinds/generated.tera.rs][syntax_kinds source]
-[libsyntax parser]:
-  https://github.com/rust-lang/rust/blob/6b99adeb11313197f409b4f7c4083c2ceca8a4fe/src/libsyntax/parse/parser.rs
-[kotlin parser]:
-  https://github.com/JetBrains/kotlin/blob/4d951de616b20feca92f3e9cc9679b2de9e65195/compiler/frontend/src/org/jetbrains/kotlin/parsing/KotlinParsing.java
-[gitter]: https://gitter.im/libsyntax2/Lobby
-[tera]: https://tera.netlify.com/
-[grammar.ron]: ./crates/ra_syntax/src/grammar.ron
-[ast generated]: ./crates/ra_syntax/src/ast/generated.rs
-[ast source]: ./crates/ra_syntax/src/ast/generated.tera.rs
-[syntax_kinds generated]: ./crates/ra_syntax/src/syntax_kinds/generated.rs
-[syntax_kinds source]: ./crates/ra_syntax/src/syntax_kinds/generated.tera.rs
diff --git a/Cargo.lock b/Cargo.lock
index 62feeb539..707257a31 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -15,6 +15,11 @@ dependencies = [
 ]
 [[package]]
+name = "arrayref"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+[[package]]
 name = "arrayvec"
 version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -68,6 +73,20 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
+name = "block-buffer"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "arrayref 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byte-tools 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+[[package]]
+name = "byte-tools"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+[[package]]
 name = "byteorder"
 version = "1.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -79,9 +98,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 1.0.31 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@@ -188,6 +207,16 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
+name = "derive-new"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+[[package]]
 name = "deunicode"
 version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -198,6 +227,14 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
+name = "digest"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+[[package]]
 name = "drop_bomb"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -229,13 +266,18 @@ name = "failure_derive"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "synstructure 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
+name = "fake-simd"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+[[package]]
 name = "flexi_logger"
 version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -277,9 +319,17 @@ dependencies = [
 "failure 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "languageserver-types 0.51.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 1.0.31 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+[[package]]
+name = "generic-array"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@@ -312,7 +362,7 @@ dependencies = [
 [[package]]
 name = "im"
-version = "12.1.0"
+version = "12.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -320,6 +370,11 @@ dependencies = [
 ]
 [[package]]
+name = "indexmap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+[[package]]
 name = "itertools"
 version = "0.7.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -343,11 +398,11 @@ version = "0.51.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-derive 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-derive 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 1.0.31 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
 "url 1.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "url_serde 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -383,6 +438,11 @@ dependencies = [
 ]
 [[package]]
+name = "maplit"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+[[package]]
 name = "matches"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -418,13 +478,13 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "num-derive"
-version = "0.2.2"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@@ -492,38 +552,57 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "pest"
-version = "1.0.6"
+version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ucd-trie 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 [[package]]
 name = "pest_derive"
-version = "1.0.8"
+version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "pest 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_generator 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
-name = "proc-macro2"
+name = "pest_generator"
-version = "0.4.19"
+version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_meta 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
-name = "quote"
+name = "pest_meta"
-version = "0.3.15"
+version = "2.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "maplit 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sha-1 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+[[package]]
+name = "proc-macro2"
+version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 [[package]]
 name = "quote"
 version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
@@ -532,7 +611,7 @@ version = "0.1.0"
 dependencies = [
 "crossbeam-channel 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "fst 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "im 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "im 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "once_cell 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -541,7 +620,7 @@ dependencies = [
 "rayon 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "relative-path 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "salsa 0.1.0",
+ "salsa 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "test_utils 0.1.0",
 ]
@@ -579,7 +658,7 @@ dependencies = [
 "failure 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "flexi_logger 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "gen_lsp_server 0.1.0",
- "im 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "im 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "languageserver-types 0.51.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "ra_analysis 0.1.0",
@@ -588,10 +667,10 @@ dependencies = [
 "rayon 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "relative-path 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
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diff --git a/README.md b/README.md
index 481d065b0..c3056bcfd 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,8 @@ functionality is provided via a language server.
 ## Quick Start
-Rust analyzer builds on stable Rust >= 1.29.0.
+Rust analyzer builds on Rust >= 1.30.0 (currently in beta) and uses
+the 2018 edition.
 ```
 # run tests
@@ -61,99 +62,20 @@ fold:
 * to quickly bootstrap usable and useful language server: solution
  that covers 80% of Rust code will be useful for IDEs, and will be
  vastly simpler than 100% solution.
-  
 * to understand how the consumer-side of compiler API should look like
  (especially it's on-demand aspects). If you have
  `get_expression_type` function, you can write a ton of purely-IDE
  features on top of it, even if the function is only partially
  correct. Plugin in the precise function afterwards should just make
  IDE features more reliable.
-  
 The long term plan is to merge with the mainline rustc compiler,
 probably around the HIR boundary? That is, use rust analyzer for
 parsing, macro expansion and related bits of name resolution, but
 leave the rest (including type inference and trait selection) to the
 existing rustc.
-## Code Walk-Through
-### `crates/ra_syntax`
-Rust syntax tree structure and parser. See
-[RFC](https://github.com/rust-lang/rfcs/pull/2256) for some design
-notes.
- `yellow`, red/green syntax tree, heavily inspired [by this](https://github.com/apple/swift/tree/ab68f0d4cbf99cdfa672f8ffe18e433fddc8b371/lib/Syntax)
- `grammar`, the actual parser
- `parser_api/parser_impl` bridges the tree-agnostic parser from `grammar` with `yellow` trees
- `grammar.ron` RON description of the grammar, which is used to
-  generate `syntax_kinds` and `ast` modules.
- `algo`: generic tree algorithms, including `walk` for O(1) stack
-  space tree traversal (this is cool) and `visit` for type-driven
-  visiting the nodes (this is double plus cool, if you understand how
-  `Visitor` works, you understand rust-analyzer).
-### `crates/ra_editor`
-All IDE features which can be implemented if you only have access to a
-single file. `ra_editor` could be used to enhance editing of Rust code
-without the need to fiddle with build-systems, file
-synchronization and such.
-In a sense, `ra_editor` is just a bunch of pure functions which take a
-syntax tree as an input.
-### `crates/salsa`
-An implementation of red-green incremental compilation algorithm from
-rust compiler. It makes all rust-analyzer features on-demand.
-### `crates/ra_analysis`
-A stateful library for analyzing many Rust files as they change.
-`AnalysisHost` is a mutable entity (clojure's atom) which holds
-current state, incorporates changes and handles out `Analysis` --- an
-immutable consistent snapshot of world state at a point in time, which
-actually powers analysis.
-### `crates/ra_lsp_server`
-An LSP implementation which uses `ra_analysis` for managing state and
-`ra_editor` for actually doing useful stuff.
-### `crates/cli`
-A CLI interface to libsyntax
-### `crate/tools`
-Code-gen tasks, used to develop rust-analyzer:
- `cargo gen-kinds` -- generate `ast` and `syntax_kinds`
- `cargo gen-tests` -- collect inline tests from grammar
- `cargo install-code` -- build and install VS Code extension and server
-### `editors/code`
-VS Code plugin
-## Performance
-Non-incremental, but seems pretty fast:
-```
-$ cargo build --release --package ra_cli
-$ wc -l ~/projects/rust/src/libsyntax/parse/parser.rs
-7546 /home/matklad/projects/rust/src/libsyntax/parse/parser.rs
-$ ./target/release/ra_cli parse < ~/projects/rust/src/libsyntax/parse/parser.rs --no-dump  > /dev/null
-parsing: 21.067065ms
-```
 ## Getting in touch
 @matklad can be found at Rust
@@ -161,6 +83,11 @@ parsing: 21.067065ms
 #ides-and-editors.
+## Contributing
+See [CONTRIBUTING.md](./CONTRIBUTING.md) and [ARCHITECTURE.md](./ARCHITECTURE.md)
 ## License
 Rust analyzer is primarily distributed under the terms of both the MIT
diff --git a/appveyor.yml b/appveyor.yml
index a6ba3b0e1..a32a1e7b8 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -2,7 +2,7 @@ os: Visual Studio 2015
 install:
  - curl https://win.rustup.rs/ --output rustup-init.exe
-  - rustup-init -yv --default-toolchain stable --default-host x86_64-pc-windows-msvc
+  - rustup-init -yv --default-toolchain beta --default-host x86_64-pc-windows-msvc
  - set PATH=%PATH%;%USERPROFILE%\.cargo\bin
  - rustc -vV
  - cargo -vV
diff --git a/crates/ra_analysis/Cargo.toml b/crates/ra_analysis/Cargo.toml
index a82e1761c..17b04182f 100644
--- a/crates/ra_analysis/Cargo.toml
+++ b/crates/ra_analysis/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "ra_analysis"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
@@ -14,7 +15,7 @@ fst = "0.3.1"
 im = "12.0.0"
 ra_syntax = { path = "../ra_syntax" }
 ra_editor = { path = "../ra_editor" }
-salsa = { path = "../salsa" }
+salsa = "0.5.0"
 rustc-hash = "1.0"
 [dev-dependencies]
diff --git a/crates/ra_analysis/src/db.rs b/crates/ra_analysis/src/db.rs
new file mode 100644
index 000000000..c69577233
--- /dev/null
+++ b/crates/ra_analysis/src/db.rs
@@ -0,0 +1,117 @@
+use std::{
+    fmt,
+    sync::Arc,
+    hash::{Hash, Hasher},
+};
+use salsa;
+use rustc_hash::FxHashSet;
+use ra_syntax::File;
+use ra_editor::{LineIndex};
+use crate::{
+    symbol_index::SymbolIndex,
+    module_map::{ModulesDatabase, ModuleTreeQuery, ModuleDescriptorQuery},
+    FileId, FileResolverImp,
+};
+#[derive(Default)]
+pub(crate) struct RootDatabase {
+    runtime: salsa::runtime::Runtime<RootDatabase>,
+}
+impl fmt::Debug for RootDatabase {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.write_str("RootDatabase { ... }")
+    }
+}
+impl salsa::Database for RootDatabase {
+    fn salsa_runtime(&self) -> &salsa::runtime::Runtime<RootDatabase> {
+        &self.runtime
+    }
+}
+impl salsa::ParallelDatabase for RootDatabase {
+    fn fork(&self) -> Self {
+        RootDatabase {
+            runtime: self.runtime.fork(),
+        }
+    }
+}
+impl Clone for RootDatabase {
+    fn clone(&self) -> RootDatabase {
+        salsa::ParallelDatabase::fork(self)
+    }
+}
+salsa::database_storage! {
+    pub(crate) struct RootDatabaseStorage for RootDatabase {
+        impl FilesDatabase {
+            fn file_text() for FileTextQuery;
+            fn file_set() for FileSetQuery;
+        }
+        impl SyntaxDatabase {
+            fn file_syntax() for FileSyntaxQuery;
+            fn file_lines() for FileLinesQuery;
+            fn file_symbols() for FileSymbolsQuery;
+        }
+        impl ModulesDatabase {
+            fn module_tree() for ModuleTreeQuery;
+            fn module_descriptor() for ModuleDescriptorQuery;
+        }
+    }
+}
+salsa::query_group! {
+    pub(crate) trait FilesDatabase: salsa::Database {
+        fn file_text(file_id: FileId) -> Arc<String> {
+            type FileTextQuery;
+            storage input;
+        }
+        fn file_set(key: ()) -> Arc<FileSet> {
+            type FileSetQuery;
+            storage input;
+        }
+    }
+}
+#[derive(Default, Debug, PartialEq, Eq)]
+pub(crate) struct FileSet {
+    pub(crate) files: FxHashSet<FileId>,
+    pub(crate) resolver: FileResolverImp,
+}
+impl Hash for FileSet {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        let mut files = self.files.iter().cloned().collect::<Vec<_>>();
+        files.sort();
+        files.hash(hasher);
+    }
+}
+salsa::query_group! {
+    pub(crate) trait SyntaxDatabase: FilesDatabase {
+        fn file_syntax(file_id: FileId) -> File {
+            type FileSyntaxQuery;
+        }
+        fn file_lines(file_id: FileId) -> Arc<LineIndex> {
+            type FileLinesQuery;
+        }
+        fn file_symbols(file_id: FileId) -> Arc<SymbolIndex> {
+            type FileSymbolsQuery;
+        }
+    }
+}
+fn file_syntax(db: &impl SyntaxDatabase, file_id: FileId) -> File {
+    let text = db.file_text(file_id);
+    File::parse(&*text)
+}
+fn file_lines(db: &impl SyntaxDatabase, file_id: FileId) -> Arc<LineIndex> {
+    let text = db.file_text(file_id);
+    Arc::new(LineIndex::new(&*text))
+}
+fn file_symbols(db: &impl SyntaxDatabase, file_id: FileId) -> Arc<SymbolIndex> {
+    let syntax = db.file_syntax(file_id);
+    Arc::new(SymbolIndex::for_file(file_id, syntax))
+}
diff --git a/crates/ra_analysis/src/db/imp.rs b/crates/ra_analysis/src/db/imp.rs
deleted file mode 100644
index 36f6cf290..000000000
--- a/crates/ra_analysis/src/db/imp.rs
+++ /dev/null
@@ -1,153 +0,0 @@
-use std::{
-    sync::Arc,
-    any::Any,
-    hash::{Hash, Hasher},
-    collections::hash_map::{DefaultHasher},
-    iter,
-};
-use rustc_hash::FxHashMap;
-use salsa;
-use {FileId, imp::FileResolverImp};
-use super::{State, Query, QueryCtx};
-pub(super) type Data = Arc<Any + Send + Sync + 'static>;
-#[derive(Debug)]
-pub(super) struct Db {
-    names: Arc<FxHashMap<salsa::QueryTypeId, &'static str>>,
-    pub(super) imp: salsa::Db<State, Data>,
-}
-impl Db {
-    pub(super) fn new(mut reg: QueryRegistry) -> Db {
-        let config = reg.config.take().unwrap();
-        Db {
-            names: Arc::new(reg.names),
-            imp: salsa::Db::new(config, State::default())
-        }
-    }
-    pub(crate) fn with_changes(&self, new_state: State, changed_files: &[FileId], resolver_changed: bool) -> Db {
-        let names = self.names.clone();
-        let mut invalidations = salsa::Invalidations::new();
-        invalidations.invalidate(FILE_TEXT, changed_files.iter().map(hash).map(salsa::InputFingerprint));
-        if resolver_changed {
-            invalidations.invalidate(FILE_SET, iter::once(salsa::InputFingerprint(hash(&()))));
-        } else {
-            invalidations.invalidate(FILE_SET, iter::empty());
-        }
-        let imp = self.imp.with_ground_data(
-            new_state,
-            invalidations,
-        );
-        Db { names, imp }
-    }
-    pub(super) fn extract_trace(&self, ctx: &salsa::QueryCtx<State, Data>) -> Vec<&'static str> {
-        ctx.trace().into_iter().map(|it| self.names[&it]).collect()
-    }
-}
-pub(crate) trait EvalQuery {
-    type Params;
-    type Output;
-    fn query_type(&self) -> salsa::QueryTypeId;
-    fn f(&self) -> salsa::QueryFn<State, Data>;
-    fn get(&self, &QueryCtx, Self::Params) -> Arc<Self::Output>;
-}
-impl<T, R> EvalQuery for Query<T, R>
-where
-    T: Hash + Send + Sync + 'static,
-    R: Hash + Send + Sync + 'static,
-{
-    type Params = T;
-    type Output = R;
-    fn query_type(&self) -> salsa::QueryTypeId {
-        salsa::QueryTypeId(self.0)
-    }
-    fn f(&self) -> salsa::QueryFn<State, Data> {
-        let f = self.1;
-        Box::new(move |ctx, data| {
-            let ctx = QueryCtx { imp: ctx };
-            let data: &T = data.downcast_ref().unwrap();
-            let res = f(ctx, data);
-            let h = hash(&res);
-            (Arc::new(res), salsa::OutputFingerprint(h))
-        })
-    }
-    fn get(&self, ctx: &QueryCtx, params: Self::Params) -> Arc<Self::Output> {
-        let query_id = salsa::QueryId(
-            self.query_type(),
-            salsa::InputFingerprint(hash(&params)),
-        );
-        let res = ctx.imp.get(query_id, Arc::new(params));
-        res.downcast().unwrap()
-    }
-}
-pub(super) struct QueryRegistry {
-    config: Option<salsa::QueryConfig<State, Data>>,
-    names: FxHashMap<salsa::QueryTypeId, &'static str>,
-}
-impl QueryRegistry {
-    pub(super) fn new() -> QueryRegistry {
-        let mut config = salsa::QueryConfig::<State, Data>::new();
-        config = config.with_ground_query(
-            FILE_TEXT, Box::new(|state, params| {
-                let file_id: &FileId = params.downcast_ref().unwrap();
-                let res = state.file_map[file_id].clone();
-                let fingerprint = salsa::OutputFingerprint(hash(&res));
-                (res, fingerprint)
-            })
-        );
-        config = config.with_ground_query(
-            FILE_SET, Box::new(|state, _params| {
-                let file_ids: Vec<FileId> = state.file_map.keys().cloned().collect();
-                let hash = hash(&file_ids);
-                let file_resolver = state.file_resolver.clone();
-                let res = (file_ids, file_resolver);
-                let fingerprint = salsa::OutputFingerprint(hash);
-                (Arc::new(res), fingerprint)
-            })
-        );
-        let mut names = FxHashMap::default();
-        names.insert(FILE_TEXT, "FILE_TEXT");
-        names.insert(FILE_SET, "FILE_SET");
-        QueryRegistry { config: Some(config), names }
-    }
-    pub(super) fn add<Q: EvalQuery>(&mut self, q: Q, name: &'static str) {
-        let id = q.query_type();
-        let prev = self.names.insert(id, name);
-        assert!(prev.is_none(), "duplicate query: {:?}", id);
-        let config = self.config.take().unwrap();
-        let config = config.with_query(id, q.f());
-        self.config= Some(config);
-    }
-}
-fn hash<T: Hash>(x: &T) -> u64 {
-    let mut hasher = DefaultHasher::new();
-    x.hash(&mut hasher);
-    hasher.finish()
-}
-const FILE_TEXT: salsa::QueryTypeId = salsa::QueryTypeId(0);
-pub(super) fn file_text(ctx: QueryCtx, file_id: FileId) -> Arc<String> {
-    let query_id = salsa::QueryId(
-        FILE_TEXT,
-        salsa::InputFingerprint(hash(&file_id)),
-    );
-    let res = ctx.imp.get(query_id, Arc::new(file_id));
-    res.downcast().unwrap()
-}
-const FILE_SET: salsa::QueryTypeId = salsa::QueryTypeId(1);
-pub(super) fn file_set(ctx: QueryCtx) -> Arc<(Vec<FileId>, FileResolverImp)> {
-    let query_id = salsa::QueryId(
-        FILE_SET,
-        salsa::InputFingerprint(hash(&())),
-    );
-    let res = ctx.imp.get(query_id, Arc::new(()));
-    res.downcast().unwrap()
-}
diff --git a/crates/ra_analysis/src/db/mod.rs b/crates/ra_analysis/src/db/mod.rs
deleted file mode 100644
index 22769d112..000000000
--- a/crates/ra_analysis/src/db/mod.rs
+++ /dev/null
@@ -1,85 +0,0 @@
-mod imp;
-use std::{
-    sync::Arc,
-};
-use im;
-use salsa;
-use {FileId, imp::FileResolverImp};
-#[derive(Debug, Default, Clone)]
-pub(crate) struct State {
-    pub(crate) file_map: im::HashMap<FileId, Arc<String>>,
-    pub(crate) file_resolver: FileResolverImp
-}
-#[derive(Debug)]
-pub(crate) struct Db {
-    imp: imp::Db,
-}
-#[derive(Clone, Copy)]
-pub(crate) struct QueryCtx<'a> {
-    imp: &'a salsa::QueryCtx<State, imp::Data>,
-}
-pub(crate) struct Query<T, R>(pub(crate) u16, pub(crate) fn(QueryCtx, &T) -> R);
-pub(crate) struct QueryRegistry {
-    imp: imp::QueryRegistry,
-}
-impl Default for Db {
-    fn default() -> Db {
-        Db::new()
-    }
-}
-impl Db {
-    pub(crate) fn new() -> Db {
-        let reg = QueryRegistry::new();
-        Db { imp: imp::Db::new(reg.imp) }
-    }
-    pub(crate) fn state(&self) -> &State {
-        self.imp.imp.ground_data()
-    }
-    pub(crate) fn with_changes(&self, new_state: State, changed_files: &[FileId], resolver_changed: bool) -> Db {
-        Db { imp: self.imp.with_changes(new_state, changed_files, resolver_changed) }
-    }
-    pub(crate) fn make_query<F: FnOnce(QueryCtx) -> R, R>(&self, f: F) -> R {
-        let ctx = QueryCtx { imp: &self.imp.imp.query_ctx() };
-        f(ctx)
-    }
-    #[allow(unused)]
-    pub(crate) fn trace_query<F: FnOnce(QueryCtx) -> R, R>(&self, f: F) -> (R, Vec<&'static str>) {
-        let ctx = QueryCtx { imp: &self.imp.imp.query_ctx() };
-        let res = f(ctx);
-        let trace = self.imp.extract_trace(ctx.imp);
-        (res, trace)
-    }
-}
-impl<'a> QueryCtx<'a> {
-    pub(crate) fn get<Q: imp::EvalQuery>(&self, q: Q, params: Q::Params) -> Arc<Q::Output> {
-        q.get(self, params)
-    }
-}
-pub(crate) fn file_text(ctx: QueryCtx, file_id: FileId) -> Arc<String> {
-    imp::file_text(ctx, file_id)
-}
-pub(crate) fn file_set(ctx: QueryCtx) -> Arc<(Vec<FileId>, FileResolverImp)> {
-    imp::file_set(ctx)
-}
-impl QueryRegistry {
-    fn new() -> QueryRegistry {
-        let mut reg = QueryRegistry { imp: imp::QueryRegistry::new() };
-        ::queries::register_queries(&mut reg);
-        ::module_map::register_queries(&mut reg);
-        reg
-    }
-    pub(crate) fn add<Q: imp::EvalQuery>(&mut self, q: Q, name: &'static str) {
-        self.imp.add(q, name)
-    }
-}
diff --git a/crates/ra_analysis/src/descriptors.rs b/crates/ra_analysis/src/descriptors.rs
index 0731b5572..8d9f38ca5 100644
--- a/crates/ra_analysis/src/descriptors.rs
+++ b/crates/ra_analysis/src/descriptors.rs
@@ -4,14 +4,15 @@ use std::{
 use relative_path::RelativePathBuf;
 use ra_syntax::{
    SmolStr,
-    ast::{self, NameOwner},
+    ast::{self, NameOwner, AstNode},
+    text_utils::is_subrange
 };
-use {
+use crate::{
    FileId,
    imp::FileResolverImp,
 };
-#[derive(Debug, Hash)]
+#[derive(Debug, PartialEq, Eq, Hash)]
 pub struct ModuleDescriptor {
    pub submodules: Vec<Submodule>
 }
@@ -42,7 +43,7 @@ pub struct Submodule {
    pub name: SmolStr,
 }
-#[derive(Hash, Debug)]
+#[derive(Debug, PartialEq, Eq, Hash)]
 pub(crate) struct ModuleTreeDescriptor {
    nodes: Vec<NodeData>,
    links: Vec<LinkData>,
@@ -51,7 +52,7 @@ pub(crate) struct ModuleTreeDescriptor {
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 struct Node(usize);
-#[derive(Hash, Debug)]
+#[derive(Hash, Debug, PartialEq, Eq)]
 struct NodeData {
    file_id: FileId,
    links: Vec<Link>,
@@ -60,7 +61,7 @@ struct NodeData {
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 pub(crate) struct Link(usize);
-#[derive(Hash, Debug)]
+#[derive(Hash, Debug, PartialEq, Eq)]
 struct LinkData {
    owner: Node,
    name: SmolStr,
@@ -69,7 +70,7 @@ struct LinkData {
 }
-#[derive(Clone, Debug, Hash)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub enum Problem {
    UnresolvedModule {
        candidate: RelativePathBuf,
@@ -218,3 +219,56 @@ fn resolve_submodule(
    }
    (points_to, problem)
 }
+#[derive(Debug, Clone)]
+pub struct FnDescriptor {
+    pub name: String,
+    pub label : String,
+    pub ret_type: Option<String>,
+    pub params: Vec<String>,
+}
+impl FnDescriptor {
+    pub fn new(node: ast::FnDef) -> Option<Self> {
+        let name = node.name()?.text().to_string();
+        // Strip the body out for the label.
+        let label : String = if let Some(body) = node.body() {
+            let body_range = body.syntax().range();
+            let label : String = node.syntax().children()
+                .filter(|child| !is_subrange(body_range, child.range()))
+                .map(|node| node.text().to_string())
+                .collect();
+            label
+        } else {
+            node.syntax().text().to_string()
+        };
+        let params = FnDescriptor::param_list(node);
+        let ret_type = node.ret_type().map(|r| r.syntax().text().to_string());
+        Some(FnDescriptor {
+            name,
+            ret_type,
+            params,
+            label
+        })
+    }
+    fn param_list(node: ast::FnDef) -> Vec<String> {
+        let mut res = vec![];
+        if let Some(param_list) = node.param_list() {
+            if let Some(self_param) = param_list.self_param() {
+                res.push(self_param.syntax().text().to_string())
+            }
+            // Maybe use param.pat here? See if we can just extract the name?
+            //res.extend(param_list.params().map(|p| p.syntax().text().to_string()));
+            res.extend(param_list.params()
+                .filter_map(|p| p.pat())
+                .map(|pat| pat.syntax().text().to_string())
+            );
+        }
+        res
+    }
+}
diff --git a/crates/ra_analysis/src/imp.rs b/crates/ra_analysis/src/imp.rs
index 47bc0032b..5efcaeca0 100644
--- a/crates/ra_analysis/src/imp.rs
+++ b/crates/ra_analysis/src/imp.rs
@@ -1,8 +1,8 @@
 use std::{
    sync::{
        Arc,
-        atomic::{AtomicBool, Ordering::SeqCst},
    },
+    hash::{Hash, Hasher},
    fmt,
    collections::VecDeque,
    iter,
@@ -12,24 +12,38 @@ use relative_path::RelativePath;
 use rustc_hash::FxHashSet;
 use ra_editor::{self, FileSymbol, LineIndex, find_node_at_offset, LocalEdit, resolve_local_name};
 use ra_syntax::{
-    TextUnit, TextRange, SmolStr, File, AstNode,
+    TextUnit, TextRange, SmolStr, File, AstNode, SyntaxNodeRef,
    SyntaxKind::*,
-    ast::{self, NameOwner},
+    ast::{self, NameOwner, ArgListOwner, Expr},
 };
-use {
+use crate::{
    FileId, FileResolver, Query, Diagnostic, SourceChange, SourceFileEdit, Position, FileSystemEdit,
    JobToken, CrateGraph, CrateId,
    roots::{SourceRoot, ReadonlySourceRoot, WritableSourceRoot},
-    descriptors::{ModuleTreeDescriptor, Problem},
+    descriptors::{FnDescriptor, ModuleTreeDescriptor, Problem},
 };
 #[derive(Clone, Debug)]
 pub(crate) struct FileResolverImp {
    inner: Arc<FileResolver>
 }
+impl PartialEq for FileResolverImp {
+    fn eq(&self, other: &FileResolverImp) -> bool {
+        self.inner() == other.inner()
+    }
+}
+impl Eq for FileResolverImp {
+}
+impl Hash for FileResolverImp {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        self.inner().hash(hasher);
+    }
+}
 impl FileResolverImp {
    pub(crate) fn new(inner: Arc<FileResolver>) -> FileResolverImp {
        FileResolverImp { inner }
@@ -40,6 +54,9 @@ impl FileResolverImp {
    pub(crate) fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId> {
        self.inner.resolve(file_id, path)
    }
+    fn inner(&self) -> *const FileResolver {
+        &*self.inner
+    }
 }
 impl Default for FileResolverImp {
@@ -60,29 +77,27 @@ impl Default for FileResolverImp {
 #[derive(Debug)]
 pub(crate) struct AnalysisHostImpl {
-    data: Arc<WorldData>
+    data: WorldData
 }
 impl AnalysisHostImpl {
    pub fn new() -> AnalysisHostImpl {
        AnalysisHostImpl {
-            data: Arc::new(WorldData::default()),
+            data: WorldData::default(),
        }
    }
    pub fn analysis(&self) -> AnalysisImpl {
        AnalysisImpl {
-            needs_reindex: AtomicBool::new(false),
            data: self.data.clone(),
        }
    }
    pub fn change_files(&mut self, changes: &mut dyn Iterator<Item=(FileId, Option<String>)>) {
-        let data = self.data_mut();
+        self.data_mut()
-        data.root = Arc::new(data.root.apply_changes(changes, None));
+            .root.apply_changes(changes, None);
    }
    pub fn set_file_resolver(&mut self, resolver: FileResolverImp) {
-        let data = self.data_mut();
+        self.data_mut()
-        data.file_resolver = resolver.clone();
+            .root.apply_changes(&mut iter::empty(), Some(resolver));
-        data.root = Arc::new(data.root.apply_changes(&mut iter::empty(), Some(resolver)));
    }
    pub fn set_crate_graph(&mut self, graph: CrateGraph) {
        let mut visited = FxHashSet::default();
@@ -97,34 +112,24 @@ impl AnalysisHostImpl {
        self.data_mut().libs.push(Arc::new(root));
    }
    fn data_mut(&mut self) -> &mut WorldData {
-        Arc::make_mut(&mut self.data)
+        &mut self.data
    }
 }
 pub(crate) struct AnalysisImpl {
-    needs_reindex: AtomicBool,
+    data: WorldData,
-    data: Arc<WorldData>,
 }
 impl fmt::Debug for AnalysisImpl {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        (&*self.data).fmt(f)
+        self.data.fmt(f)
-    }
-}
-impl Clone for AnalysisImpl {
-    fn clone(&self) -> AnalysisImpl {
-        AnalysisImpl {
-            needs_reindex: AtomicBool::new(self.needs_reindex.load(SeqCst)),
-            data: Arc::clone(&self.data),
-        }
    }
 }
 impl AnalysisImpl {
    fn root(&self, file_id: FileId) -> &SourceRoot {
        if self.data.root.contains(file_id) {
-            return &*self.data.root;
+            return &self.data.root;
        }
        &**self.data.libs.iter().find(|it| it.contains(file_id)).unwrap()
    }
@@ -306,6 +311,68 @@ impl AnalysisImpl {
            .collect()
    }
+    pub fn resolve_callable(&self, file_id: FileId, offset: TextUnit, token: &JobToken)
+        -> Option<(FnDescriptor, Option<usize>)> {
+        let root = self.root(file_id);
+        let file = root.syntax(file_id);
+        let syntax = file.syntax();
+        // Find the calling expression and it's NameRef
+        let calling_node = FnCallNode::with_node(syntax, offset)?;
+        let name_ref = calling_node.name_ref()?;
+        // Resolve the function's NameRef (NOTE: this isn't entirely accurate).
+        let file_symbols = self.index_resolve(name_ref, token);
+        for (_, fs) in file_symbols {
+            if fs.kind == FN_DEF {
+                if let Some(fn_def) = find_node_at_offset(syntax, fs.node_range.start()) {
+                    if let Some(descriptor) = FnDescriptor::new(fn_def) {
+                        // If we have a calling expression let's find which argument we are on
+                        let mut current_parameter = None;
+                        let num_params = descriptor.params.len();
+                        let has_self = fn_def.param_list()
+                            .and_then(|l| l.self_param())
+                            .is_some();
+                        if num_params == 1 {
+                            if !has_self {
+                                current_parameter = Some(1);
+                            }
+                        } else if num_params > 1 {
+                            // Count how many parameters into the call we are.
+                            // TODO: This is best effort for now and should be fixed at some point.
+                            // It may be better to see where we are in the arg_list and then check
+                            // where offset is in that list (or beyond).
+                            // Revisit this after we get documentation comments in.
+                            if let Some(ref arg_list) = calling_node.arg_list() {
+                                let start = arg_list.syntax().range().start();
+                                let range_search = TextRange::from_to(start, offset);
+                                let mut commas: usize = arg_list.syntax().text()
+                                    .slice(range_search).to_string()
+                                    .matches(",")
+                                    .count();
+                                // If we have a method call eat the first param since it's just self.
+                                if has_self {
+                                    commas = commas + 1;
+                                }
+                                current_parameter = Some(commas);
+                            }
+                        }
+                        return Some((descriptor, current_parameter));
+                    }
+                }
+            }
+        }
+        None
+    }
    fn index_resolve(&self, name_ref: ast::NameRef, token: &JobToken) -> Vec<(FileId, FileSymbol)> {
        let name = name_ref.text();
        let mut query = Query::new(name.to_string());
@@ -325,9 +392,8 @@ impl AnalysisImpl {
 #[derive(Default, Clone, Debug)]
 struct WorldData {
-    file_resolver: FileResolverImp,
    crate_graph: CrateGraph,
-    root: Arc<WritableSourceRoot>,
+    root: WritableSourceRoot,
    libs: Vec<Arc<ReadonlySourceRoot>>,
 }
@@ -355,3 +421,46 @@ impl CrateGraph {
        Some(crate_id)
    }
 }
+enum FnCallNode<'a> {
+    CallExpr(ast::CallExpr<'a>),
+    MethodCallExpr(ast::MethodCallExpr<'a>)
+}
+impl<'a> FnCallNode<'a> {
+    pub fn with_node(syntax: SyntaxNodeRef, offset: TextUnit) -> Option<FnCallNode> {
+        if let Some(expr) = find_node_at_offset::<ast::CallExpr>(syntax, offset) {
+            return Some(FnCallNode::CallExpr(expr));
+        }
+        if let Some(expr) = find_node_at_offset::<ast::MethodCallExpr>(syntax, offset) {
+            return Some(FnCallNode::MethodCallExpr(expr));
+        }
+        None
+    }
+    pub fn name_ref(&self) -> Option<ast::NameRef> {
+        match *self {
+            FnCallNode::CallExpr(call_expr) => {
+                Some(match call_expr.expr()? {
+                    Expr::PathExpr(path_expr) => {
+                        path_expr.path()?.segment()?.name_ref()?
+                    },
+                    _ => return None
+                })
+            },
+            FnCallNode::MethodCallExpr(call_expr) => {
+                call_expr.syntax().children()
+                    .filter_map(ast::NameRef::cast)
+                    .nth(0)
+            }
+        }
+    }
+    pub fn arg_list(&self) -> Option<ast::ArgList> {
+        match *self {
+            FnCallNode::CallExpr(expr) => expr.arg_list(),
+            FnCallNode::MethodCallExpr(expr) => expr.arg_list()
+        }
+    }
+}
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 849fd93e4..d8b355a81 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -19,7 +19,6 @@ mod imp;
 mod job;
 mod roots;
 mod db;
-mod queries;
 mod descriptors;
 use std::{
@@ -29,15 +28,18 @@ use std::{
 use relative_path::{RelativePath, RelativePathBuf};
 use ra_syntax::{File, TextRange, TextUnit, AtomEdit};
-use imp::{AnalysisImpl, AnalysisHostImpl, FileResolverImp};
 use rustc_hash::FxHashMap;
+use crate::imp::{AnalysisImpl, AnalysisHostImpl, FileResolverImp};
 pub use ra_editor::{
    StructureNode, LineIndex, FileSymbol,
    Runnable, RunnableKind, HighlightedRange, CompletionItem,
    Fold, FoldKind
 };
-pub use job::{JobToken, JobHandle};
+pub use crate::{
+    job::{JobToken, JobHandle},
+    descriptors::FnDescriptor,
+};
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct FileId(pub u32);
@@ -159,7 +161,7 @@ impl Query {
    }
 }
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct Analysis {
    imp: AnalysisImpl
 }
@@ -236,6 +238,11 @@ impl Analysis {
        let file = self.imp.file_syntax(file_id);
        ra_editor::folding_ranges(&file)
    }
+    pub fn resolve_callable(&self, file_id: FileId, offset: TextUnit, token: &JobToken)
+        -> Option<(FnDescriptor, Option<usize>)> {
+        self.imp.resolve_callable(file_id, offset, token)
+    }
 }
 #[derive(Debug)]
@@ -250,3 +257,9 @@ impl LibraryData {
        LibraryData { root }
    }
 }
+#[test]
+fn analysis_is_send() {
+    fn is_send<T: Send>() {}
+    is_send::<Analysis>();
+}
diff --git a/crates/ra_analysis/src/module_map.rs b/crates/ra_analysis/src/module_map.rs
index a21f55fff..c1799e3d4 100644
--- a/crates/ra_analysis/src/module_map.rs
+++ b/crates/ra_analysis/src/module_map.rs
@@ -1,157 +1,34 @@
 use std::sync::Arc;
-use {
+use crate::{
    FileId,
-    db::{
+    db::{SyntaxDatabase},
-        Query, QueryRegistry, QueryCtx,
-        file_set
-    },
-    queries::file_syntax,
    descriptors::{ModuleDescriptor, ModuleTreeDescriptor},
 };
-pub(crate) fn register_queries(reg: &mut QueryRegistry) {
+salsa::query_group! {
-    reg.add(MODULE_DESCR, "MODULE_DESCR");
+    pub(crate) trait ModulesDatabase: SyntaxDatabase {
-    reg.add(MODULE_TREE, "MODULE_TREE");
+        fn module_tree(key: ()) -> Arc<ModuleTreeDescriptor> {
-}
+            type ModuleTreeQuery;
-pub(crate) fn module_tree(ctx: QueryCtx) -> Arc<ModuleTreeDescriptor> {
-    ctx.get(MODULE_TREE, ())
-}
-const MODULE_DESCR: Query<FileId, ModuleDescriptor> = Query(30, |ctx, &file_id| {
-    let file = file_syntax(ctx, file_id);
-    ModuleDescriptor::new(file.ast())
-});
-const MODULE_TREE: Query<(), ModuleTreeDescriptor> = Query(31, |ctx, _| {
-    let file_set = file_set(ctx);
-    let mut files = Vec::new();
-    for &file_id in file_set.0.iter() {
-        let module_descr = ctx.get(MODULE_DESCR, file_id);
-        files.push((file_id, module_descr));
-    }
-    ModuleTreeDescriptor::new(files.iter().map(|(file_id, descr)| (*file_id, &**descr)), &file_set.1)
-});
-#[cfg(test)]
-mod tests {
-    use std::collections::HashMap;
-    use im;
-    use relative_path::{RelativePath, RelativePathBuf};
-    use {
-        db::{Db},
-        imp::FileResolverImp,
-        FileId, FileResolver,
-    };
-    use super::*;
-    #[derive(Debug)]
-    struct FileMap(im::HashMap<FileId, RelativePathBuf>);
-    impl FileResolver for FileMap {
-        fn file_stem(&self, file_id: FileId) -> String {
-            self.0[&file_id].file_stem().unwrap().to_string()
        }
-        fn resolve(&self, file_id: FileId, rel: &RelativePath) -> Option<FileId> {
+        fn module_descriptor(file_id: FileId) -> Arc<ModuleDescriptor> {
-            let path = self.0[&file_id].join(rel).normalize();
+            type ModuleDescriptorQuery;
-            self.0.iter()
-                .filter_map(|&(id, ref p)| Some(id).filter(|_| p == &path))
-                .next()
        }
    }
+}
-    struct Fixture {
-        next_file_id: u32,
-        fm: im::HashMap<FileId, RelativePathBuf>,
-        db: Db,
-    }
-    impl Fixture {
-        fn new() -> Fixture {
-            Fixture {
-                next_file_id: 1,
-                fm: im::HashMap::new(),
-                db: Db::new(),
-            }
-        }
-        fn add_file(&mut self, path: &str, text: &str) -> FileId {
-            assert!(path.starts_with("/"));
-            let file_id = FileId(self.next_file_id);
-            self.next_file_id += 1;
-            self.fm.insert(file_id, RelativePathBuf::from(&path[1..]));
-            let mut new_state = self.db.state().clone();
-            new_state.file_map.insert(file_id, Arc::new(text.to_string()));
-            new_state.file_resolver = FileResolverImp::new(
-                Arc::new(FileMap(self.fm.clone()))
-            );
-            self.db = self.db.with_changes(new_state, &[file_id], true);
-            file_id
-        }
-        fn remove_file(&mut self, file_id: FileId) {
-            self.fm.remove(&file_id);
-            let mut new_state = self.db.state().clone();
-            new_state.file_map.remove(&file_id);
-            new_state.file_resolver = FileResolverImp::new(
-                Arc::new(FileMap(self.fm.clone()))
-            );
-            self.db = self.db.with_changes(new_state, &[file_id], true);
-        }
-        fn change_file(&mut self, file_id: FileId, new_text: &str) {
-            let mut new_state = self.db.state().clone();
-            new_state.file_map.insert(file_id, Arc::new(new_text.to_string()));
-            self.db = self.db.with_changes(new_state, &[file_id], false);
-        }
-        fn check_parent_modules(
-            &self,
-            file_id: FileId,
-            expected: &[FileId],
-            queries: &[(&'static str, u64)]
-        ) {
-            let (tree, events) = self.db.trace_query(|ctx| module_tree(ctx));
-            let actual = tree.parent_modules(file_id)
-                .into_iter()
-                .map(|link| link.owner(&tree))
-                .collect::<Vec<_>>();
-            assert_eq!(actual.as_slice(), expected);
-            let mut counts = HashMap::new();
-            events.into_iter()
-               .for_each(|event| *counts.entry(event).or_insert(0) += 1);
-            for &(query_id, expected_count) in queries.iter() {
-                let actual_count = *counts.get(&query_id).unwrap_or(&0);
-                assert_eq!(
-                    actual_count,
-                    expected_count,
-                    "counts for {} differ",
-                    query_id,
-                )
-            }
-        }
-    }
-    #[test]
-    fn test_parent_module() {
-        let mut f = Fixture::new();
-        let foo = f.add_file("/foo.rs", "");
-        f.check_parent_modules(foo, &[], &[("MODULE_DESCR", 1)]);
-        let lib = f.add_file("/lib.rs", "mod foo;");
-        f.check_parent_modules(foo, &[lib], &[("MODULE_DESCR", 1)]);
-        f.check_parent_modules(foo, &[lib], &[("MODULE_DESCR", 0)]);
-        f.change_file(lib, "");
-        f.check_parent_modules(foo, &[], &[("MODULE_DESCR", 1)]);
-        f.change_file(lib, "mod foo;");
-        f.check_parent_modules(foo, &[lib], &[("MODULE_DESCR", 1)]);
-        f.change_file(lib, "mod bar;");
-        f.check_parent_modules(foo, &[], &[("MODULE_DESCR", 1)]);
-        f.change_file(lib, "mod foo;");
+fn module_descriptor(db: &impl ModulesDatabase, file_id: FileId) -> Arc<ModuleDescriptor> {
-        f.check_parent_modules(foo, &[lib], &[("MODULE_DESCR", 1)]);
+    let file = db.file_syntax(file_id);
+    Arc::new(ModuleDescriptor::new(file.ast()))
+}
-        f.remove_file(lib);
+fn module_tree(db: &impl ModulesDatabase, (): ()) -> Arc<ModuleTreeDescriptor> {
-        f.check_parent_modules(foo, &[], &[("MODULE_DESCR", 0)]);
+    let file_set = db.file_set(());
+    let mut files = Vec::new();
+    for &file_id in file_set.files.iter() {
+        let module_descr = db.module_descriptor(file_id);
+        files.push((file_id, module_descr));
    }
+    let res = ModuleTreeDescriptor::new(files.iter().map(|(file_id, descr)| (*file_id, &**descr)), &file_set.resolver);
+    Arc::new(res)
 }
diff --git a/crates/ra_analysis/src/queries.rs b/crates/ra_analysis/src/queries.rs
deleted file mode 100644
index 062a2f420..000000000
--- a/crates/ra_analysis/src/queries.rs
+++ /dev/null
@@ -1,39 +0,0 @@
-use std::sync::Arc;
-use ra_syntax::File;
-use ra_editor::LineIndex;
-use {
-    FileId,
-    db::{Query, QueryCtx, QueryRegistry},
-    symbol_index::SymbolIndex,
-};
-pub(crate) use db::{file_text, file_set};
-pub(crate) fn file_syntax(ctx: QueryCtx, file_id: FileId) -> File {
-    (&*ctx.get(FILE_SYNTAX, file_id)).clone()
-}
-pub(crate) fn file_lines(ctx: QueryCtx, file_id: FileId) -> Arc<LineIndex> {
-    ctx.get(FILE_LINES, file_id)
-}
-pub(crate) fn file_symbols(ctx: QueryCtx, file_id: FileId) -> Arc<SymbolIndex> {
-    ctx.get(FILE_SYMBOLS, file_id)
-}
-const FILE_SYNTAX: Query<FileId, File> = Query(16, |ctx, file_id: &FileId| {
-    let text = file_text(ctx, *file_id);
-    File::parse(&*text)
-});
-const FILE_LINES: Query<FileId, LineIndex> = Query(17, |ctx, file_id: &FileId| {
-    let text = file_text(ctx, *file_id);
-    LineIndex::new(&*text)
-});
-const FILE_SYMBOLS: Query<FileId, SymbolIndex> = Query(18, |ctx, file_id: &FileId| {
-    let syntax = file_syntax(ctx, *file_id);
-    SymbolIndex::for_file(*file_id, syntax)
-});
-pub(crate) fn register_queries(reg: &mut QueryRegistry) {
-    reg.add(FILE_SYNTAX, "FILE_SYNTAX");
-    reg.add(FILE_LINES, "FILE_LINES");
-    reg.add(FILE_SYMBOLS, "FILE_SYMBOLS");
-}
diff --git a/crates/ra_analysis/src/roots.rs b/crates/ra_analysis/src/roots.rs
index 32a8c5bd0..76bcecd38 100644
--- a/crates/ra_analysis/src/roots.rs
+++ b/crates/ra_analysis/src/roots.rs
@@ -5,16 +5,18 @@ use std::{
 use once_cell::sync::OnceCell;
 use rayon::prelude::*;
-use rustc_hash::FxHashMap;
+use salsa::Database;
+use rustc_hash::{FxHashMap, FxHashSet};
 use ra_editor::LineIndex;
 use ra_syntax::File;
-use {
+use crate::{
    FileId,
    imp::FileResolverImp,
    symbol_index::SymbolIndex,
    descriptors::{ModuleDescriptor, ModuleTreeDescriptor},
-    db::Db,
+    db::{self, FilesDatabase, SyntaxDatabase},
+    module_map::ModulesDatabase,
 };
 pub(crate) trait SourceRoot {
@@ -25,62 +27,68 @@ pub(crate) trait SourceRoot {
    fn symbols(&self, acc: &mut Vec<Arc<SymbolIndex>>);
 }
-#[derive(Default, Debug)]
+#[derive(Default, Debug, Clone)]
 pub(crate) struct WritableSourceRoot {
-    db: Db,
+    db: db::RootDatabase,
 }
 impl WritableSourceRoot {
    pub fn apply_changes(
-        &self,
+        &mut self,
        changes: &mut dyn Iterator<Item=(FileId, Option<String>)>,
        file_resolver: Option<FileResolverImp>,
-    ) -> WritableSourceRoot {
+    ) {
-        let resolver_changed = file_resolver.is_some();
+        let mut changed = FxHashSet::default();
-        let mut changed_files = Vec::new();
+        let mut removed = FxHashSet::default();
-        let mut new_state = self.db.state().clone();
        for (file_id, text) in changes {
-            changed_files.push(file_id);
            match text {
-                Some(text) => {
-                    new_state.file_map.insert(file_id, Arc::new(text));
-                },
                None => {
-                    new_state.file_map.remove(&file_id);
+                    removed.insert(file_id);
+                }
+                Some(text) => {
+                    self.db.query(db::FileTextQuery)
+                        .set(file_id, Arc::new(text));
+                    changed.insert(file_id);
                }
            }
        }
-        if let Some(file_resolver) = file_resolver {
+        let file_set = self.db.file_set(());
-            new_state.file_resolver = file_resolver
+        let mut files: FxHashSet<FileId> = file_set
-        }
+            .files
-        WritableSourceRoot {
+            .clone();
-            db: self.db.with_changes(new_state, &changed_files, resolver_changed)
+        for file_id in removed {
+            files.remove(&file_id);
        }
+        files.extend(changed);
+        let resolver = file_resolver.unwrap_or_else(|| file_set.resolver.clone());
+        self.db.query(db::FileSetQuery)
+            .set((), Arc::new(db::FileSet { files, resolver }));
    }
 }
 impl SourceRoot for WritableSourceRoot {
    fn module_tree(&self) -> Arc<ModuleTreeDescriptor> {
-        self.db.make_query(::module_map::module_tree)
+        self.db.module_tree(())
    }
    fn contains(&self, file_id: FileId) -> bool {
-        self.db.state().file_map.contains_key(&file_id)
+        self.db.file_set(())
+            .files
+            .contains(&file_id)
    }
    fn lines(&self, file_id: FileId) -> Arc<LineIndex> {
-        self.db.make_query(|ctx| ::queries::file_lines(ctx, file_id))
+        self.db.file_lines(file_id)
    }
    fn syntax(&self, file_id: FileId) -> File {
-        self.db.make_query(|ctx| ::queries::file_syntax(ctx, file_id))
+        self.db.file_syntax(file_id)
    }
    fn symbols<'a>(&'a self, acc: &mut Vec<Arc<SymbolIndex>>) {
-        self.db.make_query(|ctx| {
+        let db = &self.db;
-            let file_set = ::queries::file_set(ctx);
+        let symbols =  db.file_set(());
-            let syms = file_set.0.iter()
+        let symbols = symbols
-                .map(|file_id| ::queries::file_symbols(ctx, *file_id));
+            .files
-            acc.extend(syms);
+            .iter()
-        });
+            .map(|&file_id| db.file_symbols(file_id));
+        acc.extend(symbols);
    }
 }
diff --git a/crates/ra_analysis/src/symbol_index.rs b/crates/ra_analysis/src/symbol_index.rs
index ffbb6a29f..54672fde4 100644
--- a/crates/ra_analysis/src/symbol_index.rs
+++ b/crates/ra_analysis/src/symbol_index.rs
@@ -9,7 +9,7 @@ use ra_syntax::{
 };
 use fst::{self, Streamer};
 use rayon::prelude::*;
-use {Query, FileId, JobToken};
+use crate::{Query, FileId, JobToken};
 #[derive(Debug)]
 pub(crate) struct SymbolIndex {
@@ -17,6 +17,15 @@ pub(crate) struct SymbolIndex {
    map: fst::Map,
 }
+impl PartialEq for SymbolIndex {
+    fn eq(&self, other: &SymbolIndex) -> bool {
+        self.symbols == other.symbols
+    }
+}
+impl Eq for SymbolIndex {
+}
 impl Hash for SymbolIndex {
    fn hash<H: Hasher>(&self, hasher: &mut H) {
        self.symbols.hash(hasher)
diff --git a/crates/ra_analysis/tests/tests.rs b/crates/ra_analysis/tests/tests.rs
index a886cd0ff..2d3679fa9 100644
--- a/crates/ra_analysis/tests/tests.rs
+++ b/crates/ra_analysis/tests/tests.rs
@@ -1,6 +1,8 @@
 extern crate relative_path;
 extern crate ra_analysis;
 extern crate rustc_hash;
+extern crate ra_editor;
+extern crate ra_syntax;
 extern crate test_utils;
 use std::{
@@ -9,8 +11,8 @@ use std::{
 use rustc_hash::FxHashMap;
 use relative_path::{RelativePath, RelativePathBuf};
-use ra_analysis::{Analysis, AnalysisHost, FileId, FileResolver, JobHandle, CrateGraph, CrateId};
+use ra_analysis::{Analysis, AnalysisHost, FileId, FileResolver, JobHandle, CrateGraph, CrateId, FnDescriptor};
-use test_utils::assert_eq_dbg;
+use test_utils::{assert_eq_dbg, extract_offset};
 #[derive(Debug)]
 struct FileMap(Vec<(FileId, RelativePathBuf)>);
@@ -39,7 +41,7 @@ impl FileResolver for FileMap {
    }
 }
-fn analysis_host(files: &'static [(&'static str, &'static str)]) -> AnalysisHost {
+fn analysis_host(files: &[(&str, &str)]) -> AnalysisHost {
    let mut host = AnalysisHost::new();
    let mut file_map = Vec::new();
    for (id, &(path, contents)) in files.iter().enumerate() {
@@ -53,10 +55,20 @@ fn analysis_host(files: &'static [(&'static str, &'static str)]) -> AnalysisHost
    host
 }
-fn analysis(files: &'static [(&'static str, &'static str)]) -> Analysis {
+fn analysis(files: &[(&str, &str)]) -> Analysis {
    analysis_host(files).analysis()
 }
+fn get_signature(text: &str) -> (FnDescriptor, Option<usize>) {
+    let (offset, code) = extract_offset(text);
+    let code = code.as_str();
+    let (_handle, token) = JobHandle::new();
+    let snap = analysis(&[("/lib.rs", code)]);
+    snap.resolve_callable(FileId(1), offset, &token).unwrap()
+}
 #[test]
 fn test_resolve_module() {
    let snap = analysis(&[
@@ -145,3 +157,85 @@ fn test_resolve_crate_root() {
        vec![CrateId(1)],
    );
 }
+#[test]
+fn test_fn_signature_two_args_first() {
+    let (desc, param) = get_signature(
+r#"fn foo(x: u32, y: u32) -> u32 {x + y}
+fn bar() { foo(<|>3, ); }"#);
+    assert_eq!(desc.name, "foo".to_string());
+    assert_eq!(desc.params, vec!("x".to_string(),"y".to_string()));
+    assert_eq!(desc.ret_type, Some("-> u32".into()));
+    assert_eq!(param, Some(0));
+}
+#[test]
+fn test_fn_signature_two_args_second() {
+    let (desc, param) = get_signature(
+        r#"fn foo(x: u32, y: u32) -> u32 {x + y}
+fn bar() { foo(3, <|>); }"#);
+    assert_eq!(desc.name, "foo".to_string());
+    assert_eq!(desc.params, vec!("x".to_string(),"y".to_string()));
+    assert_eq!(desc.ret_type, Some("-> u32".into()));
+    assert_eq!(param, Some(1));
+}
+#[test]
+fn test_fn_signature_for_impl() {
+    let (desc, param) = get_signature(
+r#"struct F; impl F { pub fn new() { F{}} }
+fn bar() {let _ : F = F::new(<|>);}"#);
+    assert_eq!(desc.name, "new".to_string());
+    assert_eq!(desc.params, Vec::<String>::new());
+    assert_eq!(desc.ret_type, None);
+    assert_eq!(param, None);
+}
+#[test]
+fn test_fn_signature_for_method_self() {
+    let (desc, param) = get_signature(
+r#"struct F;
+impl F {
+    pub fn new() -> F{
+        F{}
+    }
+    pub fn do_it(&self) {}
+}
+fn bar() {
+    let f : F = F::new();
+    f.do_it(<|>);
+}"#);
+    assert_eq!(desc.name, "do_it".to_string());
+    assert_eq!(desc.params, vec!["&self".to_string()]);
+    assert_eq!(desc.ret_type, None);
+    assert_eq!(param, None);
+}
+#[test]
+fn test_fn_signature_for_method_with_arg() {
+    let (desc, param) = get_signature(
+r#"struct F;
+impl F {
+    pub fn new() -> F{
+        F{}
+    }
+    pub fn do_it(&self, x: i32) {}
+}
+fn bar() {
+    let f : F = F::new();
+    f.do_it(<|>);
+}"#);
+    assert_eq!(desc.name, "do_it".to_string());
+    assert_eq!(desc.params, vec!["&self".to_string(), "x".to_string()]);
+    assert_eq!(desc.ret_type, None);
+    assert_eq!(param, Some(1));
+}
diff --git a/crates/ra_cli/Cargo.toml b/crates/ra_cli/Cargo.toml
index 5e7bf3ed4..0b8d6f3dd 100644
--- a/crates/ra_cli/Cargo.toml
+++ b/crates/ra_cli/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "ra_cli"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
diff --git a/crates/ra_editor/Cargo.toml b/crates/ra_editor/Cargo.toml
index 91cefc8d7..7791da156 100644
--- a/crates/ra_editor/Cargo.toml
+++ b/crates/ra_editor/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "ra_editor"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
diff --git a/crates/ra_editor/src/code_actions.rs b/crates/ra_editor/src/code_actions.rs
index 216d592ff..7b0a48c81 100644
--- a/crates/ra_editor/src/code_actions.rs
+++ b/crates/ra_editor/src/code_actions.rs
@@ -11,7 +11,7 @@ use ra_syntax::{
    },
 };
-use {EditBuilder, Edit, find_node_at_offset};
+use crate::{EditBuilder, Edit, find_node_at_offset};
 #[derive(Debug)]
 pub struct LocalEdit {
@@ -136,7 +136,7 @@ fn non_trivia_sibling(node: SyntaxNodeRef, direction: Direction) -> Option<Synta
 #[cfg(test)]
 mod tests {
    use super::*;
-    use test_utils::{check_action, check_action_range};
+    use crate::test_utils::{check_action, check_action_range};
    #[test]
    fn test_swap_comma() {
diff --git a/crates/ra_editor/src/completion.rs b/crates/ra_editor/src/completion.rs
index 20b8484b3..b6095dca9 100644
--- a/crates/ra_editor/src/completion.rs
+++ b/crates/ra_editor/src/completion.rs
@@ -9,7 +9,7 @@ use ra_syntax::{
    text_utils::is_subrange,
 };
-use {
+use crate::{
    AtomEdit, find_node_at_offset,
    scope::{FnScopes, ModuleScope},
 };
diff --git a/crates/ra_editor/src/edit.rs b/crates/ra_editor/src/edit.rs
index 2839ac20a..46e687319 100644
--- a/crates/ra_editor/src/edit.rs
+++ b/crates/ra_editor/src/edit.rs
@@ -1,4 +1,4 @@
-use {TextRange, TextUnit};
+use crate::{TextRange, TextUnit};
 use ra_syntax::{
    AtomEdit,
    text_utils::contains_offset_nonstrict,
diff --git a/crates/ra_editor/src/folding_ranges.rs b/crates/ra_editor/src/folding_ranges.rs
index 3aabd54ae..a1699d449 100644
--- a/crates/ra_editor/src/folding_ranges.rs
+++ b/crates/ra_editor/src/folding_ranges.rs
@@ -1,8 +1,10 @@
 use rustc_hash::FxHashSet;
 use ra_syntax::{
+    ast,
+    AstNode,
    File, TextRange, SyntaxNodeRef,
-    SyntaxKind,
+    SyntaxKind::{self, *},
    Direction,
 };
@@ -20,67 +22,97 @@ pub struct Fold {
 pub fn folding_ranges(file: &File) -> Vec<Fold> {
    let mut res = vec![];
-    let mut visited = FxHashSet::default();
+    let mut visited_comments = FxHashSet::default();
    for node in file.syntax().descendants() {
-        if visited.contains(&node) {
+        // Fold items that span multiple lines
+        if let Some(kind) = fold_kind(node.kind()) {
+            if has_newline(node) {
+                res.push(Fold { range: node.range(), kind });
+            }
+        }
+        // Also fold groups of comments
+        if visited_comments.contains(&node) {
            continue;
        }
+        if node.kind() == COMMENT {
+            contiguous_range_for_comment(node, &mut visited_comments)
+                .map(|range| res.push(Fold { range, kind: FoldKind::Comment }));
+        }
+    }
+    res
+}
-        let range_and_kind = match node.kind() {
+fn fold_kind(kind: SyntaxKind) -> Option<FoldKind> {
-            SyntaxKind::COMMENT => (
+    match kind {
-                contiguous_range_for(SyntaxKind::COMMENT, node, &mut visited),
+        COMMENT => Some(FoldKind::Comment),
-                Some(FoldKind::Comment),
+        USE_ITEM => Some(FoldKind::Imports),
-            ),
+        _ => None
-            SyntaxKind::USE_ITEM => (
+    }
-                contiguous_range_for(SyntaxKind::USE_ITEM, node, &mut visited),
+}
-                Some(FoldKind::Imports),
-            ),
+fn has_newline(
-            _ => (None, None),
+    node: SyntaxNodeRef,
-        };
+) -> bool {
+    for descendant in node.descendants() {
-        match range_and_kind {
+        if let Some(ws) = ast::Whitespace::cast(descendant) {
-            (Some(range), Some(kind)) => {
+            if ws.has_newlines() {
-                res.push(Fold {
+                return true;
-                    range: range,
+            }
-                    kind: kind
+        } else if let Some(comment) = ast::Comment::cast(descendant) {
-                });
+            if comment.has_newlines() {
+                return true;
            }
-            _ => {}
        }
    }
-    res
+    false
 }
-fn contiguous_range_for<'a>(
+fn contiguous_range_for_comment<'a>(
-    kind: SyntaxKind,
+    first: SyntaxNodeRef<'a>,
-    node: SyntaxNodeRef<'a>,
    visited: &mut FxHashSet<SyntaxNodeRef<'a>>,
 ) -> Option<TextRange> {
-    visited.insert(node);
+    visited.insert(first);
-    let left = node;
+    // Only fold comments of the same flavor
-    let mut right = node;
+    let group_flavor = ast::Comment::cast(first)?.flavor();
-    for node in node.siblings(Direction::Next) {
-        visited.insert(node);
+    let mut last = first;
-        match node.kind() {
+    for node in first.siblings(Direction::Next) {
-            SyntaxKind::WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
+        if let Some(ws) = ast::Whitespace::cast(node) {
-            k => {
+            // There is a blank line, which means the group ends here
-                if k == kind {
+            if ws.count_newlines_lazy().take(2).count() == 2 {
-                    right = node
+                break;
-                } else {
+            }
-                    break;
-                }
+            // Ignore whitespace without blank lines
+            continue;
+        }
+        match ast::Comment::cast(node) {
+            Some(next_comment) if next_comment.flavor() == group_flavor => {
+                visited.insert(node);
+                last = node;
+            }
+            // The comment group ends because either:
+            // * An element of a different kind was reached
+            // * A comment of a different flavor was reached
+            _ => {
+                break
            }
        }
    }
-    if left != right {
+    if first != last {
        Some(TextRange::from_to(
-            left.range().start(),
+            first.range().start(),
-            right.range().end(),
+            last.range().end(),
        ))
    } else {
+        // The group consists of only one element, therefore it cannot be folded
        None
    }
 }
@@ -88,52 +120,65 @@ fn contiguous_range_for<'a>(
 #[cfg(test)]
 mod tests {
    use super::*;
+    use test_utils::extract_ranges;
+    fn do_check(text: &str, fold_kinds: &[FoldKind]) {
+        let (ranges, text) = extract_ranges(text);
+        let file = File::parse(&text);
+        let folds = folding_ranges(&file);
+        assert_eq!(folds.len(), ranges.len());
+        for ((fold, range), fold_kind) in folds.into_iter().zip(ranges.into_iter()).zip(fold_kinds.into_iter()) {
+            assert_eq!(fold.range.start(), range.start());
+            assert_eq!(fold.range.end(), range.end());
+            assert_eq!(&fold.kind, fold_kind);
+        }
+    }
    #[test]
    fn test_fold_comments() {
        let text = r#"
-// Hello
+<|>// Hello
 // this is a multiline
 // comment
-//
+//<|>
 // But this is not
 fn main() {
-    // We should
+    <|>// We should
    // also
    // fold
-    // this one.
+    // this one.<|>
+    <|>//! But this one is different
+    //! because it has another flavor<|>
+    <|>/* As does this
+    multiline comment */<|>
 }"#;
-        let file = File::parse(&text);
+        let fold_kinds = &[
-        let folds = folding_ranges(&file);
+            FoldKind::Comment,
-        assert_eq!(folds.len(), 2);
+            FoldKind::Comment,
-        assert_eq!(folds[0].range.start(), 1.into());
+            FoldKind::Comment,
-        assert_eq!(folds[0].range.end(), 46.into());
+            FoldKind::Comment,
-        assert_eq!(folds[0].kind, FoldKind::Comment);
+        ];
+        do_check(text, fold_kinds);
-        assert_eq!(folds[1].range.start(), 84.into());
-        assert_eq!(folds[1].range.end(), 137.into());
-        assert_eq!(folds[1].kind, FoldKind::Comment);
    }
    #[test]
    fn test_fold_imports() {
        let text = r#"
-use std::str;
+<|>use std::{
-use std::vec;
+    str,
-use std::io as iop;
+    vec,
+    io as iop
+};<|>
 fn main() {
 }"#;
-        let file = File::parse(&text);
+        let folds = &[FoldKind::Imports];
-        let folds = folding_ranges(&file);
+        do_check(text, folds);
-        assert_eq!(folds.len(), 1);
-        assert_eq!(folds[0].range.start(), 1.into());
-        assert_eq!(folds[0].range.end(), 48.into());
-        assert_eq!(folds[0].kind, FoldKind::Imports);
    }
diff --git a/crates/ra_editor/src/lib.rs b/crates/ra_editor/src/lib.rs
index 710afc65d..bd61fd191 100644
--- a/crates/ra_editor/src/lib.rs
+++ b/crates/ra_editor/src/lib.rs
@@ -164,7 +164,7 @@ pub fn resolve_local_name(file: &File, offset: TextUnit, name_ref: ast::NameRef)
 #[cfg(test)]
 mod tests {
    use super::*;
-    use test_utils::{assert_eq_dbg, extract_offset, add_cursor};
+    use crate::test_utils::{assert_eq_dbg, extract_offset, add_cursor};
    #[test]
    fn test_highlighting() {
diff --git a/crates/ra_editor/src/line_index.rs b/crates/ra_editor/src/line_index.rs
index 9cd8da3a8..95d64b8a8 100644
--- a/crates/ra_editor/src/line_index.rs
+++ b/crates/ra_editor/src/line_index.rs
@@ -1,7 +1,7 @@
 use superslice::Ext;
-use ::TextUnit;
+use crate::TextUnit;
-#[derive(Clone, Debug, Hash)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct LineIndex {
    newlines: Vec<TextUnit>,
 }
diff --git a/crates/ra_editor/src/scope/fn_scope.rs b/crates/ra_editor/src/scope/fn_scope.rs
index 9a48bda02..99d698b60 100644
--- a/crates/ra_editor/src/scope/fn_scope.rs
+++ b/crates/ra_editor/src/scope/fn_scope.rs
@@ -174,7 +174,7 @@ fn compute_expr_scopes(expr: ast::Expr, scopes: &mut FnScopes, scope: ScopeId) {
            }
        }
        ast::Expr::LambdaExpr(e) => {
-            let mut scope = scopes.new_scope(scope);
+            let scope = scopes.new_scope(scope);
            scopes.add_params_bindings(scope, e.param_list());
            if let Some(body) = e.body() {
                scopes.set_scope(body.syntax(), scope);
@@ -256,7 +256,7 @@ pub fn resolve_local_name<'a>(name_ref: ast::NameRef, scopes: &'a FnScopes) -> O
 mod tests {
    use super::*;
    use ra_syntax::File;
-    use {find_node_at_offset, test_utils::extract_offset};
+    use crate::{find_node_at_offset, test_utils::extract_offset};
    fn do_check(code: &str, expected: &[&str]) {
        let (off, code) = extract_offset(code);
diff --git a/crates/ra_editor/src/symbols.rs b/crates/ra_editor/src/symbols.rs
index e5cc5ca28..d9e4b2df7 100644
--- a/crates/ra_editor/src/symbols.rs
+++ b/crates/ra_editor/src/symbols.rs
@@ -6,7 +6,7 @@ use ra_syntax::{
        walk::{walk, WalkEvent},
    },
 };
-use TextRange;
+use crate::TextRange;
 #[derive(Debug, Clone)]
 pub struct StructureNode {
@@ -17,7 +17,7 @@ pub struct StructureNode {
    pub kind: SyntaxKind,
 }
-#[derive(Debug, Clone, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct FileSymbol {
    pub name: SmolStr,
    pub node_range: TextRange,
diff --git a/crates/ra_editor/src/test_utils.rs b/crates/ra_editor/src/test_utils.rs
index c4ea4db6c..49eb530d5 100644
--- a/crates/ra_editor/src/test_utils.rs
+++ b/crates/ra_editor/src/test_utils.rs
@@ -1,6 +1,6 @@
 use ra_syntax::{File, TextUnit, TextRange};
-pub use _test_utils::*;
+pub use crate::_test_utils::*;
-use LocalEdit;
+use crate::LocalEdit;
 pub fn check_action<F: Fn(&File, TextUnit) -> Option<LocalEdit>> (
    before: &str,
diff --git a/crates/ra_editor/src/typing.rs b/crates/ra_editor/src/typing.rs
index 1dc658f9b..542b9e10b 100644
--- a/crates/ra_editor/src/typing.rs
+++ b/crates/ra_editor/src/typing.rs
@@ -10,7 +10,7 @@ use ra_syntax::{
    SyntaxKind::*,
 };
-use {LocalEdit, EditBuilder, find_node_at_offset};
+use crate::{LocalEdit, EditBuilder, find_node_at_offset};
 pub fn join_lines(file: &File, range: TextRange) -> LocalEdit {
    let range = if range.is_empty() {
@@ -244,7 +244,7 @@ fn compute_ws(left: SyntaxNodeRef, right: SyntaxNodeRef) -> &'static str {
 #[cfg(test)]
 mod tests {
    use super::*;
-    use test_utils::{check_action, extract_range, extract_offset, add_cursor};
+    use crate::test_utils::{check_action, extract_range, extract_offset, add_cursor};
    fn check_join_lines(before: &str, after: &str) {
        check_action(before, after, |file, offset| {
diff --git a/crates/ra_lsp_server/Cargo.toml b/crates/ra_lsp_server/Cargo.toml
index 1fe6b2ebe..2b3257117 100644
--- a/crates/ra_lsp_server/Cargo.toml
+++ b/crates/ra_lsp_server/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "ra_lsp_server"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
diff --git a/crates/ra_lsp_server/src/caps.rs b/crates/ra_lsp_server/src/caps.rs
index 3c628f29c..5598ec75f 100644
--- a/crates/ra_lsp_server/src/caps.rs
+++ b/crates/ra_lsp_server/src/caps.rs
@@ -7,6 +7,7 @@ use languageserver_types::{
    TextDocumentSyncKind,
    ExecuteCommandOptions,
    CompletionOptions,
+    SignatureHelpOptions,
    DocumentOnTypeFormattingOptions,
 };
@@ -26,7 +27,9 @@ pub fn server_capabilities() -> ServerCapabilities {
            resolve_provider: None,
            trigger_characters: None,
        }),
-        signature_help_provider: None,
+        signature_help_provider: Some(SignatureHelpOptions {
+            trigger_characters: Some(vec!["(".to_string(), ",".to_string()])
+        }),
        definition_provider: Some(true),
        type_definition_provider: None,
        implementation_provider: None,
diff --git a/crates/ra_lsp_server/src/conv.rs b/crates/ra_lsp_server/src/conv.rs
index 08a656569..a75b160c5 100644
--- a/crates/ra_lsp_server/src/conv.rs
+++ b/crates/ra_lsp_server/src/conv.rs
@@ -7,7 +7,7 @@ use ra_editor::{LineIndex, LineCol, Edit, AtomEdit};
 use ra_syntax::{SyntaxKind, TextUnit, TextRange};
 use ra_analysis::{FileId, SourceChange, SourceFileEdit, FileSystemEdit};
-use {
+use crate::{
    Result,
    server_world::ServerWorld,
    req,
@@ -299,7 +299,7 @@ pub fn to_location(
        Ok(loc)
 }
-pub trait MapConvWith<'a>: Sized {
+pub trait MapConvWith<'a>: Sized + 'a {
    type Ctx;
    type Output;
@@ -309,7 +309,7 @@ pub trait MapConvWith<'a>: Sized {
 }
 impl<'a, I> MapConvWith<'a> for I
-    where I: Iterator,
+    where I: Iterator + 'a,
          I::Item: ConvWith
 {
    type Ctx = <I::Item as ConvWith>::Ctx;
diff --git a/crates/ra_lsp_server/src/lib.rs b/crates/ra_lsp_server/src/lib.rs
index 60652d55e..7224b1476 100644
--- a/crates/ra_lsp_server/src/lib.rs
+++ b/crates/ra_lsp_server/src/lib.rs
@@ -34,5 +34,7 @@ mod project_model;
 pub mod thread_watcher;
 pub type Result<T> = ::std::result::Result<T, ::failure::Error>;
-pub use caps::server_capabilities;
+pub use crate::{
-pub use main_loop::main_loop;
+    main_loop::main_loop,
+    caps::server_capabilities,
+};
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index ab8be15e9..5acb39b60 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -13,7 +13,7 @@ use ra_syntax::{
    text_utils::contains_offset_nonstrict
 };
-use ::{
+use crate::{
    req::{self, Decoration}, Result,
    conv::{Conv, ConvWith, TryConvWith, MapConvWith, to_location},
    server_world::ServerWorld,
@@ -411,6 +411,42 @@ pub fn handle_folding_range(
    Ok(res)
 }
+pub fn handle_signature_help(
+    world: ServerWorld,
+    params: req::TextDocumentPositionParams,
+    token: JobToken,
+) -> Result<Option<req::SignatureHelp>> {
+    use languageserver_types::{ParameterInformation, SignatureInformation};
+    let file_id = params.text_document.try_conv_with(&world)?;
+    let line_index = world.analysis().file_line_index(file_id);
+    let offset = params.position.conv_with(&line_index);
+    if let Some((descriptor, active_param)) = world.analysis().resolve_callable(file_id, offset, &token) {
+        let parameters : Vec<ParameterInformation> =
+            descriptor.params.iter().map(|param|
+                ParameterInformation {
+                    label: param.clone(),
+                    documentation: None
+                }
+            ).collect();
+        let sig_info = SignatureInformation {
+            label: descriptor.label,
+            documentation: None,
+            parameters: Some(parameters)
+        };
+        Ok(Some(req::SignatureHelp {
+            signatures: vec![sig_info],
+            active_signature: Some(0),
+            active_parameter: active_param.map(|a| a as u64)
+        }))
+    } else {
+        Ok(None)
+    }
+}
 pub fn handle_code_action(
    world: ServerWorld,
    params: req::CodeActionParams,
@@ -442,7 +478,7 @@ pub fn handle_code_action(
 }
 pub fn publish_diagnostics(
-    world: ServerWorld,
+    world: &ServerWorld,
    file_id: FileId,
 ) -> Result<req::PublishDiagnosticsParams> {
    let uri = world.file_id_to_uri(file_id)?;
@@ -461,7 +497,7 @@ pub fn publish_diagnostics(
 }
 pub fn publish_decorations(
-    world: ServerWorld,
+    world: &ServerWorld,
    file_id: FileId,
 ) -> Result<req::PublishDecorationsParams> {
    let uri = world.file_id_to_uri(file_id)?;
diff --git a/crates/ra_lsp_server/src/main_loop/mod.rs b/crates/ra_lsp_server/src/main_loop/mod.rs
index 402615e42..cf2477cb5 100644
--- a/crates/ra_lsp_server/src/main_loop/mod.rs
+++ b/crates/ra_lsp_server/src/main_loop/mod.rs
@@ -16,7 +16,7 @@ use gen_lsp_server::{
 };
 use rustc_hash::FxHashMap;
-use {
+use crate::{
    req,
    Result,
    vfs::{self, FileEvent},
@@ -255,6 +255,7 @@ fn on_request(
        .on::<req::Completion>(handlers::handle_completion)?
        .on::<req::CodeActionRequest>(handlers::handle_code_action)?
        .on::<req::FoldingRangeRequest>(handlers::handle_folding_range)?
+        .on::<req::SignatureHelpRequest>(handlers::handle_signature_help)?
        .finish();
    match req {
        Ok((id, handle)) => {
@@ -390,7 +391,7 @@ fn update_file_notifications_on_threadpool(
 ) {
    pool.spawn(move || {
        for file_id in subscriptions {
-            match handlers::publish_diagnostics(world.clone(), file_id) {
+            match handlers::publish_diagnostics(&world, file_id) {
                Err(e) => {
                    error!("failed to compute diagnostics: {:?}", e)
                }
@@ -399,7 +400,7 @@ fn update_file_notifications_on_threadpool(
                    sender.send(Task::Notify(not));
                }
            }
-            match handlers::publish_decorations(world.clone(), file_id) {
+            match handlers::publish_decorations(&world, file_id) {
                Err(e) => {
                    error!("failed to compute decorations: {:?}", e)
                }
diff --git a/crates/ra_lsp_server/src/project_model.rs b/crates/ra_lsp_server/src/project_model.rs
index 43e4fd654..c144d9596 100644
--- a/crates/ra_lsp_server/src/project_model.rs
+++ b/crates/ra_lsp_server/src/project_model.rs
@@ -5,7 +5,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use cargo_metadata::{metadata_run, CargoOpt};
 use ra_syntax::SmolStr;
-use {
+use crate::{
    Result,
    thread_watcher::{Worker, ThreadWatcher},
 };
diff --git a/crates/ra_lsp_server/src/req.rs b/crates/ra_lsp_server/src/req.rs
index f80957589..1630edf7f 100644
--- a/crates/ra_lsp_server/src/req.rs
+++ b/crates/ra_lsp_server/src/req.rs
@@ -14,6 +14,7 @@ pub use languageserver_types::{
    CompletionParams, CompletionResponse,
    DocumentOnTypeFormattingParams,
    TextDocumentEdit,
+    SignatureHelp, Hover
 };
 pub enum SyntaxTree {}
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index c4cdf83d4..9b3013ae8 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -8,7 +8,7 @@ use rustc_hash::FxHashMap;
 use languageserver_types::Url;
 use ra_analysis::{FileId, AnalysisHost, Analysis, CrateGraph, CrateId, LibraryData, FileResolver};
-use {
+use crate::{
    Result,
    path_map::{PathMap, Root},
    vfs::{FileEvent, FileEventKind},
@@ -23,7 +23,6 @@ pub struct ServerWorldState {
    pub mem_map: FxHashMap<FileId, Option<String>>,
 }
-#[derive(Clone)]
 pub struct ServerWorld {
    pub workspaces: Arc<Vec<CargoWorkspace>>,
    pub analysis: Analysis,
diff --git a/crates/ra_lsp_server/src/thread_watcher.rs b/crates/ra_lsp_server/src/thread_watcher.rs
index 86a3a91e0..3257effcb 100644
--- a/crates/ra_lsp_server/src/thread_watcher.rs
+++ b/crates/ra_lsp_server/src/thread_watcher.rs
@@ -1,7 +1,7 @@
 use std::thread;
 use crossbeam_channel::{bounded, unbounded, Sender, Receiver};
 use drop_bomb::DropBomb;
-use Result;
+use crate::Result;
 pub struct Worker<I, O> {
    pub inp: Sender<I>,
diff --git a/crates/ra_lsp_server/src/vfs.rs b/crates/ra_lsp_server/src/vfs.rs
index a1c1783f2..d8f9b1aac 100644
--- a/crates/ra_lsp_server/src/vfs.rs
+++ b/crates/ra_lsp_server/src/vfs.rs
@@ -5,7 +5,7 @@ use std::{
 use walkdir::WalkDir;
-use {
+use crate::{
    thread_watcher::{Worker, ThreadWatcher},
 };
diff --git a/crates/ra_lsp_server/tests/heavy_tests/main.rs b/crates/ra_lsp_server/tests/heavy_tests/main.rs
index dced45f55..7265b5999 100644
--- a/crates/ra_lsp_server/tests/heavy_tests/main.rs
+++ b/crates/ra_lsp_server/tests/heavy_tests/main.rs
@@ -12,7 +12,7 @@ mod support;
 use ra_lsp_server::req::{Runnables, RunnablesParams};
-use support::project;
+use crate::support::project;
 const LOG: &'static str = "";
diff --git a/crates/ra_lsp_server/tests/heavy_tests/support.rs b/crates/ra_lsp_server/tests/heavy_tests/support.rs
index 8fe2aa816..d1339f62f 100644
--- a/crates/ra_lsp_server/tests/heavy_tests/support.rs
+++ b/crates/ra_lsp_server/tests/heavy_tests/support.rs
@@ -25,7 +25,7 @@ use ra_lsp_server::{main_loop, req, thread_watcher::{ThreadWatcher, Worker}};
 pub fn project(fixture: &str) -> Server {
    static INIT: Once = Once::new();
-    INIT.call_once(|| Logger::with_env_or_str(::LOG).start().unwrap());
+    INIT.call_once(|| Logger::with_env_or_str(crate::LOG).start().unwrap());
    let tmp_dir = TempDir::new("test-project")
        .unwrap();
diff --git a/crates/ra_syntax/Cargo.toml b/crates/ra_syntax/Cargo.toml
index 6345e4725..34bb1c591 100644
--- a/crates/ra_syntax/Cargo.toml
+++ b/crates/ra_syntax/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "ra_syntax"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
diff --git a/crates/ra_syntax/src/algo/mod.rs b/crates/ra_syntax/src/algo/mod.rs
index a6678093d..e686a5704 100644
--- a/crates/ra_syntax/src/algo/mod.rs
+++ b/crates/ra_syntax/src/algo/mod.rs
@@ -1,7 +1,7 @@
 pub mod walk;
 pub mod visit;
-use {
+use crate::{
    SyntaxNodeRef, TextUnit, TextRange,
    text_utils::{contains_offset_nonstrict, is_subrange},
 };
diff --git a/crates/ra_syntax/src/algo/visit.rs b/crates/ra_syntax/src/algo/visit.rs
index 9f1c127c7..1ae988a87 100644
--- a/crates/ra_syntax/src/algo/visit.rs
+++ b/crates/ra_syntax/src/algo/visit.rs
@@ -1,5 +1,5 @@
 use std::marker::PhantomData;
-use {SyntaxNodeRef, AstNode};
+use crate::{SyntaxNodeRef, AstNode};
 pub fn visitor<'a, T>() -> impl Visitor<'a, Output=T> {
diff --git a/crates/ra_syntax/src/algo/walk.rs b/crates/ra_syntax/src/algo/walk.rs
index 8e294d965..d34415626 100644
--- a/crates/ra_syntax/src/algo/walk.rs
+++ b/crates/ra_syntax/src/algo/walk.rs
@@ -1,4 +1,4 @@
-use {
+use crate::{
    SyntaxNodeRef,
    algo::generate,
 };
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index ef7b5b1a1..160d186b8 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -1,7 +1,7 @@
 // This file is automatically generated based on the file `./generated.rs.tera` when `cargo gen-kinds` is run
 // Do not edit manually
-use {
+use crate::{
    ast,
    SyntaxNodeRef, AstNode,
    SyntaxKind::*,
@@ -1387,7 +1387,11 @@ impl<'a> AstNode<'a> for PathExpr<'a> {
    fn syntax(self) -> SyntaxNodeRef<'a> { self.syntax }
 }
-impl<'a> PathExpr<'a> {}
+impl<'a> PathExpr<'a> {
+    pub fn path(self) -> Option<Path<'a>> {
+        super::child_opt(self)
+    }
+}
 // PathPat
 #[derive(Debug, Clone, Copy)]
@@ -2193,3 +2197,21 @@ impl<'a> WhileExpr<'a> {
    }
 }
+// Whitespace
+#[derive(Debug, Clone, Copy)]
+pub struct Whitespace<'a> {
+    syntax: SyntaxNodeRef<'a>,
+}
+impl<'a> AstNode<'a> for Whitespace<'a> {
+    fn cast(syntax: SyntaxNodeRef<'a>) -> Option<Self> {
+        match syntax.kind() {
+            WHITESPACE => Some(Whitespace { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(self) -> SyntaxNodeRef<'a> { self.syntax }
+}
+impl<'a> Whitespace<'a> {}
diff --git a/crates/ra_syntax/src/ast/generated.rs.tera b/crates/ra_syntax/src/ast/generated.rs.tera
index ffa9c4134..5cb7a35ed 100644
--- a/crates/ra_syntax/src/ast/generated.rs.tera
+++ b/crates/ra_syntax/src/ast/generated.rs.tera
@@ -3,7 +3,7 @@ the below applies to the result of this template
 #}// This file is automatically generated based on the file `./generated.rs.tera` when `cargo gen-kinds` is run
 // Do not edit manually
-use {
+use crate::{
    ast,
    SyntaxNodeRef, AstNode,
    SyntaxKind::*,
diff --git a/crates/ra_syntax/src/ast/mod.rs b/crates/ra_syntax/src/ast/mod.rs
index 10dac72e5..88193a1ed 100644
--- a/crates/ra_syntax/src/ast/mod.rs
+++ b/crates/ra_syntax/src/ast/mod.rs
@@ -4,7 +4,7 @@ use std::marker::PhantomData;
 use itertools::Itertools;
-use {
+use crate::{
    SmolStr, SyntaxNodeRef, SyntaxKind::*,
    yellow::{RefRoot, SyntaxNodeChildren},
 };
@@ -100,8 +100,8 @@ impl<'a> Lifetime<'a> {
 }
 impl<'a> Comment<'a> {
-    pub fn text(&self) -> SmolStr {
+    pub fn text(&self) -> &SmolStr {
-        self.syntax().leaf_text().unwrap().clone()
+        self.syntax().leaf_text().unwrap()
    }
    pub fn flavor(&self) -> CommentFlavor {
@@ -120,9 +120,17 @@ impl<'a> Comment<'a> {
    pub fn prefix(&self) -> &'static str {
        self.flavor().prefix()
    }
+    pub fn count_newlines_lazy(&self) -> impl Iterator<Item = &()> {
+        self.text().chars().filter(|&c| c == '\n').map(|_| &())
+    }
+    pub fn has_newlines(&self) -> bool {
+        self.count_newlines_lazy().count() > 0
+    }
 }
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum CommentFlavor {
    Line,
    Doc,
@@ -142,6 +150,20 @@ impl CommentFlavor {
    }
 }
+impl<'a> Whitespace<'a> {
+    pub fn text(&self) -> &SmolStr {
+        &self.syntax().leaf_text().unwrap()
+    }
+    pub fn count_newlines_lazy(&self) -> impl Iterator<Item = &()> {
+        self.text().chars().filter(|&c| c == '\n').map(|_| &())
+    }
+    pub fn has_newlines(&self) -> bool {
+        self.count_newlines_lazy().count() > 0
+    }
+}
 impl<'a> Name<'a> {
    pub fn text(&self) -> SmolStr {
        let ident = self.syntax().first_child()
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 9da0c2c13..ea8063d3b 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -342,7 +342,7 @@ Grammar(
        "TupleExpr": (),
        "ArrayExpr": (),
        "ParenExpr": (),
-        "PathExpr": (),
+        "PathExpr": (options: ["Path"]),
        "LambdaExpr": (
            options: [
                "ParamList",
@@ -538,5 +538,6 @@ Grammar(
            options: [ "NameRef" ]
        ),
        "Comment": (),
+        "Whitespace": (),
    },
 )
diff --git a/crates/ra_syntax/src/grammar/expressions/atom.rs b/crates/ra_syntax/src/grammar/expressions/atom.rs
index a720d255f..e21de68c5 100644
--- a/crates/ra_syntax/src/grammar/expressions/atom.rs
+++ b/crates/ra_syntax/src/grammar/expressions/atom.rs
@@ -30,7 +30,7 @@ pub(super) const ATOM_EXPR_FIRST: TokenSet =
    token_set_union![
        LITERAL_FIRST,
        token_set![L_CURLY, L_PAREN, L_BRACK, PIPE, MOVE_KW, IF_KW, WHILE_KW, MATCH_KW, UNSAFE_KW,
-                   RETURN_KW, IDENT, SELF_KW, SUPER_KW, COLONCOLON, BREAK_KW, CONTINUE_KW, LIFETIME ],
+                   RETURN_KW, IDENT, SELF_KW, SUPER_KW, CRATE_KW, COLONCOLON, BREAK_KW, CONTINUE_KW, LIFETIME ],
    ];
 const EXPR_RECOVERY_SET: TokenSet =
diff --git a/crates/ra_syntax/src/grammar/mod.rs b/crates/ra_syntax/src/grammar/mod.rs
index 2cb11dc1e..1199ba230 100644
--- a/crates/ra_syntax/src/grammar/mod.rs
+++ b/crates/ra_syntax/src/grammar/mod.rs
@@ -31,7 +31,7 @@ mod type_args;
 mod type_params;
 mod types;
-use {
+use crate::{
    token_set::TokenSet,
    parser_api::{Marker, CompletedMarker, Parser},
    SyntaxKind::{self, *},
diff --git a/crates/ra_syntax/src/lexer/comments.rs b/crates/ra_syntax/src/lexer/comments.rs
index eb417c2dc..afe6886a1 100644
--- a/crates/ra_syntax/src/lexer/comments.rs
+++ b/crates/ra_syntax/src/lexer/comments.rs
@@ -1,6 +1,6 @@
-use lexer::ptr::Ptr;
+use crate::lexer::ptr::Ptr;
-use SyntaxKind::{self, *};
+use crate::SyntaxKind::{self, *};
 pub(crate) fn scan_shebang(ptr: &mut Ptr) -> bool {
    if ptr.at_str("!/") {
diff --git a/crates/ra_syntax/src/lexer/mod.rs b/crates/ra_syntax/src/lexer/mod.rs
index 3e11db88b..9dc0b63d6 100644
--- a/crates/ra_syntax/src/lexer/mod.rs
+++ b/crates/ra_syntax/src/lexer/mod.rs
@@ -4,7 +4,7 @@ mod numbers;
 mod ptr;
 mod strings;
-use {
+use crate::{
    SyntaxKind::{self, *},
    TextUnit,
 };
diff --git a/crates/ra_syntax/src/lexer/numbers.rs b/crates/ra_syntax/src/lexer/numbers.rs
index 22e7d4e99..46daf5e52 100644
--- a/crates/ra_syntax/src/lexer/numbers.rs
+++ b/crates/ra_syntax/src/lexer/numbers.rs
@@ -1,7 +1,7 @@
-use lexer::classes::*;
+use crate::lexer::classes::*;
-use lexer::ptr::Ptr;
+use crate::lexer::ptr::Ptr;
-use SyntaxKind::{self, *};
+use crate::SyntaxKind::{self, *};
 pub(crate) fn scan_number(c: char, ptr: &mut Ptr) -> SyntaxKind {
    if c == '0' {
diff --git a/crates/ra_syntax/src/lexer/ptr.rs b/crates/ra_syntax/src/lexer/ptr.rs
index c9a5354ea..c4708cb1c 100644
--- a/crates/ra_syntax/src/lexer/ptr.rs
+++ b/crates/ra_syntax/src/lexer/ptr.rs
@@ -1,4 +1,4 @@
-use TextUnit;
+use crate::TextUnit;
 use std::str::Chars;
diff --git a/crates/ra_syntax/src/lexer/strings.rs b/crates/ra_syntax/src/lexer/strings.rs
index 5ff483d14..bceacdcac 100644
--- a/crates/ra_syntax/src/lexer/strings.rs
+++ b/crates/ra_syntax/src/lexer/strings.rs
@@ -1,6 +1,6 @@
-use SyntaxKind::{self, *};
+use crate::SyntaxKind::{self, *};
-use lexer::ptr::Ptr;
+use crate::lexer::ptr::Ptr;
 pub(crate) fn is_string_literal_start(c: char, c1: Option<char>, c2: Option<char>) -> bool {
    match (c, c1, c2) {
diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index 703469629..7eba5ee61 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -46,7 +46,7 @@ mod yellow;
 pub mod utils;
 pub mod text_utils;
-pub use {
+pub use crate::{
    rowan::{SmolStr, TextRange, TextUnit},
    ast::AstNode,
    lexer::{tokenize, Token},
@@ -55,11 +55,11 @@ pub use {
    reparsing::AtomEdit,
 };
-use {
+use crate::{
    yellow::{GreenNode},
 };
-#[derive(Clone, Debug, Hash)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct File {
    root: SyntaxNode
 }
diff --git a/crates/ra_syntax/src/parser_api.rs b/crates/ra_syntax/src/parser_api.rs
index 772d753af..cc23bb75e 100644
--- a/crates/ra_syntax/src/parser_api.rs
+++ b/crates/ra_syntax/src/parser_api.rs
@@ -1,4 +1,4 @@
-use {
+use crate::{
    token_set::TokenSet,
    parser_impl::ParserImpl,
    SyntaxKind::{self, ERROR},
diff --git a/crates/ra_syntax/src/parser_impl/event.rs b/crates/ra_syntax/src/parser_impl/event.rs
index 95e5ce4cc..928d2cc7a 100644
--- a/crates/ra_syntax/src/parser_impl/event.rs
+++ b/crates/ra_syntax/src/parser_impl/event.rs
@@ -8,7 +8,7 @@
 //! `start node`, `finish node`, and `FileBuilder` converts
 //! this stream to a real tree.
 use std::mem;
-use {
+use crate::{
    TextUnit, TextRange, SmolStr,
    lexer::Token,
    parser_impl::Sink,
diff --git a/crates/ra_syntax/src/parser_impl/input.rs b/crates/ra_syntax/src/parser_impl/input.rs
index c0fe4d488..ac6d900d8 100644
--- a/crates/ra_syntax/src/parser_impl/input.rs
+++ b/crates/ra_syntax/src/parser_impl/input.rs
@@ -1,4 +1,4 @@
-use {lexer::Token, SyntaxKind, SyntaxKind::EOF, TextRange, TextUnit};
+use crate::{lexer::Token, SyntaxKind, SyntaxKind::EOF, TextRange, TextUnit};
 use std::ops::{Add, AddAssign};
diff --git a/crates/ra_syntax/src/parser_impl/mod.rs b/crates/ra_syntax/src/parser_impl/mod.rs
index 8d74cef0e..c2a6448e7 100644
--- a/crates/ra_syntax/src/parser_impl/mod.rs
+++ b/crates/ra_syntax/src/parser_impl/mod.rs
@@ -3,7 +3,7 @@ mod input;
 use std::cell::Cell;
-use {
+use crate::{
    TextUnit, SmolStr,
    lexer::Token,
    parser_api::Parser,
@@ -13,7 +13,7 @@ use {
    },
 };
-use SyntaxKind::{self, EOF, TOMBSTONE};
+use crate::SyntaxKind::{self, EOF, TOMBSTONE};
 pub(crate) trait Sink {
    type Tree;
diff --git a/crates/ra_syntax/src/reparsing.rs b/crates/ra_syntax/src/reparsing.rs
index d8b6a6a10..16272fe88 100644
--- a/crates/ra_syntax/src/reparsing.rs
+++ b/crates/ra_syntax/src/reparsing.rs
@@ -1,14 +1,14 @@
-use algo;
+use crate::algo;
-use grammar;
+use crate::grammar;
-use lexer::{tokenize, Token};
+use crate::lexer::{tokenize, Token};
-use yellow::{self, GreenNode, SyntaxNodeRef, SyntaxError};
+use crate::yellow::{self, GreenNode, SyntaxNodeRef, SyntaxError};
-use parser_impl;
+use crate::parser_impl;
-use parser_api::Parser;
+use crate::parser_api::Parser;
-use {
+use crate::{
    TextUnit, TextRange,
    SyntaxKind::*,
 };
-use text_utils::replace_range;
+use crate::text_utils::replace_range;
 #[derive(Debug, Clone)]
 pub struct AtomEdit {
diff --git a/crates/ra_syntax/src/syntax_kinds/mod.rs b/crates/ra_syntax/src/syntax_kinds/mod.rs
index 332cd13ac..3041e5633 100644
--- a/crates/ra_syntax/src/syntax_kinds/mod.rs
+++ b/crates/ra_syntax/src/syntax_kinds/mod.rs
@@ -1,7 +1,7 @@
 mod generated;
 use std::fmt;
-use SyntaxKind::*;
+use crate::SyntaxKind::*;
 pub use self::generated::SyntaxKind;
diff --git a/crates/ra_syntax/src/text_utils.rs b/crates/ra_syntax/src/text_utils.rs
index 58ae1e43e..adf26ef30 100644
--- a/crates/ra_syntax/src/text_utils.rs
+++ b/crates/ra_syntax/src/text_utils.rs
@@ -1,4 +1,4 @@
-use {TextRange, TextUnit};
+use crate::{TextRange, TextUnit};
 pub fn contains_offset_nonstrict(range: TextRange, offset: TextUnit) -> bool {
    range.start() <= offset && offset <= range.end()
diff --git a/crates/ra_syntax/src/token_set.rs b/crates/ra_syntax/src/token_set.rs
index c83fba81b..d407dfa48 100644
--- a/crates/ra_syntax/src/token_set.rs
+++ b/crates/ra_syntax/src/token_set.rs
@@ -1,4 +1,4 @@
-use SyntaxKind;
+use crate::SyntaxKind;
 #[derive(Clone, Copy)]
 pub(crate) struct TokenSet(pub(crate) u128);
@@ -29,7 +29,7 @@ macro_rules! token_set_union {
 #[test]
 fn token_set_works_for_tokens() {
-    use SyntaxKind::*;
+    use crate::SyntaxKind::*;
    let ts = token_set! { EOF, SHEBANG };
    assert!(ts.contains(EOF));
    assert!(ts.contains(SHEBANG));
diff --git a/crates/ra_syntax/src/utils.rs b/crates/ra_syntax/src/utils.rs
index e274f7471..df1f4b372 100644
--- a/crates/ra_syntax/src/utils.rs
+++ b/crates/ra_syntax/src/utils.rs
@@ -1,5 +1,5 @@
 use std::fmt::Write;
-use {
+use crate::{
    algo::walk::{walk, WalkEvent},
    SyntaxKind, File, SyntaxNodeRef
 };
diff --git a/crates/ra_syntax/src/yellow/builder.rs b/crates/ra_syntax/src/yellow/builder.rs
index c307b2bd0..67a1a382b 100644
--- a/crates/ra_syntax/src/yellow/builder.rs
+++ b/crates/ra_syntax/src/yellow/builder.rs
@@ -1,5 +1,5 @@
 use rowan::GreenNodeBuilder;
-use {
+use crate::{
    TextUnit, SmolStr,
    parser_impl::Sink,
    yellow::{GreenNode, SyntaxError, RaTypes},
diff --git a/crates/ra_syntax/src/yellow/mod.rs b/crates/ra_syntax/src/yellow/mod.rs
index 710320f47..ab9bca0f0 100644
--- a/crates/ra_syntax/src/yellow/mod.rs
+++ b/crates/ra_syntax/src/yellow/mod.rs
@@ -6,7 +6,7 @@ use std::{
    hash::{Hash, Hasher},
 };
 use rowan::Types;
-use {SyntaxKind, TextUnit, TextRange, SmolStr};
+use crate::{SyntaxKind, TextUnit, TextRange, SmolStr};
 use self::syntax_text::SyntaxText;
 pub use rowan::{TreeRoot};
@@ -70,16 +70,16 @@ impl<'a> SyntaxNodeRef<'a> {
        self.0.leaf_text()
    }
    pub fn ancestors(self) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
-        ::algo::generate(Some(self), |&node| node.parent())
+        crate::algo::generate(Some(self), |&node| node.parent())
    }
    pub fn descendants(self) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
-        ::algo::walk::walk(self).filter_map(|event| match event {
+        crate::algo::walk::walk(self).filter_map(|event| match event {
-            ::algo::walk::WalkEvent::Enter(node) => Some(node),
+            crate::algo::walk::WalkEvent::Enter(node) => Some(node),
-            ::algo::walk::WalkEvent::Exit(_) => None,
+            crate::algo::walk::WalkEvent::Exit(_) => None,
        })
    }
    pub fn siblings(self, direction: Direction) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
-        ::algo::generate(Some(self), move |&node| match direction {
+        crate::algo::generate(Some(self), move |&node| match direction {
            Direction::Next => node.next_sibling(),
            Direction::Prev => node.prev_sibling(),
        })
@@ -156,7 +156,7 @@ impl<R: TreeRoot<RaTypes>> Iterator for SyntaxNodeChildren<R> {
 fn has_short_text(kind: SyntaxKind) -> bool {
-    use SyntaxKind::*;
+    use crate::SyntaxKind::*;
    match kind {
        IDENT | LIFETIME | INT_NUMBER | FLOAT_NUMBER => true,
        _ => false,
diff --git a/crates/ra_syntax/src/yellow/syntax_text.rs b/crates/ra_syntax/src/yellow/syntax_text.rs
index 0db1049de..ae33b993d 100644
--- a/crates/ra_syntax/src/yellow/syntax_text.rs
+++ b/crates/ra_syntax/src/yellow/syntax_text.rs
@@ -2,7 +2,7 @@ use std::{
    fmt, ops,
 };
-use {
+use crate::{
    SyntaxNodeRef, TextRange, TextUnit,
    text_utils::{intersect, contains_offset_nonstrict},
 };
diff --git a/crates/ra_syntax/tests/data/parser/ok/0035_crate_path_in_call.rs b/crates/ra_syntax/tests/data/parser/ok/0035_crate_path_in_call.rs
new file mode 100644
index 000000000..f1ed30220
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/ok/0035_crate_path_in_call.rs
@@ -0,0 +1,3 @@
+fn main() {
+    make_query(crate::module_map::module_tree);
+}
diff --git a/crates/ra_syntax/tests/data/parser/ok/0035_crate_path_in_call.txt b/crates/ra_syntax/tests/data/parser/ok/0035_crate_path_in_call.txt
new file mode 100644
index 000000000..364315180
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/ok/0035_crate_path_in_call.txt
@@ -0,0 +1,41 @@
+ROOT@[0; 62)
+  FN_DEF@[0; 61)
+    FN_KW@[0; 2)
+    WHITESPACE@[2; 3)
+    NAME@[3; 7)
+      IDENT@[3; 7) "main"
+    PARAM_LIST@[7; 9)
+      L_PAREN@[7; 8)
+      R_PAREN@[8; 9)
+    WHITESPACE@[9; 10)
+    BLOCK@[10; 61)
+      L_CURLY@[10; 11)
+      WHITESPACE@[11; 16)
+      EXPR_STMT@[16; 59)
+        CALL_EXPR@[16; 58)
+          PATH_EXPR@[16; 26)
+            PATH@[16; 26)
+              PATH_SEGMENT@[16; 26)
+                NAME_REF@[16; 26)
+                  IDENT@[16; 26) "make_query"
+          ARG_LIST@[26; 58)
+            L_PAREN@[26; 27)
+            PATH_EXPR@[27; 57)
+              PATH@[27; 57)
+                PATH@[27; 44)
+                  PATH@[27; 32)
+                    PATH_SEGMENT@[27; 32)
+                      CRATE_KW@[27; 32)
+                  COLONCOLON@[32; 34)
+                  PATH_SEGMENT@[34; 44)
+                    NAME_REF@[34; 44)
+                      IDENT@[34; 44) "module_map"
+                COLONCOLON@[44; 46)
+                PATH_SEGMENT@[46; 57)
+                  NAME_REF@[46; 57)
+                    IDENT@[46; 57) "module_tree"
+            R_PAREN@[57; 58)
+        SEMI@[58; 59)
+      WHITESPACE@[59; 60)
+      R_CURLY@[60; 61)
+  WHITESPACE@[61; 62)
diff --git a/crates/salsa/Cargo.toml b/crates/salsa/Cargo.toml
deleted file mode 100644
index 9eb83234f..000000000
--- a/crates/salsa/Cargo.toml
+++ /dev/null
@@ -1,8 +0,0 @@
-[package]
-name = "salsa"
-version = "0.1.0"
-authors = ["Aleksey Kladov <[email protected]>"]
-[dependencies]
-parking_lot = "0.6.3"
-im = "12.0.0"
diff --git a/crates/salsa/src/lib.rs b/crates/salsa/src/lib.rs
deleted file mode 100644
index 35deed374..000000000
--- a/crates/salsa/src/lib.rs
+++ /dev/null
@@ -1,293 +0,0 @@
-extern crate im;
-extern crate parking_lot;
-use std::{
-    sync::Arc,
-    collections::{HashSet, HashMap},
-    cell::RefCell,
-};
-use parking_lot::Mutex;
-pub type GroundQueryFn<T, D> = Box<Fn(&T, &D) -> (D, OutputFingerprint) + Send + Sync + 'static>;
-pub type QueryFn<T, D> = Box<Fn(&QueryCtx<T, D>, &D) -> (D, OutputFingerprint) + Send + Sync + 'static>;
-#[derive(Debug)]
-pub struct Db<T, D> {
-    db: Arc<DbState<T, D>>,
-    query_config: Arc<QueryConfig<T, D>>,
-}
-pub struct QueryConfig<T, D> {
-    ground_fn: HashMap<QueryTypeId, GroundQueryFn<T, D>>,
-    query_fn: HashMap<QueryTypeId, QueryFn<T, D>>,
-}
-impl<T, D> ::std::fmt::Debug for QueryConfig<T, D> {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
-        ::std::fmt::Display::fmt("QueryConfig { ... }", f)
-    }
-}
-#[derive(Debug)]
-struct DbState<T, D> {
-    ground_data: T,
-    gen: Gen,
-    graph: Mutex<im::HashMap<QueryId, (Gen, Arc<QueryRecord<D>>)>>,
-}
-#[derive(Debug)]
-struct QueryRecord<D> {
-    params: D,
-    output: D,
-    output_fingerprint: OutputFingerprint,
-    deps: Vec<(QueryId, OutputFingerprint)>,
-}
-impl<T, D> DbState<T, D> {
-    fn record(
-        &self,
-        query_id: QueryId,
-        params: D,
-        output: D,
-        output_fingerprint: OutputFingerprint,
-        deps: Vec<(QueryId, OutputFingerprint)>,
-    ) {
-        let gen = self.gen;
-        let record = QueryRecord {
-            params,
-            output,
-            output_fingerprint,
-            deps,
-        };
-        self.graph.lock().insert(query_id, (gen, Arc::new(record)));
-    }
-}
-impl<T, D> QueryConfig<T, D> {
-    pub fn new() -> Self {
-        QueryConfig {
-            ground_fn: HashMap::new(),
-            query_fn: HashMap::new(),
-        }
-    }
-    pub fn with_ground_query(
-        mut self,
-        query_type: QueryTypeId,
-        query_fn: GroundQueryFn<T, D>
-    ) -> Self {
-        let prev = self.ground_fn.insert(query_type, query_fn);
-        assert!(prev.is_none());
-        self
-    }
-    pub fn with_query(
-        mut self,
-        query_type: QueryTypeId,
-        query_fn: QueryFn<T, D>,
-    ) -> Self {
-        let prev = self.query_fn.insert(query_type, query_fn);
-        assert!(prev.is_none());
-        self
-    }
-}
-pub struct QueryCtx<T, D> {
-    db: Arc<DbState<T, D>>,
-    query_config: Arc<QueryConfig<T, D>>,
-    stack: RefCell<Vec<Vec<(QueryId, OutputFingerprint)>>>,
-    executed: RefCell<Vec<QueryTypeId>>,
-}
-impl<T, D> QueryCtx<T, D>
-where
-    D: Clone
-{
-    fn new(db: &Db<T, D>) -> QueryCtx<T, D> {
-        QueryCtx {
-            db: Arc::clone(&db.db),
-            query_config: Arc::clone(&db.query_config),
-            stack: RefCell::new(vec![Vec::new()]),
-            executed: RefCell::new(Vec::new()),
-        }
-    }
-    pub fn get(
-        &self,
-        query_id: QueryId,
-        params: D,
-    ) -> D {
-        let (res, output_fingerprint) = self.get_inner(query_id, params);
-        self.record_dep(query_id, output_fingerprint);
-        res
-    }
-    pub fn trace(&self) -> Vec<QueryTypeId> {
-        ::std::mem::replace(&mut *self.executed.borrow_mut(), Vec::new())
-    }
-    fn get_inner(
-        &self,
-        query_id: QueryId,
-        params: D,
-    ) -> (D, OutputFingerprint) {
-        let (gen, record) = {
-            let guard = self.db.graph.lock();
-            match guard.get(&query_id).map(|it| it.clone()){
-                None => {
-                    drop(guard);
-                    return self.force(query_id, params);
-                },
-                Some(it) => it,
-            }
-        };
-        if gen == self.db.gen {
-            return (record.output.clone(), record.output_fingerprint)
-        }
-        if self.query_config.ground_fn.contains_key(&query_id.0) {
-            let (invalidated, record) = {
-                let guard = self.db.graph.lock();
-                let (gen, ref record) = guard[&query_id];
-                (gen == INVALIDATED, record.clone())
-            };
-            if invalidated {
-                return self.force(query_id, params);
-            } else {
-                return (record.output.clone(), record.output_fingerprint);
-            }
-        }
-        for (dep_query_id, prev_fingerprint) in record.deps.iter().cloned() {
-            let dep_params: D = {
-                let guard = self.db.graph.lock();
-                guard[&dep_query_id]
-                .1
-                .params
-                .clone()
-            };
-            if prev_fingerprint != self.get_inner(dep_query_id, dep_params).1 {
-                return self.force(query_id, params)
-            }
-        }
-        let gen = self.db.gen;
-        {
-            let mut guard = self.db.graph.lock();
-            guard[&query_id].0 = gen;
-        }
-        (record.output.clone(), record.output_fingerprint)
-    }
-    fn force(
-        &self,
-        query_id: QueryId,
-        params: D,
-    ) -> (D, OutputFingerprint) {
-        self.executed.borrow_mut().push(query_id.0);
-        self.stack.borrow_mut().push(Vec::new());
-        let (res, output_fingerprint) = if let Some(f) = self.query_config.ground_fn.get(&query_id.0) {
-            f(&self.db.ground_data, &params)
-        } else if let Some(f) = self.query_config.query_fn.get(&query_id.0) {
-            f(self, &params)
-        } else {
-            panic!("unknown query type: {:?}", query_id.0);
-        };
-        let res: D = res.into();
-        let deps = self.stack.borrow_mut().pop().unwrap();
-        self.db.record(query_id, params, res.clone(), output_fingerprint, deps);
-        (res, output_fingerprint)
-    }
-    fn record_dep(
-        &self,
-        query_id: QueryId,
-        output_fingerprint: OutputFingerprint,
-    ) -> () {
-        let mut stack = self.stack.borrow_mut();
-        let deps = stack.last_mut().unwrap();
-        deps.push((query_id, output_fingerprint))
-    }
-}
-pub struct Invalidations {
-    types: HashSet<QueryTypeId>,
-    ids: Vec<QueryId>,
-}
-impl Invalidations {
-    pub fn new() -> Invalidations {
-        Invalidations {
-            types: HashSet::new(),
-            ids: Vec::new(),
-        }
-    }
-    pub fn invalidate(
-        &mut self,
-        query_type: QueryTypeId,
-        params: impl Iterator<Item=InputFingerprint>,
-    ) {
-        self.types.insert(query_type);
-        self.ids.extend(params.map(|it| QueryId(query_type, it)))
-    }
-}
-impl<T, D> Db<T, D>
-where
-    D: Clone
-{
-    pub fn new(query_config: QueryConfig<T, D>, ground_data: T) -> Db<T, D> {
-        Db {
-            db: Arc::new(DbState { ground_data, gen: Gen(0), graph: Default::default() }),
-            query_config: Arc::new(query_config),
-        }
-    }
-    pub fn ground_data(&self) -> &T {
-        &self.db.ground_data
-    }
-    pub fn with_ground_data(
-        &self,
-        ground_data: T,
-        invalidations: Invalidations,
-    ) -> Db<T, D> {
-        for id in self.query_config.ground_fn.keys() {
-            assert!(
-                invalidations.types.contains(id),
-                "all ground queries must be invalidated"
-            );
-        }
-        let gen = Gen(self.db.gen.0 + 1);
-        let mut graph = self.db.graph.lock().clone();
-        for id in invalidations.ids {
-            if let Some((gen, _)) = graph.get_mut(&id) {
-                *gen = INVALIDATED;
-            }
-        }
-        let graph = Mutex::new(graph);
-        Db {
-            db: Arc::new(DbState { ground_data, gen, graph }),
-            query_config: Arc::clone(&self.query_config)
-        }
-    }
-    pub fn query_ctx(&self) -> QueryCtx<T, D> {
-        QueryCtx::new(self)
-    }
-    pub fn get(
-        &self,
-        query_id: QueryId,
-        params: D,
-    ) -> (D, Vec<QueryTypeId>) {
-        let ctx = self.query_ctx();
-        let res = ctx.get(query_id, params.into());
-        let executed = ::std::mem::replace(&mut *ctx.executed.borrow_mut(), Vec::new());
-        (res, executed)
-    }
-}
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-struct Gen(u64);
-const INVALIDATED: Gen = Gen(!0);
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct InputFingerprint(pub u64);
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct OutputFingerprint(pub u64);
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct QueryTypeId(pub u16);
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct QueryId(pub QueryTypeId, pub InputFingerprint);
diff --git a/crates/salsa/tests/integration.rs b/crates/salsa/tests/integration.rs
deleted file mode 100644
index aed9219be..000000000
--- a/crates/salsa/tests/integration.rs
+++ /dev/null
@@ -1,170 +0,0 @@
-extern crate salsa;
-use std::{
-    iter::once,
-    sync::Arc,
-    collections::hash_map::{HashMap, DefaultHasher},
-    any::Any,
-    hash::{Hash, Hasher},
-};
-type State = HashMap<u32, String>;
-type Data = Arc<Any + Send + Sync + 'static>;
-const GET_TEXT: salsa::QueryTypeId = salsa::QueryTypeId(1);
-const GET_FILES: salsa::QueryTypeId = salsa::QueryTypeId(2);
-const FILE_NEWLINES: salsa::QueryTypeId = salsa::QueryTypeId(3);
-const TOTAL_NEWLINES: salsa::QueryTypeId = salsa::QueryTypeId(4);
-fn mk_ground_query<T, R>(
-    state: &State,
-    params: &Data,
-    f: fn(&State, &T) -> R,
-) -> (Data, salsa::OutputFingerprint)
-where
-    T: 'static,
-    R: Hash + Send + Sync + 'static,
-{
-    let params = params.downcast_ref().unwrap();
-    let result = f(state, params);
-    let fingerprint = o_print(&result);
-    (Arc::new(result), fingerprint)
-}
-fn get<T, R>(db: &salsa::Db<State, Data>, query_type: salsa::QueryTypeId, param: T) -> (Arc<R>, Vec<salsa::QueryTypeId>)
-where
-    T: Hash + Send + Sync + 'static,
-    R: Send + Sync + 'static,
-{
-    let i_print = i_print(&param);
-    let param = Arc::new(param);
-    let (res, trace) = db.get(salsa::QueryId(query_type, i_print), param);
-    (res.downcast().unwrap(), trace)
-}
-struct QueryCtx<'a>(&'a salsa::QueryCtx<State, Data>);
-impl<'a> QueryCtx<'a> {
-    fn get_text(&self, id: u32) -> Arc<String> {
-        let i_print = i_print(&id);
-        let text = self.0.get(salsa::QueryId(GET_TEXT, i_print), Arc::new(id));
-        text.downcast().unwrap()
-    }
-    fn get_files(&self) -> Arc<Vec<u32>> {
-        let i_print = i_print(&());
-        let files = self.0.get(salsa::QueryId(GET_FILES, i_print), Arc::new(()));
-        let res = files.downcast().unwrap();
-        res
-    }
-    fn get_n_lines(&self, id: u32) -> usize {
-        let i_print = i_print(&id);
-        let n_lines = self.0.get(salsa::QueryId(FILE_NEWLINES, i_print), Arc::new(id));
-        *n_lines.downcast().unwrap()
-    }
-}
-fn mk_query<T, R>(
-    query_ctx: &salsa::QueryCtx<State, Data>,
-    params: &Data,
-    f: fn(QueryCtx, &T) -> R,
-) -> (Data, salsa::OutputFingerprint)
-where
-    T: 'static,
-    R: Hash + Send + Sync + 'static,
-{
-    let params: &T = params.downcast_ref().unwrap();
-    let query_ctx = QueryCtx(query_ctx);
-    let result = f(query_ctx, params);
-    let fingerprint = o_print(&result);
-    (Arc::new(result), fingerprint)
-}
-fn mk_queries() -> salsa::QueryConfig<State, Data> {
-    salsa::QueryConfig::<State, Data>::new()
-        .with_ground_query(GET_TEXT, Box::new(|state, id| {
-            mk_ground_query::<u32, String>(state, id, |state, id| state[id].clone())
-        }))
-        .with_ground_query(GET_FILES, Box::new(|state, id| {
-            mk_ground_query::<(), Vec<u32>>(state, id, |state, &()| state.keys().cloned().collect())
-        }))
-        .with_query(FILE_NEWLINES, Box::new(|query_ctx, id| {
-            mk_query(query_ctx, id, |query_ctx, &id| {
-                let text = query_ctx.get_text(id);
-                text.lines().count()
-            })
-        }))
-        .with_query(TOTAL_NEWLINES, Box::new(|query_ctx, id| {
-            mk_query(query_ctx, id, |query_ctx, &()| {
-                let mut total = 0;
-                for &id in query_ctx.get_files().iter() {
-                    total += query_ctx.get_n_lines(id)
-                }
-                total
-            })
-        }))
-}
-#[test]
-fn test_number_of_lines() {
-    let mut state = State::new();
-    let db = salsa::Db::new(mk_queries(), state.clone());
-    let (newlines, trace) = get::<(), usize>(&db, TOTAL_NEWLINES, ());
-    assert_eq!(*newlines, 0);
-    assert_eq!(trace.len(), 2);
-    let (newlines, trace) = get::<(), usize>(&db, TOTAL_NEWLINES, ());
-    assert_eq!(*newlines, 0);
-    assert_eq!(trace.len(), 0);
-    state.insert(1, "hello\nworld".to_string());
-    let mut inv = salsa::Invalidations::new();
-    inv.invalidate(GET_TEXT, once(i_print(&1u32)));
-    inv.invalidate(GET_FILES, once(i_print(&())));
-    let db = db.with_ground_data(state.clone(), inv);
-    let (newlines, trace) = get::<(), usize>(&db, TOTAL_NEWLINES, ());
-    assert_eq!(*newlines, 2);
-    assert_eq!(trace.len(), 4);
-    state.insert(2, "spam\neggs".to_string());
-    let mut inv = salsa::Invalidations::new();
-    inv.invalidate(GET_TEXT, once(i_print(&2u32)));
-    inv.invalidate(GET_FILES, once(i_print(&())));
-    let db = db.with_ground_data(state.clone(), inv);
-    let (newlines, trace) = get::<(), usize>(&db, TOTAL_NEWLINES, ());
-    assert_eq!(*newlines, 4);
-    assert_eq!(trace.len(), 4);
-    let mut invs = vec![];
-    for i in 0..10 {
-        let id = i + 10;
-        invs.push(i_print(&id));
-        state.insert(id, "spam".to_string());
-    }
-    let mut inv = salsa::Invalidations::new();
-    inv.invalidate(GET_TEXT, invs.into_iter());
-    inv.invalidate(GET_FILES, once(i_print(&())));
-    let db = db.with_ground_data(state.clone(), inv);
-    let (newlines, trace) = get::<(), usize>(&db, TOTAL_NEWLINES, ());
-    assert_eq!(*newlines, 14);
-    assert_eq!(trace.len(), 22);
-    state.insert(15, String::new());
-    let mut inv = salsa::Invalidations::new();
-    inv.invalidate(GET_TEXT, once(i_print(&15u32)));
-    inv.invalidate(GET_FILES, once(i_print(&())));
-    let db = db.with_ground_data(state.clone(), inv);
-    let (newlines, trace) = get::<(), usize>(&db, TOTAL_NEWLINES, ());
-    assert_eq!(*newlines, 13);
-    assert_eq!(trace.len(), 4);
-}
-fn o_print<T: Hash>(x: &T) -> salsa::OutputFingerprint {
-    let mut hasher = DefaultHasher::new();
-    x.hash(&mut hasher);
-    let hash = hasher.finish();
-    salsa::OutputFingerprint(hash)
-}
-fn i_print<T: Hash>(x: &T) -> salsa::InputFingerprint {
-    let mut hasher = DefaultHasher::new();
-    x.hash(&mut hasher);
-    let hash = hasher.finish();
-    salsa::InputFingerprint(hash)
-}
diff --git a/crates/test_utils/Cargo.toml b/crates/test_utils/Cargo.toml
index 41316581e..fe0998ab8 100644
--- a/crates/test_utils/Cargo.toml
+++ b/crates/test_utils/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "test_utils"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index 068eb80ce..ee73153f0 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -38,22 +38,44 @@ pub fn assert_eq_dbg(expected: &str, actual: &impl fmt::Debug) {
 }
 pub fn extract_offset(text: &str) -> (TextUnit, String) {
-    let cursor = "<|>";
+    match try_extract_offset(text) {
-    let cursor_pos = match text.find(cursor) {
        None => panic!("text should contain cursor marker"),
-        Some(pos) => pos,
+        Some(result) => result,
-    };
+    }
+}
+pub fn try_extract_offset(text: &str) -> Option<(TextUnit, String)> {
+    let cursor = "<|>";
+    let cursor_pos = text.find(cursor)?;
    let mut new_text = String::with_capacity(text.len() - cursor.len());
    new_text.push_str(&text[..cursor_pos]);
    new_text.push_str(&text[cursor_pos + cursor.len()..]);
    let cursor_pos = TextUnit::from(cursor_pos as u32);
-    (cursor_pos, new_text)
+    Some((cursor_pos, new_text))
 }
 pub fn extract_range(text: &str) -> (TextRange, String) {
-    let (start, text) = extract_offset(text);
+    match try_extract_range(text) {
-    let (end, text) = extract_offset(&text);
+        None => panic!("text should contain cursor marker"),
-    (TextRange::from_to(start, end), text)
+        Some(result) => result,
+    }
+}
+pub fn try_extract_range(text: &str) -> Option<(TextRange, String)> {
+    let (start, text) = try_extract_offset(text)?;
+    let (end, text) = try_extract_offset(&text)?;
+    Some((TextRange::from_to(start, end), text))
+}
+pub fn extract_ranges(text: &str) -> (Vec<TextRange>, String) {
+    let mut ranges = Vec::new();
+    let mut text = String::from(text);
+    while let Some((range, new_text)) = try_extract_range(&text) {
+        text = new_text;
+        ranges.push(range);
+    }
+    (ranges, text)
 }
 pub fn add_cursor(text: &str, offset: TextUnit) -> String {
diff --git a/crates/tools/Cargo.toml b/crates/tools/Cargo.toml
index d03910986..e2fecc60d 100644
--- a/crates/tools/Cargo.toml
+++ b/crates/tools/Cargo.toml
@@ -1,4 +1,5 @@
 [package]
+edition = "2018"
 name = "tools"
 version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
diff --git a/editors/code/src/extension.ts b/editors/code/src/extension.ts
index ff8f23c7a..d1c525f68 100644
--- a/editors/code/src/extension.ts
+++ b/editors/code/src/extension.ts
@@ -20,8 +20,8 @@ export function activate(context: vscode.ExtensionContext) {
        f: (...args: any[]) => Promise<boolean>
    ) {
        const defaultCmd = `default:${name}`;
-        const original = async (...args: any[]) =>
+        const original = (...args: any[]) =>
-            await vscode.commands.executeCommand(defaultCmd, ...args);
+            vscode.commands.executeCommand(defaultCmd, ...args);
        registerCommand(name, async (...args: any[]) => {
            const editor = vscode.window.activeTextEditor;