442 files changed, 39318 insertions, 30822 deletions

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index ed9191c49..20663196d 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -16,25 +16,25 @@ env:
   RUSTUP_MAX_RETRIES: 10
 
 jobs:
-  rust-audit:
-    name: Audit Rust vulnerabilities
-    runs-on: ubuntu-latest
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v2
+  # rust-audit:
+  #   name: Audit Rust vulnerabilities
+  #   runs-on: ubuntu-latest
+  #   steps:
+  #   - name: Checkout repository
+  #     uses: actions/checkout@v2
 
-    - uses: actions-rs/[email protected]
-      with:
-        crate: cargo-audit
-        use-tool-cache: true
+  #   - uses: actions-rs/[email protected]
+  #     with:
+  #       crate: cargo-audit
+  #       use-tool-cache: true
 
-    - run: cargo audit
+  #   - run: cargo audit
 
   rust:
     name: Rust
     runs-on: ${{ matrix.os }}
     env:
-     CC: deny_c
+      CC: deny_c
 
     strategy:
       fail-fast: false
@@ -64,26 +64,22 @@ jobs:
     - if: matrix.os == 'ubuntu-latest'
       run: sudo chown -R $(whoami):$(id -ng) ~/.cargo/
 
-    - name: Cache cargo registry
-      uses: actions/cache@v1
-      with:
-        path: ~/.cargo/registry
-        key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
-
-    - name: Cache cargo index
-      uses: actions/cache@v1
+    - name: Cache cargo directories
+      uses: actions/cache@v2
       with:
-        path: ~/.cargo/git
-        key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
 
     - name: Cache cargo target dir
-      uses: actions/cache@v1
+      uses: actions/cache@v2
       with:
         path: target
         key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
 
     - name: Compile
-      run: cargo test --no-run
+      run: cargo test --no-run --locked
 
     - name: Test
       run: cargo test
@@ -95,6 +91,36 @@ jobs:
       if: matrix.os == 'windows-latest'
       run: Remove-Item ./target/debug/xtask.exe, ./target/debug/deps/xtask.exe
 
+  # Weird target to catch non-portable code
+  rust-power:
+    name: Rust Power
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: Install Rust toolchain
+      uses: actions-rs/toolchain@v1
+      with:
+        toolchain: stable
+        profile: minimal
+        override: true
+        target: 'powerpc-unknown-linux-gnu'
+
+    - run: sudo chown -R $(whoami):$(id -ng) ~/.cargo/
+
+    - name: Cache cargo directories
+      uses: actions/cache@v2
+      with:
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Check
+      run: cargo check --target=powerpc-unknown-linux-gnu --all-targets
+
   typescript:
     name: TypeScript
     strategy:
@@ -103,7 +129,7 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
 
     runs-on: ${{ matrix.os }}
-    
+
     steps:
     - name: Checkout repository
       uses: actions/checkout@v2
@@ -116,9 +142,9 @@ jobs:
     - run: npm ci
       working-directory: ./editors/code
 
-    - run: npm audit || { sleep 10 && npm audit; } || { sleep 30 && npm audit; }
-      if: runner.os == 'Linux'
-      working-directory: ./editors/code
+#    - run: npm audit || { sleep 10 && npm audit; } || { sleep 30 && npm audit; }
+#      if: runner.os == 'Linux'
+#      working-directory: ./editors/code
 
     - run: npm run lint
       working-directory: ./editors/code
diff --git a/.gitignore b/.gitignore
index dab51647d..472fe1a13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,4 +7,5 @@ crates/*/target
 *.log
 *.iml
 .vscode/settings.json
-*.html
+generated_assists.adoc
+generated_features.adoc
diff --git a/Cargo.lock b/Cargo.lock
index 9981a2e33..cde82397c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,23 +2,47 @@
 # It is not intended for manual editing.
 [[package]]
 name = "addr2line"
-version = "0.12.1"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a49806b9dadc843c61e7c97e72490ad7f7220ae249012fbda9ad0609457c0543"
+checksum = "1b6a2d3371669ab3ca9797670853d61402b03d0b4b9ebf33d677dfa720203072"
 dependencies = [
  "gimli",
 ]
 
 [[package]]
+name = "adler"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee2a4ec343196209d6594e19543ae87a39f96d5534d7174822a3ad825dd6ed7e"
+
+[[package]]
 name = "aho-corasick"
-version = "0.7.10"
+version = "0.7.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8716408b8bc624ed7f65d223ddb9ac2d044c0547b6fa4b0d554f3a9540496ada"
+checksum = "043164d8ba5c4c3035fec9bbee8647c0261d788f3474306f93bb65901cae0e86"
 dependencies = [
  "memchr",
 ]
 
 [[package]]
+name = "ansi_term"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+dependencies = [
+ "winapi 0.3.9",
+]
+
+[[package]]
+name = "ansi_term"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
+dependencies = [
+ "winapi 0.3.9",
+]
+
+[[package]]
 name = "anyhow"
 version = "1.0.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -44,7 +68,7 @@ checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 dependencies = [
  "hermit-abi",
  "libc",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
@@ -55,22 +79,23 @@ checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
 
 [[package]]
 name = "backtrace"
-version = "0.3.48"
+version = "0.3.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0df2f85c8a2abbe3b7d7e748052fdd9b76a0458fdeb16ad4223f5eca78c7c130"
+checksum = "46254cf2fdcdf1badb5934448c1bcbe046a56537b3987d96c51a7afc5d03f293"
 dependencies = [
  "addr2line",
  "cfg-if",
  "libc",
+ "miniz_oxide",
  "object",
  "rustc-demangle",
 ]
 
 [[package]]
 name = "base64"
-version = "0.12.1"
+version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53d1ccbaf7d9ec9537465a97bf19edc1a4e158ecb49fc16178202238c569cc42"
+checksum = "3441f0f7b02788e948e47f457ca01f1d7e6d92c693bc132c22b087d3141c03ff"
 
 [[package]]
 name = "bitflags"
@@ -88,6 +113,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "byteorder"
+version = "1.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
+
+[[package]]
 name = "cargo_metadata"
 version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -101,9 +132,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.0.54"
+version = "1.0.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7bbb73db36c1246e9034e307d0fba23f9a2e251faa47ade70c1bd252220c8311"
+checksum = "f9a06fb2e53271d7c279ec1efea6ab691c35a2ae67ec0d91d7acec0caf13b518"
 
 [[package]]
 name = "cfg-if"
@@ -113,8 +144,9 @@ checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
 [[package]]
 name = "chalk-derive"
-version = "0.10.1-dev"
-source = "git+https://github.com/rust-lang/chalk.git?rev=329b7f3fdd2431ed6f6778cde53f22374c7d094c#329b7f3fdd2431ed6f6778cde53f22374c7d094c"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9396f12a23b1a40d5019aa81bc0cbd7ccd2c9736d6bc4afc95868533c2346dcb"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -123,86 +155,95 @@ dependencies = [
 ]
 
 [[package]]
-name = "chalk-engine"
-version = "0.10.1-dev"
-source = "git+https://github.com/rust-lang/chalk.git?rev=329b7f3fdd2431ed6f6778cde53f22374c7d094c#329b7f3fdd2431ed6f6778cde53f22374c7d094c"
+name = "chalk-ir"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87e9c67d500717d65ede27affb7ae40efe240d86fbefff1006fe0ffb62d4caf9"
 dependencies = [
  "chalk-derive",
- "chalk-ir",
- "rustc-hash",
+ "lazy_static",
 ]
 
 [[package]]
-name = "chalk-ir"
-version = "0.10.1-dev"
-source = "git+https://github.com/rust-lang/chalk.git?rev=329b7f3fdd2431ed6f6778cde53f22374c7d094c#329b7f3fdd2431ed6f6778cde53f22374c7d094c"
+name = "chalk-recursive"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a8fd2ac0fc06c857b95614d229bbe8ea317d1d94a7e8b9442a3f05c9a2c2d5f4"
 dependencies = [
  "chalk-derive",
- "lazy_static",
+ "chalk-ir",
+ "chalk-solve",
+ "rustc-hash",
+ "tracing",
 ]
 
 [[package]]
 name = "chalk-solve"
-version = "0.10.1-dev"
-source = "git+https://github.com/rust-lang/chalk.git?rev=329b7f3fdd2431ed6f6778cde53f22374c7d094c#329b7f3fdd2431ed6f6778cde53f22374c7d094c"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a79166f2405c1e51eadcc1344f5ee833c7b391532dd78f64a0731a9a123cc58"
 dependencies = [
  "chalk-derive",
- "chalk-engine",
  "chalk-ir",
  "ena",
  "itertools",
  "petgraph",
  "rustc-hash",
+ "tracing",
+ "tracing-subscriber",
+ "tracing-tree",
 ]
 
 [[package]]
-name = "clicolors-control"
-version = "1.0.1"
+name = "chrono"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90082ee5dcdd64dc4e9e0d37fbf3ee325419e39c0092191e0393df65518f741e"
+checksum = "c74d84029116787153e02106bf53e66828452a4b325cc8652b788b5967c0a0b6"
 dependencies = [
- "atty",
- "lazy_static",
- "libc",
- "winapi 0.3.8",
+ "num-integer",
+ "num-traits",
+ "time",
 ]
 
 [[package]]
 name = "cloudabi"
-version = "0.0.3"
+version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
+checksum = "4344512281c643ae7638bbabc3af17a11307803ec8f0fcad9fae512a8bf36467"
 dependencies = [
  "bitflags",
 ]
 
 [[package]]
+name = "cmake"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e56268c17a6248366d66d4a47a3381369d068cce8409bb1716ed77ea32163bb"
+dependencies = [
+ "cc",
+]
+
+[[package]]
 name = "console"
-version = "0.10.3"
+version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2586208b33573b7f76ccfbe5adb076394c88deaf81b84d7213969805b0a952a7"
+checksum = "8c0994e656bba7b922d8dd1245db90672ffb701e684e45be58f20719d69abc5a"
 dependencies = [
- "clicolors-control",
  "encode_unicode",
  "lazy_static",
  "libc",
  "terminal_size",
  "termios",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
-name = "crossbeam"
-version = "0.7.3"
+name = "crc32fast"
+version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "69323bff1fb41c635347b8ead484a5ca6c3f11914d784170b158d8449ab07f8e"
+checksum = "ba125de2af0df55319f41944744ad91c71113bf74a4646efff39afe1f6842db1"
 dependencies = [
  "cfg-if",
- "crossbeam-channel",
- "crossbeam-deque",
- "crossbeam-epoch",
- "crossbeam-queue",
- "crossbeam-utils",
 ]
 
 [[package]]
@@ -243,12 +284,13 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-queue"
-version = "0.2.2"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab6bffe714b6bb07e42f201352c34f51fefd355ace793f9e638ebd52d23f98d2"
+checksum = "774ba60a54c213d409d5353bda12d49cd68d14e45036a285234c8d6f91f92570"
 dependencies = [
  "cfg-if",
  "crossbeam-utils",
+ "maybe-uninit",
 ]
 
 [[package]]
@@ -276,9 +318,9 @@ checksum = "69b26e475fd29098530e709294e94e661974c851aed42512793f120fed4e199f"
 
 [[package]]
 name = "dtoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4358a9e11b9a09cf52383b451b49a169e8d797b68aa02301ff586d70d9661ea3"
+checksum = "134951f4028bdadb9b84baf4232681efbf277da25144b9b0ad65df75946c422b"
 
 [[package]]
 name = "either"
@@ -311,6 +353,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "expect"
+version = "0.1.0"
+dependencies = [
+ "difference",
+ "once_cell",
+ "stdx",
+]
+
+[[package]]
 name = "filetime"
 version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -319,7 +370,7 @@ dependencies = [
  "cfg-if",
  "libc",
  "redox_syscall",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
@@ -329,6 +380,30 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37ab347416e802de484e4d03c7316c48f1ecb56574dfd4a46a80f173ce1de04d"
 
 [[package]]
+name = "flate2"
+version = "1.0.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68c90b0fc46cf89d227cc78b40e494ff81287a92dd07631e5af0d06fe3cf885e"
+dependencies = [
+ "cfg-if",
+ "crc32fast",
+ "libc",
+ "miniz_oxide",
+]
+
+[[package]]
+name = "flycheck"
+version = "0.1.0"
+dependencies = [
+ "cargo_metadata",
+ "crossbeam-channel",
+ "jod-thread",
+ "log",
+ "ra_toolchain",
+ "serde_json",
+]
+
+[[package]]
 name = "fnv"
 version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -342,9 +417,9 @@ checksum = "5f2a4a2034423744d2cc7ca2068453168dcdb82c438419e639a26bd87839c674"
 
 [[package]]
 name = "fsevent"
-version = "0.4.0"
+version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ab7d1bd1bd33cc98b0889831b72da23c0aa4df9cec7e0702f46ecea04b35db6"
+checksum = "97f347202c95c98805c216f9e1df210e8ebaec9fdb2365700a43c10797a35e63"
 dependencies = [
  "bitflags",
  "fsevent-sys",
@@ -352,9 +427,9 @@ dependencies = [
 
 [[package]]
 name = "fsevent-sys"
-version = "2.0.1"
+version = "3.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f41b048a94555da0f42f1d632e2e19510084fb8e303b0daa2816e733fb3644a0"
+checksum = "77a29c77f1ca394c3e73a9a5d24cfcabb734682d9634fc398f2204a63c994120"
 dependencies = [
  "libc",
 ]
@@ -394,9 +469,9 @@ dependencies = [
 
 [[package]]
 name = "gimli"
-version = "0.21.0"
+version = "0.22.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bcc8e0c9bce37868955864dbecd2b1ab2bdf967e6f28066d65aaac620444b65c"
+checksum = "aaf91faf136cb47367fa430cd46e37a788775e7fa104f8b4bcb3861dc389b724"
 
 [[package]]
 name = "globset"
@@ -433,9 +508,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.13"
+version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91780f809e750b0a89f5544be56617ff6b1227ee485bcb06ebe10cdf89bd3b71"
+checksum = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
 dependencies = [
  "libc",
 ]
@@ -446,7 +521,7 @@ version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2456aef2e6b6a9784192ae780c0f15bc57df0e918585282325e8c8ac27737654"
 dependencies = [
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
@@ -462,18 +537,18 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.3.2"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "076f042c5b7b98f31d205f1249267e12a6518c1481e9dae9764af19b707d2292"
+checksum = "c398b2b113b55809ceb9ee3e753fcbac793f1956663f3c36549c1346015c2afe"
 dependencies = [
  "autocfg",
 ]
 
 [[package]]
 name = "inotify"
-version = "0.7.0"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "24e40d6fd5d64e2082e0c796495c8ef5ad667a96d03e5aaa0becfd9d47bcbfb8"
+checksum = "46dd0a94b393c730779ccfd2a872b67b1eb67be3fc33082e733bdb38b5fde4d4"
 dependencies = [
  "bitflags",
  "inotify-sys",
@@ -491,9 +566,9 @@ dependencies = [
 
 [[package]]
 name = "insta"
-version = "0.16.0"
+version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8386e795fb3927131ea4cede203c529a333652eb6dc4ff29616b832b27e9b096"
+checksum = "617e921abc813f96a3b00958c079e7bf1e2db998f8a04f1546dd967373a418ee"
 dependencies = [
  "console",
  "difference",
@@ -504,6 +579,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "instant"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b141fdc7836c525d4d594027d318c84161ca17aaf8113ab1f81ab93ae897485"
+
+[[package]]
 name = "iovec"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -523,9 +604,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
+checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
 [[package]]
 name = "jemalloc-ctl"
@@ -561,9 +642,9 @@ dependencies = [
 
 [[package]]
 name = "jod-thread"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4022656272c3e564a7cdebcaaba6518d844b0d0c1836597196efb5bfeb98bb49"
+checksum = "8b23360e99b8717f20aaa4598f5a6541efbe30630039fbc7706cf954a87947ae"
 
 [[package]]
 name = "kernel32-sys"
@@ -589,9 +670,9 @@ checksum = "b294d6fa9ee409a054354afc4352b0b9ef7ca222c69b8812cbea9e7d2bf3783f"
 
 [[package]]
 name = "libc"
-version = "0.2.71"
+version = "0.2.72"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9457b06509d27052635f90d6466700c65095fdf75409b3fbdd903e988b886f49"
+checksum = "a9f8082297d534141b30c8d39e9b1773713ab50fdbe4ff30f750d063b3bfd701"
 
 [[package]]
 name = "libloading"
@@ -599,7 +680,16 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2cadb8e769f070c45df05c78c7520eb4cd17061d4ab262e43cfc68b4d00ac71c"
 dependencies = [
- "winapi 0.3.8",
+ "winapi 0.3.9",
+]
+
+[[package]]
+name = "libmimalloc-sys"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a27252ec1d0c4e0dd6142cbc572da50b363ab56fc334f7aa8fadf295b2e24e74"
+dependencies = [
+ "cmake",
 ]
 
 [[package]]
@@ -610,9 +700,9 @@ checksum = "8dd5a6d5999d9907cda8ed67bbd137d3af8085216c2ac62de5be860bd41f304a"
 
 [[package]]
 name = "lock_api"
-version = "0.3.4"
+version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4da24a77a3d8a6d4862d95f72e6fdb9c09a643ecdb402d754004a557f2bec75"
+checksum = "28247cc5a5be2f05fbcd76dd0cf2c7d3b5400cb978a28042abcd4fa0b3f8261c"
 dependencies = [
  "scopeguard",
 ]
@@ -628,9 +718,9 @@ dependencies = [
 
 [[package]]
 name = "lsp-server"
-version = "0.3.2"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dccec31bfd027ac0dd288a78e19005fd89624d9099456e284b5241316a6c3072"
+checksum = "53b4ace8ebe5d2aff3687ce0ed507f6020d6a47a7de2b0d3d664ea237ffb0c62"
 dependencies = [
  "crossbeam-channel",
  "log",
@@ -640,9 +730,9 @@ dependencies = [
 
 [[package]]
 name = "lsp-types"
-version = "0.74.2"
+version = "0.77.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b360754e89e0e13c114245131382ba921d4ff1efabb918e549422938aaa8d392"
+checksum = "897c6c8930fbf12b67deffc83729287bb379dd5e5a4bd0ae2d81eff8d6503db6"
 dependencies = [
  "base64",
  "bitflags",
@@ -653,6 +743,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "matchers"
+version = "0.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f099785f7595cc4b4553a174ce30dd7589ef93391ff414dbb67f62392b9e0ce1"
+dependencies = [
+ "regex-automata",
+]
+
+[[package]]
 name = "matches"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -677,19 +776,37 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6585fd95e7bb50d6cc31e20d4cf9afb4e2ba16c5846fc76793f11218da9c475b"
 dependencies = [
  "libc",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
 name = "memoffset"
-version = "0.5.4"
+version = "0.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4fc2c02a7e374099d4ee95a193111f72d2110197fe200272371758f6c3643d8"
+checksum = "c198b026e1bbf08a937e94c6c60f9ec4a2267f5b0d2eec9c1b21b061ce2be55f"
 dependencies = [
  "autocfg",
 ]
 
 [[package]]
+name = "mimalloc"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c52de2069999f01bd26436564dbe7de3a87898feeb7a0d0ff9eb20a05bb7ca0"
+dependencies = [
+ "libmimalloc-sys",
+]
+
+[[package]]
+name = "miniz_oxide"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be0f75932c1f6cfae3c04000e40114adf955636e19040f9c0a2c380702aa1c7f"
+dependencies = [
+ "adler",
+]
+
+[[package]]
 name = "mio"
 version = "0.6.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -740,16 +857,18 @@ checksum = "2ba7c918ac76704fb42afcbbb43891e72731f3dcca3bef2a19786297baf14af7"
 dependencies = [
  "cfg-if",
  "libc",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
 name = "notify"
-version = "4.0.15"
+version = "5.0.0-pre.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80ae4a7688d1fab81c5bf19c64fc8db920be8d519ce6336ed4e7efe024724dbd"
+checksum = "77d03607cf88b4b160ba0e9ed425fff3cee3b55ac813f0c685b3a3772da37d0e"
 dependencies = [
+ "anymap",
  "bitflags",
+ "crossbeam-channel",
  "filetime",
  "fsevent",
  "fsevent-sys",
@@ -758,7 +877,26 @@ dependencies = [
  "mio",
  "mio-extras",
  "walkdir",
- "winapi 0.3.8",
+ "winapi 0.3.9",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d59457e662d541ba17869cf51cf177c0b5f0cbf476c66bdc90bf1edac4f875b"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac267bcc07f48ee5f8935ab0d24f316fb722d7a1292e2913f0cc196b29ffd611"
+dependencies = [
+ "autocfg",
 ]
 
 [[package]]
@@ -773,9 +911,9 @@ dependencies = [
 
 [[package]]
 name = "object"
-version = "0.19.0"
+version = "0.20.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9cbca9424c482ee628fa549d9c812e2cd22f1180b9222c9200fdfa6eb31aecb2"
+checksum = "1ab52be62400ca80aa00285d25253d7f7c437b7375c4de678f5405d3afe82ca5"
 
 [[package]]
 name = "once_cell"
@@ -785,33 +923,35 @@ checksum = "0b631f7e854af39a1739f401cf34a8a013dfe09eac4fa4dba91e9768bd28168d"
 
 [[package]]
 name = "parking_lot"
-version = "0.10.2"
+version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d3a704eb390aafdc107b0e392f56a82b668e3a71366993b5340f5833fd62505e"
+checksum = "a4893845fa2ca272e647da5d0e46660a314ead9c2fdd9a883aabc32e481a8733"
 dependencies = [
+ "instant",
  "lock_api",
  "parking_lot_core",
 ]
 
 [[package]]
 name = "parking_lot_core"
-version = "0.7.2"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d58c7c768d4ba344e3e8d72518ac13e259d7c7ade24167003b8488e10b6740a3"
+checksum = "c361aa727dd08437f2f1447be8b59a33b0edd15e0fcee698f935613d9efbca9b"
 dependencies = [
  "cfg-if",
  "cloudabi",
+ "instant",
  "libc",
  "redox_syscall",
  "smallvec",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
 name = "paste"
-version = "0.1.15"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d53181dcd37421c08d3b69f887784956674d09c3f9a47a04fece2b130a5b346b"
+checksum = "45ca20c77d80be666aef2b45486da86238fabe33e38306bd3118fe4af33fa880"
 dependencies = [
  "paste-impl",
  "proc-macro-hack",
@@ -819,17 +959,18 @@ dependencies = [
 
 [[package]]
 name = "paste-impl"
-version = "0.1.15"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05ca490fa1c034a71412b4d1edcb904ec5a0981a4426c9eb2128c0fda7a68d17"
+checksum = "d95a7db200b97ef370c8e6de0088252f7e0dfff7d047a28528e47456c0fc98b6"
 dependencies = [
  "proc-macro-hack",
- "proc-macro2",
- "quote",
- "syn",
 ]
 
 [[package]]
+name = "paths"
+version = "0.1.0"
+
+[[package]]
 name = "percent-encoding"
 version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -847,9 +988,9 @@ dependencies = [
 
 [[package]]
 name = "pico-args"
-version = "0.3.1"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ad1f1b834a05d42dae330066e9699a173b28185b3bdc3dbf14ca239585de8cc"
+checksum = "1b1eee8b1f4966c8343d7ca0f5a8452cd35d5610a2e0efbe2a68cae44bef2046"
 
 [[package]]
 name = "plain"
@@ -871,18 +1012,18 @@ checksum = "7e0456befd48169b9f13ef0f0ad46d492cf9d2dbb918bcf38e01eed4ce3ec5e4"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.17"
+version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1502d12e458c49a4c9cbff560d0fe0060c252bc29799ed94ca2ed4bb665a0101"
+checksum = "beae6331a816b1f65d04c45b078fd8e6c93e8071771f41b8163255bbd8d7c8fa"
 dependencies = [
  "unicode-xid",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.6"
+version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54a21852a652ad6f610c9510194f398ff6f8692e334fd1145fed931f7fbe44ea"
+checksum = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
 dependencies = [
  "proc-macro2",
 ]
@@ -927,22 +1068,11 @@ dependencies = [
  "ra_prof",
  "ra_syntax",
  "ra_tt",
- "relative-path",
  "rustc-hash",
  "salsa",
+ "stdx",
  "test_utils",
-]
-
-[[package]]
-name = "ra_flycheck"
-version = "0.1.0"
-dependencies = [
- "cargo_metadata",
- "crossbeam-channel",
- "jod-thread",
- "log",
- "ra_toolchain",
- "serde_json",
+ "vfs",
 ]
 
 [[package]]
@@ -968,6 +1098,7 @@ dependencies = [
  "ra_prof",
  "ra_syntax",
  "rustc-hash",
+ "stdx",
 ]
 
 [[package]]
@@ -977,7 +1108,11 @@ dependencies = [
  "anymap",
  "drop_bomb",
  "either",
+ "expect",
+ "fst",
+ "indexmap",
  "insta",
+ "itertools",
  "log",
  "once_cell",
  "ra_arena",
@@ -989,6 +1124,7 @@ dependencies = [
  "ra_syntax",
  "ra_tt",
  "rustc-hash",
+ "smallvec",
  "stdx",
  "test_utils",
 ]
@@ -1006,6 +1142,7 @@ dependencies = [
  "ra_prof",
  "ra_syntax",
  "ra_tt",
+ "rustc-hash",
  "test_utils",
 ]
 
@@ -1015,8 +1152,10 @@ version = "0.1.0"
 dependencies = [
  "arrayvec",
  "chalk-ir",
+ "chalk-recursive",
  "chalk-solve",
  "ena",
+ "expect",
  "insta",
  "itertools",
  "log",
@@ -1031,6 +1170,9 @@ dependencies = [
  "smallvec",
  "stdx",
  "test_utils",
+ "tracing",
+ "tracing-subscriber",
+ "tracing-tree",
 ]
 
 [[package]]
@@ -1038,8 +1180,8 @@ name = "ra_ide"
 version = "0.1.0"
 dependencies = [
  "either",
+ "expect",
  "indexmap",
- "insta",
  "itertools",
  "log",
  "ra_assists",
@@ -1049,6 +1191,7 @@ dependencies = [
  "ra_hir",
  "ra_ide_db",
  "ra_prof",
+ "ra_ssr",
  "ra_syntax",
  "ra_text_edit",
  "rand",
@@ -1119,6 +1262,7 @@ dependencies = [
  "memmap",
  "ra_mbe",
  "ra_proc_macro",
+ "ra_toolchain",
  "ra_tt",
  "serde_derive",
  "test_utils",
@@ -1131,6 +1275,7 @@ dependencies = [
  "backtrace",
  "jemalloc-ctl",
  "jemallocator",
+ "mimalloc",
  "once_cell",
  "ra_arena",
 ]
@@ -1142,6 +1287,7 @@ dependencies = [
  "anyhow",
  "cargo_metadata",
  "log",
+ "paths",
  "ra_arena",
  "ra_cfg",
  "ra_db",
@@ -1150,6 +1296,20 @@ dependencies = [
  "rustc-hash",
  "serde",
  "serde_json",
+ "stdx",
+]
+
+[[package]]
+name = "ra_ssr"
+version = "0.1.0"
+dependencies = [
+ "ra_db",
+ "ra_hir",
+ "ra_ide_db",
+ "ra_syntax",
+ "ra_text_edit",
+ "rustc-hash",
+ "test_utils",
 ]
 
 [[package]]
@@ -1157,10 +1317,12 @@ name = "ra_syntax"
 version = "0.1.0"
 dependencies = [
  "arrayvec",
+ "expect",
  "itertools",
  "once_cell",
  "ra_parser",
  "ra_text_edit",
+ "rayon",
  "rowan",
  "rustc-ap-rustc_lexer",
  "rustc-hash",
@@ -1190,22 +1352,7 @@ name = "ra_tt"
 version = "0.1.0"
 dependencies = [
  "smol_str",
-]
-
-[[package]]
-name = "ra_vfs"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cbf31a173fc77ec59c27cf39af6baa137b40f4dbd45a8b3eccb1b2e4cfc922c1"
-dependencies = [
- "crossbeam-channel",
- "jod-thread",
- "log",
- "notify",
- "parking_lot",
- "relative-path",
- "rustc-hash",
- "walkdir",
+ "stdx",
 ]
 
 [[package]]
@@ -1261,10 +1408,11 @@ dependencies = [
 
 [[package]]
 name = "rayon"
-version = "1.3.0"
+version = "1.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db6ce3297f9c85e16621bb8cca38a06779ffc31bb8184e1be4bed2be4678a098"
+checksum = "62f02856753d04e03e26929f820d0a0a337ebe71f849801eea335d464b349080"
 dependencies = [
+ "autocfg",
  "crossbeam-deque",
  "either",
  "rayon-core",
@@ -1272,9 +1420,9 @@ dependencies = [
 
 [[package]]
 name = "rayon-core"
-version = "1.7.0"
+version = "1.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08a89b46efaf957e52b18062fb2f4660f8b8a4dde1807ca002690868ef2c85a9"
+checksum = "e92e15d89083484e11353891f1af602cc661426deb9564c298b270c726973280"
 dependencies = [
  "crossbeam-deque",
  "crossbeam-queue",
@@ -1285,9 +1433,9 @@ dependencies = [
 
 [[package]]
 name = "redox_syscall"
-version = "0.1.56"
+version = "0.1.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2439c63f3f6139d1b57529d16bc3b8bb855230c8efcc5d3a896c8bea7c3b1e84"
+checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
 
 [[package]]
 name = "regex"
@@ -1302,24 +1450,28 @@ dependencies = [
 ]
 
 [[package]]
-name = "regex-syntax"
-version = "0.6.18"
+name = "regex-automata"
+version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "26412eb97c6b088a6997e05f69403a802a92d520de2f8e63c2b65f9e0f47c4e8"
+checksum = "ae1ded71d66a4a97f5e961fd0cb25a5f366a42a41570d16a763a69c092c26ae4"
+dependencies = [
+ "byteorder",
+ "regex-syntax",
+]
 
 [[package]]
-name = "relative-path"
-version = "1.0.0"
+name = "regex-syntax"
+version = "0.6.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bedde000f40f2921ce439ea165c9c53fd629bfa115140c72e22aceacb4a21954"
+checksum = "26412eb97c6b088a6997e05f69403a802a92d520de2f8e63c2b65f9e0f47c4e8"
 
 [[package]]
 name = "remove_dir_all"
-version = "0.5.2"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a83fa3702a688b9359eccba92d153ac33fd2e8462f9e0e3fdf155239ea7792e"
+checksum = "3acd125665422973a33ac9d3dd2df85edad0f4ae9b00dafb1a05e43a9f5ef8e7"
 dependencies = [
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
@@ -1341,8 +1493,9 @@ dependencies = [
  "anyhow",
  "crossbeam-channel",
  "env_logger",
+ "expect",
+ "flycheck",
  "globset",
- "insta",
  "itertools",
  "jod-thread",
  "log",
@@ -1352,21 +1505,22 @@ dependencies = [
  "pico-args",
  "ra_cfg",
  "ra_db",
- "ra_flycheck",
  "ra_hir",
  "ra_hir_def",
  "ra_hir_ty",
  "ra_ide",
+ "ra_ide_db",
  "ra_mbe",
  "ra_proc_macro_srv",
  "ra_prof",
  "ra_project_model",
+ "ra_ssr",
  "ra_syntax",
  "ra_text_edit",
+ "ra_toolchain",
  "ra_tt",
- "ra_vfs",
  "rand",
- "relative-path",
+ "rayon",
  "rustc-hash",
  "serde",
  "serde_json",
@@ -1374,14 +1528,16 @@ dependencies = [
  "tempfile",
  "test_utils",
  "threadpool",
- "winapi 0.3.8",
+ "vfs",
+ "vfs-notify",
+ "winapi 0.3.9",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_lexer"
-version = "661.0.0"
+version = "666.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a6d88abd7c634b52557e46fc7ba47644f0cbe45c358c33f51c532d60d1da239e"
+checksum = "4e00c526f9f8430ea4cd2178d25b02bfc7debe6677350c57292f92f50e65d2fe"
 dependencies = [
  "unicode-xid",
 ]
@@ -1400,18 +1556,19 @@ checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
 [[package]]
 name = "ryu"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed3d612bc64430efeb3f7ee6ef26d590dce0c43249217bddc62112540c7941e1"
+checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
 
 [[package]]
 name = "salsa"
-version = "0.14.1"
+version = "0.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a006c56096acaaa5e82e5974c28d05ff1e84aa70615f19c53fecf8a1afb2fd2"
+checksum = "885b4b99dde959decc84e85dd943bd140b4aabd62db2f8206ef5270f77ec20b9"
 dependencies = [
- "crossbeam",
+ "crossbeam-utils",
  "indexmap",
+ "lock_api",
  "log",
  "parking_lot",
  "rand",
@@ -1422,9 +1579,9 @@ dependencies = [
 
 [[package]]
 name = "salsa-macros"
-version = "0.14.1"
+version = "0.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "038a09b6271446f1123f142fe7e5bef6d4687c4cf82e6986be574c2af3745530"
+checksum = "2c280ac85b15ac214b86ac4b407626a48e6a1c4f90769a582fec74aa57942b9f"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -1491,18 +1648,18 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
-version = "1.0.111"
+version = "1.0.114"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9124df5b40cbd380080b2cc6ab894c040a3070d995f5c9dc77e18c34a8ae37d"
+checksum = "5317f7588f0a5078ee60ef675ef96735a1442132dc645eb1d12c018620ed8cd3"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.111"
+version = "1.0.114"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f2c3ac8e6ca1e9c80b8be1023940162bf81ae3cffbb1809474152f2ce1eb250"
+checksum = "2a0be94b04690fbaed37cddffc5c134bf537c8e3329d53e982fe04c374978f8e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1511,9 +1668,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.53"
+version = "1.0.56"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "993948e75b189211a9b31a7528f950c6adc21f9720b6438ff80a7fa2f864cea2"
+checksum = "3433e879a558dde8b5e8feb2a04899cf34fdde1fafb894687e52105fc1162ac3"
 dependencies = [
  "itoa",
  "ryu",
@@ -1522,9 +1679,9 @@ dependencies = [
 
 [[package]]
 name = "serde_repr"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd02c7587ec314570041b2754829f84d873ced14a96d1fd1823531e11db40573"
+checksum = "2dc6b7951b17b051f3210b063f12cc17320e2fe30ae05b0fe2a3abb068551c76"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1533,9 +1690,9 @@ dependencies = [
 
 [[package]]
 name = "serde_yaml"
-version = "0.8.12"
+version = "0.8.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "16c7a592a1ec97c9c1c68d75b6e537dcbf60c7618e038e7841e00af1d9ccf0c4"
+checksum = "ae3e2dd40a7cdc18ca80db804b7f461a39bb721160a85c9a1fa30134bf3c02a5"
 dependencies = [
  "dtoa",
  "linked-hash-map",
@@ -1544,6 +1701,15 @@ dependencies = [
 ]
 
 [[package]]
+name = "sharded-slab"
+version = "0.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06d5a3f5166fb5b42a5439f2eee8b9de149e235961e3eb21c5808fc3ea17ff3e"
+dependencies = [
+ "lazy_static",
+]
+
+[[package]]
 name = "slab"
 version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1551,15 +1717,15 @@ checksum = "c111b5bd5695e56cffe5129854aa230b39c93a305372fdbb2668ca2394eea9f8"
 
 [[package]]
 name = "smallvec"
-version = "1.4.0"
+version = "1.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7cb5678e1615754284ec264d9bb5b4c27d2018577fd90ac0ceb578591ed5ee4"
+checksum = "3757cb9d89161a2f24e1cf78efa0c1fcff485d18e3f55e0aa3480824ddaa0f3f"
 
 [[package]]
 name = "smol_str"
-version = "0.1.15"
+version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "34836c9a295c62c2ce3514471117c5cb269891e8421b2aafdd910050576c4d8b"
+checksum = "2f7909a1d8bc166a862124d84fdc11bda0ea4ed3157ccca662296919c2972db1"
 dependencies = [
  "serde",
 ]
@@ -1576,9 +1742,9 @@ checksum = "ab16ced94dbd8a46c82fd81e3ed9a8727dac2977ea869d217bcc4ea1f122e81f"
 
 [[package]]
 name = "syn"
-version = "1.0.29"
+version = "1.0.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb37da98a55b1d08529362d9cbb863be17556873df2585904ab9d2bc951291d0"
+checksum = "936cae2873c940d92e697597c5eee105fb570cd5689c695806f672883653349b"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1587,9 +1753,9 @@ dependencies = [
 
 [[package]]
 name = "synstructure"
-version = "0.12.3"
+version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "67656ea1dc1b41b1451851562ea232ec2e5a80242139f7e679ceccfb5d61f545"
+checksum = "b834f2d66f734cb897113e34aaff2f1ab4719ca946f9a7358dba8f8064148701"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1608,17 +1774,26 @@ dependencies = [
  "rand",
  "redox_syscall",
  "remove_dir_all",
- "winapi 0.3.8",
+ "winapi 0.3.9",
+]
+
+[[package]]
+name = "termcolor"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb6bfa289a4d7c5766392812c0a1f4c1ba45afa1ad47803c11e1f407d846d75f"
+dependencies = [
+ "winapi-util",
 ]
 
 [[package]]
 name = "terminal_size"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8038f95fc7a6f351163f4b964af631bd26c9e828f7db085f2a84aca56f70d13b"
+checksum = "9a14cd9f8c72704232f0bfc8455c0e861f0ad4eb60cc9ec8a170e231414c1e13"
 dependencies = [
  "libc",
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
@@ -1635,10 +1810,9 @@ name = "test_utils"
 version = "0.1.0"
 dependencies = [
  "difference",
- "ra_cfg",
- "relative-path",
  "rustc-hash",
  "serde_json",
+ "stdx",
  "text-size",
 ]
 
@@ -1673,6 +1847,108 @@ dependencies = [
 ]
 
 [[package]]
+name = "time"
+version = "0.1.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca8a50ef2360fbd1eeb0ecd46795a87a19024eb4b53c5dc916ca1fd95fe62438"
+dependencies = [
+ "libc",
+ "winapi 0.3.9",
+]
+
+[[package]]
+name = "tinyvec"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53953d2d3a5ad81d9f844a32f14ebb121f50b650cd59d0ee2a07cf13c617efed"
+
+[[package]]
+name = "tracing"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2e2a2de6b0d5cbb13fc21193a2296888eaab62b6044479aafb3c54c01c29fcd"
+dependencies = [
+ "cfg-if",
+ "tracing-attributes",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-attributes"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0693bf8d6f2bf22c690fc61a9d21ac69efdbb894a17ed596b9af0f01e64b84b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-core"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94ae75f0d28ae10786f3b1895c55fe72e79928fd5ccdebb5438c75e93fec178f"
+dependencies = [
+ "lazy_static",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e0f8c7178e13481ff6765bd169b33e8d554c5d2bbede5e32c356194be02b9b9"
+dependencies = [
+ "lazy_static",
+ "log",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-serde"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6ccba2f8f16e0ed268fc765d9b7ff22e965e7185d32f8f1ec8294fe17d86e79"
+dependencies = [
+ "serde",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c72c8cf3ec4ed69fef614d011a5ae4274537a8a8c59133558029bd731eb71659"
+dependencies = [
+ "ansi_term 0.11.0",
+ "chrono",
+ "lazy_static",
+ "matchers",
+ "regex",
+ "serde",
+ "serde_json",
+ "sharded-slab",
+ "smallvec",
+ "tracing-core",
+ "tracing-log",
+ "tracing-serde",
+]
+
+[[package]]
+name = "tracing-tree"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37ee7f0f53ed2093971a698db799ef56a2dfd89b32e3aeb5165f0e637a02be04"
+dependencies = [
+ "ansi_term 0.12.1",
+ "atty",
+ "chrono",
+ "termcolor",
+ "tracing",
+ "tracing-subscriber",
+]
+
+[[package]]
 name = "unicode-bidi"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1683,11 +1959,11 @@ dependencies = [
 
 [[package]]
 name = "unicode-normalization"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5479532badd04e128284890390c1e876ef7a993d0570b3597ae43dfa1d59afa4"
+checksum = "6fb19cf769fa8c6a80a162df694621ebeb4dafb606470b2b2fce0be40a98a977"
 dependencies = [
- "smallvec",
+ "tinyvec",
 ]
 
 [[package]]
@@ -1698,9 +1974,9 @@ checksum = "e83e153d1053cbb5a118eeff7fd5be06ed99153f00dbcd8ae310c5fb2b22edc0"
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
+checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
 
 [[package]]
 name = "url"
@@ -1715,13 +1991,37 @@ dependencies = [
 ]
 
 [[package]]
+name = "vfs"
+version = "0.1.0"
+dependencies = [
+ "fst",
+ "paths",
+ "rustc-hash",
+]
+
+[[package]]
+name = "vfs-notify"
+version = "0.1.0"
+dependencies = [
+ "crossbeam-channel",
+ "globset",
+ "jod-thread",
+ "log",
+ "notify",
+ "paths",
+ "rustc-hash",
+ "vfs",
+ "walkdir",
+]
+
+[[package]]
 name = "walkdir"
 version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "777182bc735b6424e1a57516d35ed72cb8019d85c8c9bf536dccb3445c1a2f7d"
 dependencies = [
  "same-file",
- "winapi 0.3.8",
+ "winapi 0.3.9",
  "winapi-util",
 ]
 
@@ -1739,9 +2039,9 @@ checksum = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 
 [[package]]
 name = "winapi"
-version = "0.3.8"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
 dependencies = [
  "winapi-i686-pc-windows-gnu",
  "winapi-x86_64-pc-windows-gnu",
@@ -1765,7 +2065,7 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
 dependencies = [
- "winapi 0.3.8",
+ "winapi 0.3.9",
 ]
 
 [[package]]
@@ -1789,6 +2089,7 @@ name = "xtask"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "flate2",
  "pico-args",
  "proc-macro2",
  "quote",
@@ -1797,9 +2098,9 @@ dependencies = [
 
 [[package]]
 name = "yaml-rust"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65923dd1784f44da1d2c3dbbc5e822045628c590ba72123e1c73d3c230c4434d"
+checksum = "39f0c922f1a334134dc2f7a8b67dc5d25f0735263feec974345ff706bcf20b0d"
 dependencies = [
  "linked-hash-map",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 5278b5a16..612e6809f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,9 +24,16 @@ opt-level = 0
 opt-level = 0
 [profile.release.package.salsa-macros]
 opt-level = 0
+[profile.release.package.tracing-attributes]
+opt-level = 0
 [profile.release.package.xtask]
 opt-level = 0
 
+# Gzipping the artifacts is up to 10 times faster with optimizations (`cargo xtask dist`).
+# `miniz_oxide` is the direct dependency of `flate2` which does all the heavy lifting
+[profile.dev.package.miniz_oxide]
+opt-level = 3
+
 [patch.'crates-io']
 # rowan = { path = "../rowan" }
 
diff --git a/README.md b/README.md
index 1e7c3e9b4..7ba705e73 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ Work on rust-analyzer is sponsored by
 
 [<img src="https://user-images.githubusercontent.com/1711539/58105231-cf306900-7bee-11e9-83d8-9f1102e59d29.png" alt="Ferrous Systems" width="300">](https://ferrous-systems.com/)
 - [Mozilla](https://www.mozilla.org/en-US/)
+- [Embark Studios](https://embark-studios.com/)
 - [freiheit.com](https://www.freiheit.com)
 
 ## Quick Start
diff --git a/crates/expect/Cargo.toml b/crates/expect/Cargo.toml
new file mode 100644
index 000000000..77775630d
--- /dev/null
+++ b/crates/expect/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "expect"
+version = "0.1.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+license = "MIT OR Apache-2.0"
+
+[lib]
+doctest = false
+
+[dependencies]
+once_cell = "1"
+difference = "2"
+stdx = { path = "../stdx" }
diff --git a/crates/expect/src/lib.rs b/crates/expect/src/lib.rs
new file mode 100644
index 000000000..21a458d47
--- /dev/null
+++ b/crates/expect/src/lib.rs
@@ -0,0 +1,356 @@
+//! Snapshot testing library, see
+//! https://github.com/rust-analyzer/rust-analyzer/pull/5101
+use std::{
+    collections::HashMap,
+    env, fmt, fs, mem,
+    ops::Range,
+    panic,
+    path::{Path, PathBuf},
+    sync::Mutex,
+};
+
+use difference::Changeset;
+use once_cell::sync::Lazy;
+use stdx::{lines_with_ends, trim_indent};
+
+const HELP: &str = "
+You can update all `expect![[]]` tests by running:
+
+    env UPDATE_EXPECT=1 cargo test
+
+To update a single test, place the cursor on `expect` token and use `run` feature of rust-analyzer.
+";
+
+fn update_expect() -> bool {
+    env::var("UPDATE_EXPECT").is_ok()
+}
+
+/// expect![[r#"inline snapshot"#]]
+#[macro_export]
+macro_rules! expect {
+    [[$data:literal]] => {$crate::Expect {
+        position: $crate::Position {
+            file: file!(),
+            line: line!(),
+            column: column!(),
+        },
+        data: $data,
+    }};
+    [[]] => { $crate::expect![[""]] };
+}
+
+/// expect_file!["/crates/foo/test_data/bar.html"]
+#[macro_export]
+macro_rules! expect_file {
+    [$path:expr] => {$crate::ExpectFile {
+        path: std::path::PathBuf::from($path)
+    }};
+}
+
+#[derive(Debug)]
+pub struct Expect {
+    pub position: Position,
+    pub data: &'static str,
+}
+
+#[derive(Debug)]
+pub struct ExpectFile {
+    pub path: PathBuf,
+}
+
+#[derive(Debug)]
+pub struct Position {
+    pub file: &'static str,
+    pub line: u32,
+    pub column: u32,
+}
+
+impl fmt::Display for Position {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}:{}:{}", self.file, self.line, self.column)
+    }
+}
+
+impl Expect {
+    pub fn assert_eq(&self, actual: &str) {
+        let trimmed = self.trimmed();
+        if &trimmed == actual {
+            return;
+        }
+        Runtime::fail_expect(self, &trimmed, actual);
+    }
+    pub fn assert_debug_eq(&self, actual: &impl fmt::Debug) {
+        let actual = format!("{:#?}\n", actual);
+        self.assert_eq(&actual)
+    }
+
+    fn trimmed(&self) -> String {
+        if !self.data.contains('\n') {
+            return self.data.to_string();
+        }
+        trim_indent(self.data)
+    }
+
+    fn locate(&self, file: &str) -> Location {
+        let mut target_line = None;
+        let mut line_start = 0;
+        for (i, line) in lines_with_ends(file).enumerate() {
+            if i == self.position.line as usize - 1 {
+                let pat = "expect![[";
+                let offset = line.find(pat).unwrap();
+                let literal_start = line_start + offset + pat.len();
+                let indent = line.chars().take_while(|&it| it == ' ').count();
+                target_line = Some((literal_start, indent));
+                break;
+            }
+            line_start += line.len();
+        }
+        let (literal_start, line_indent) = target_line.unwrap();
+        let literal_length =
+            file[literal_start..].find("]]").expect("Couldn't find matching `]]` for `expect![[`.");
+        let literal_range = literal_start..literal_start + literal_length;
+        Location { line_indent, literal_range }
+    }
+}
+
+impl ExpectFile {
+    pub fn assert_eq(&self, actual: &str) {
+        let expected = self.read();
+        if actual == expected {
+            return;
+        }
+        Runtime::fail_file(self, &expected, actual);
+    }
+    pub fn assert_debug_eq(&self, actual: &impl fmt::Debug) {
+        let actual = format!("{:#?}\n", actual);
+        self.assert_eq(&actual)
+    }
+    fn read(&self) -> String {
+        fs::read_to_string(self.abs_path()).unwrap_or_default().replace("\r\n", "\n")
+    }
+    fn write(&self, contents: &str) {
+        fs::write(self.abs_path(), contents).unwrap()
+    }
+    fn abs_path(&self) -> PathBuf {
+        WORKSPACE_ROOT.join(&self.path)
+    }
+}
+
+#[derive(Default)]
+struct Runtime {
+    help_printed: bool,
+    per_file: HashMap<&'static str, FileRuntime>,
+}
+static RT: Lazy<Mutex<Runtime>> = Lazy::new(Default::default);
+
+impl Runtime {
+    fn fail_expect(expect: &Expect, expected: &str, actual: &str) {
+        let mut rt = RT.lock().unwrap_or_else(|poisoned| poisoned.into_inner());
+        if update_expect() {
+            println!("\x1b[1m\x1b[92mupdating\x1b[0m: {}", expect.position);
+            rt.per_file
+                .entry(expect.position.file)
+                .or_insert_with(|| FileRuntime::new(expect))
+                .update(expect, actual);
+            return;
+        }
+        rt.panic(expect.position.to_string(), expected, actual);
+    }
+
+    fn fail_file(expect: &ExpectFile, expected: &str, actual: &str) {
+        let mut rt = RT.lock().unwrap_or_else(|poisoned| poisoned.into_inner());
+        if update_expect() {
+            println!("\x1b[1m\x1b[92mupdating\x1b[0m: {}", expect.path.display());
+            expect.write(actual);
+            return;
+        }
+        rt.panic(expect.path.display().to_string(), expected, actual);
+    }
+
+    fn panic(&mut self, position: String, expected: &str, actual: &str) {
+        let print_help = !mem::replace(&mut self.help_printed, true);
+        let help = if print_help { HELP } else { "" };
+
+        let diff = Changeset::new(actual, expected, "\n");
+
+        println!(
+            "\n
+\x1b[1m\x1b[91merror\x1b[97m: expect test failed\x1b[0m
+   \x1b[1m\x1b[34m-->\x1b[0m {}
+{}
+\x1b[1mExpect\x1b[0m:
+----
+{}
+----
+
+\x1b[1mActual\x1b[0m:
+----
+{}
+----
+
+\x1b[1mDiff\x1b[0m:
+----
+{}
+----
+",
+            position, help, expected, actual, diff
+        );
+        // Use resume_unwind instead of panic!() to prevent a backtrace, which is unnecessary noise.
+        panic::resume_unwind(Box::new(()));
+    }
+}
+
+struct FileRuntime {
+    path: PathBuf,
+    original_text: String,
+    patchwork: Patchwork,
+}
+
+impl FileRuntime {
+    fn new(expect: &Expect) -> FileRuntime {
+        let path = WORKSPACE_ROOT.join(expect.position.file);
+        let original_text = fs::read_to_string(&path).unwrap();
+        let patchwork = Patchwork::new(original_text.clone());
+        FileRuntime { path, original_text, patchwork }
+    }
+    fn update(&mut self, expect: &Expect, actual: &str) {
+        let loc = expect.locate(&self.original_text);
+        let patch = format_patch(loc.line_indent.clone(), actual);
+        self.patchwork.patch(loc.literal_range, &patch);
+        fs::write(&self.path, &self.patchwork.text).unwrap()
+    }
+}
+
+#[derive(Debug)]
+struct Location {
+    line_indent: usize,
+    literal_range: Range<usize>,
+}
+
+#[derive(Debug)]
+struct Patchwork {
+    text: String,
+    indels: Vec<(Range<usize>, usize)>,
+}
+
+impl Patchwork {
+    fn new(text: String) -> Patchwork {
+        Patchwork { text, indels: Vec::new() }
+    }
+    fn patch(&mut self, mut range: Range<usize>, patch: &str) {
+        self.indels.push((range.clone(), patch.len()));
+        self.indels.sort_by_key(|(delete, _insert)| delete.start);
+
+        let (delete, insert) = self
+            .indels
+            .iter()
+            .take_while(|(delete, _)| delete.start < range.start)
+            .map(|(delete, insert)| (delete.end - delete.start, insert))
+            .fold((0usize, 0usize), |(x1, y1), (x2, y2)| (x1 + x2, y1 + y2));
+
+        for pos in &mut [&mut range.start, &mut range.end] {
+            **pos -= delete;
+            **pos += insert;
+        }
+
+        self.text.replace_range(range, &patch);
+    }
+}
+
+fn format_patch(line_indent: usize, patch: &str) -> String {
+    let mut max_hashes = 0;
+    let mut cur_hashes = 0;
+    for byte in patch.bytes() {
+        if byte != b'#' {
+            cur_hashes = 0;
+            continue;
+        }
+        cur_hashes += 1;
+        max_hashes = max_hashes.max(cur_hashes);
+    }
+    let hashes = &"#".repeat(max_hashes + 1);
+    let indent = &" ".repeat(line_indent);
+    let is_multiline = patch.contains('\n');
+
+    let mut buf = String::new();
+    buf.push('r');
+    buf.push_str(hashes);
+    buf.push('"');
+    if is_multiline {
+        buf.push('\n');
+    }
+    let mut final_newline = false;
+    for line in lines_with_ends(patch) {
+        if is_multiline && !line.trim().is_empty() {
+            buf.push_str(indent);
+            buf.push_str("    ");
+        }
+        buf.push_str(line);
+        final_newline = line.ends_with('\n');
+    }
+    if final_newline {
+        buf.push_str(indent);
+    }
+    buf.push('"');
+    buf.push_str(hashes);
+    buf
+}
+
+static WORKSPACE_ROOT: Lazy<PathBuf> = Lazy::new(|| {
+    let my_manifest =
+        env::var("CARGO_MANIFEST_DIR").unwrap_or_else(|_| env!("CARGO_MANIFEST_DIR").to_owned());
+    // Heuristic, see https://github.com/rust-lang/cargo/issues/3946
+    Path::new(&my_manifest)
+        .ancestors()
+        .filter(|it| it.join("Cargo.toml").exists())
+        .last()
+        .unwrap()
+        .to_path_buf()
+});
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_format_patch() {
+        let patch = format_patch(0, "hello\nworld\n");
+        expect![[r##"
+            r#"
+                hello
+                world
+            "#"##]]
+        .assert_eq(&patch);
+
+        let patch = format_patch(4, "single line");
+        expect![[r##"r#"single line"#"##]].assert_eq(&patch);
+    }
+
+    #[test]
+    fn test_patchwork() {
+        let mut patchwork = Patchwork::new("one two three".to_string());
+        patchwork.patch(4..7, "zwei");
+        patchwork.patch(0..3, "один");
+        patchwork.patch(8..13, "3");
+        expect![[r#"
+            Patchwork {
+                text: "один zwei 3",
+                indels: [
+                    (
+                        0..3,
+                        8,
+                    ),
+                    (
+                        4..7,
+                        4,
+                    ),
+                    (
+                        8..13,
+                        1,
+                    ),
+                ],
+            }
+        "#]]
+        .assert_debug_eq(&patchwork);
+    }
+}
diff --git a/crates/ra_flycheck/Cargo.toml b/crates/flycheck/Cargo.toml
index 1aa39bade..bea485694 100644
--- a/crates/ra_flycheck/Cargo.toml
+++ b/crates/flycheck/Cargo.toml
@@ -1,8 +1,9 @@
 [package]
 edition = "2018"
-name = "ra_flycheck"
+name = "flycheck"
 version = "0.1.0"
 authors = ["rust-analyzer developers"]
+license = "MIT OR Apache-2.0"
 
 [lib]
 doctest = false
diff --git a/crates/flycheck/src/lib.rs b/crates/flycheck/src/lib.rs
new file mode 100644
index 000000000..6804d9bda
--- /dev/null
+++ b/crates/flycheck/src/lib.rs
@@ -0,0 +1,317 @@
+//! cargo_check provides the functionality needed to run `cargo check` or
+//! another compatible command (f.x. clippy) in a background thread and provide
+//! LSP diagnostics based on the output of the command.
+
+use std::{
+    fmt,
+    io::{self, BufReader},
+    ops,
+    path::PathBuf,
+    process::{self, Command, Stdio},
+    time::Duration,
+};
+
+use crossbeam_channel::{never, select, unbounded, Receiver, Sender};
+
+pub use cargo_metadata::diagnostic::{
+    Applicability, Diagnostic, DiagnosticCode, DiagnosticLevel, DiagnosticSpan,
+    DiagnosticSpanMacroExpansion,
+};
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum FlycheckConfig {
+    CargoCommand {
+        command: String,
+        all_targets: bool,
+        all_features: bool,
+        features: Vec<String>,
+        extra_args: Vec<String>,
+    },
+    CustomCommand {
+        command: String,
+        args: Vec<String>,
+    },
+}
+
+impl fmt::Display for FlycheckConfig {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            FlycheckConfig::CargoCommand { command, .. } => write!(f, "cargo {}", command),
+            FlycheckConfig::CustomCommand { command, args } => {
+                write!(f, "{} {}", command, args.join(" "))
+            }
+        }
+    }
+}
+
+/// Flycheck wraps the shared state and communication machinery used for
+/// running `cargo check` (or other compatible command) and providing
+/// diagnostics based on the output.
+/// The spawned thread is shut down when this struct is dropped.
+#[derive(Debug)]
+pub struct FlycheckHandle {
+    // XXX: drop order is significant
+    sender: Sender<Restart>,
+    thread: jod_thread::JoinHandle,
+}
+
+impl FlycheckHandle {
+    pub fn spawn(
+        sender: Box<dyn Fn(Message) + Send>,
+        config: FlycheckConfig,
+        workspace_root: PathBuf,
+    ) -> FlycheckHandle {
+        let actor = FlycheckActor::new(sender, config, workspace_root);
+        let (sender, receiver) = unbounded::<Restart>();
+        let thread = jod_thread::spawn(move || actor.run(receiver));
+        FlycheckHandle { sender, thread }
+    }
+
+    /// Schedule a re-start of the cargo check worker.
+    pub fn update(&self) {
+        self.sender.send(Restart).unwrap();
+    }
+}
+
+#[derive(Debug)]
+pub enum Message {
+    /// Request adding a diagnostic with fixes included to a file
+    AddDiagnostic { workspace_root: PathBuf, diagnostic: Diagnostic },
+
+    /// Request check progress notification to client
+    Progress(Progress),
+}
+
+#[derive(Debug)]
+pub enum Progress {
+    DidStart,
+    DidCheckCrate(String),
+    DidFinish(io::Result<()>),
+    DidCancel,
+}
+
+struct Restart;
+
+struct FlycheckActor {
+    sender: Box<dyn Fn(Message) + Send>,
+    config: FlycheckConfig,
+    workspace_root: PathBuf,
+    /// WatchThread exists to wrap around the communication needed to be able to
+    /// run `cargo check` without blocking. Currently the Rust standard library
+    /// doesn't provide a way to read sub-process output without blocking, so we
+    /// have to wrap sub-processes output handling in a thread and pass messages
+    /// back over a channel.
+    cargo_handle: Option<CargoHandle>,
+}
+
+enum Event {
+    Restart(Restart),
+    CheckEvent(Option<cargo_metadata::Message>),
+}
+
+impl FlycheckActor {
+    fn new(
+        sender: Box<dyn Fn(Message) + Send>,
+        config: FlycheckConfig,
+        workspace_root: PathBuf,
+    ) -> FlycheckActor {
+        FlycheckActor { sender, config, workspace_root, cargo_handle: None }
+    }
+    fn next_event(&self, inbox: &Receiver<Restart>) -> Option<Event> {
+        let check_chan = self.cargo_handle.as_ref().map(|cargo| &cargo.receiver);
+        select! {
+            recv(inbox) -> msg => msg.ok().map(Event::Restart),
+            recv(check_chan.unwrap_or(&never())) -> msg => Some(Event::CheckEvent(msg.ok())),
+        }
+    }
+    fn run(mut self, inbox: Receiver<Restart>) {
+        while let Some(event) = self.next_event(&inbox) {
+            match event {
+                Event::Restart(Restart) => {
+                    while let Ok(Restart) = inbox.recv_timeout(Duration::from_millis(50)) {}
+
+                    self.cancel_check_process();
+
+                    let mut command = self.check_command();
+                    log::info!("restart flycheck {:?}", command);
+                    command.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
+                    if let Ok(child) = command.spawn().map(JodChild) {
+                        self.cargo_handle = Some(CargoHandle::spawn(child));
+                        self.send(Message::Progress(Progress::DidStart));
+                    }
+                }
+                Event::CheckEvent(None) => {
+                    // Watcher finished, replace it with a never channel to
+                    // avoid busy-waiting.
+                    let cargo_handle = self.cargo_handle.take().unwrap();
+                    let res = cargo_handle.join();
+                    self.send(Message::Progress(Progress::DidFinish(res)));
+                }
+                Event::CheckEvent(Some(message)) => match message {
+                    cargo_metadata::Message::CompilerArtifact(msg) => {
+                        self.send(Message::Progress(Progress::DidCheckCrate(msg.target.name)));
+                    }
+
+                    cargo_metadata::Message::CompilerMessage(msg) => {
+                        self.send(Message::AddDiagnostic {
+                            workspace_root: self.workspace_root.clone(),
+                            diagnostic: msg.message,
+                        });
+                    }
+
+                    cargo_metadata::Message::BuildScriptExecuted(_)