Implement goto definition with low CPU and memory overhead

.scalafix.conf

@@ -0,0 +1,3 @@
+rules = [
+  RemoveUnused
+]

.scalafmt.conf

@@ -12,5 +12,6 @@ To fix this problem:
 
 project.excludeFilters = [
   test-workspace
+  tests/unit/src/test/resources
   sbt-metals/src/sbt-test
 ]

.travis.yml

@@ -10,8 +10,10 @@ stages:
 jobs:
   include:
     # default stage is test
-    - env: TEST="scalafmt"
-      script: ./bin/scalafmt --test
+    - env: TEST="scalafmt+scalafix"
+      script:
+        - ./bin/scalafmt --test
+        - sbt scalafixCheck
     - env: TEST="sbt test"
       script:
         - sbt startServer metalsSetup test

build.sbt

@@ -1,22 +1,24 @@
+import java.io.File
 inThisBuild(
   List(
     version ~= { dynVer =>
       if (sys.env.contains("CI")) dynVer
       else "SNAPSHOT" // only for local publishng
     },
+    scalaVersion := V.scala212,
+    crossScalaVersions := List(V.scala212),
     scalacOptions ++= List(
       "-Yrangepos",
       "-deprecation",
       // -Xlint is unusable because of
       // https://github.com/scala/bug/issues/10448
       "-Ywarn-unused-import"
     ),
+    addCompilerPlugin(MetalsPlugin.semanticdbScalac),
     organization := "org.scalameta",
     licenses := Seq(
       "Apache-2.0" -> url("http://www.apache.org/licenses/LICENSE-2.0")
     ),
-    testFrameworks := List(new TestFramework("utest.runner.Framework")),
-    libraryDependencies += "com.lihaoyi" %% "utest" % "0.6.0" % Test,
     homepage := Some(url("https://github.com/scalameta/metals")),
     developers := List(
       Developer(
@@ -50,70 +52,49 @@ inThisBuild(
         url("http://delmore.io")
       )
     ),
+    testFrameworks := List(),
     resolvers += Resolver.sonatypeRepo("releases"),
     // faster publishLocal:
     publishArtifact in packageDoc := sys.env.contains("CI"),
-    publishArtifact in packageSrc := sys.env.contains("CI"),
-    addCompilerPlugin(
-      "org.scalamacros" % "paradise" % "2.1.0" cross CrossVersion.full
-    )
+    publishArtifact in packageSrc := sys.env.contains("CI")
   )
 )
 
+addCommandAlias("scalafixAll", "all compile:scalafix test:scalafix")
+addCommandAlias("scalafixCheck", "; scalafix --check ; test:scalafix --check")
+
+commands += Command.command("save-expect") { s =>
+  "unit/test:runMain tests.SaveExpect" ::
+    s
+}
+
 lazy val V = new {
   val scala210 = "2.10.7"
   val scala212 = MetalsPlugin.scala212
   val scalameta = MetalsPlugin.semanticdbVersion
-  val scalafix = "0.5.7"
-  val circe = "0.9.0"
-  val enumeratum = "1.5.12"
 }
 
-lazy val legacyScala212 = List(
-  addCompilerPlugin(MetalsPlugin.semanticdbScalac),
-  scalaVersion := V.scala212,
-  crossScalaVersions := List(V.scala212),
-)
+skip.in(publish) := true
 
-skip in publish := true
-legacyScala212
+lazy val mtags = project
+  .settings(
+    libraryDependencies ++= List(
+      "com.thoughtworks.qdox" % "qdox" % "2.0-M9", // for java mtags
+      "org.scalameta" %% "scalameta" % V.scalameta
+    )
+  )
 
 lazy val metals = project
-  .enablePlugins(BuildInfoPlugin)
   .settings(
-    legacyScala212,
-    fork in Test := true, // required for jni interrop with leveldb.
-    buildInfoKeys := Seq[BuildInfoKey](
-      "testWorkspaceBaseDirectory" ->
-        baseDirectory.in(testWorkspace).value,
-      version,
-    ),
-    buildInfoPackage := "scala.meta.metals.internal",
     libraryDependencies ++= List(
+      "com.thoughtworks.qdox" % "qdox" % "2.0-M9", // for java mtags
       "com.lihaoyi" %% "pprint" % "0.5.3", // for pretty formatting of log values
-      "org.scala-sbt.ipcsocket" % "ipcsocket" % "1.0.0", // for sbt server
-      "ch.epfl.scala" % "scalafix-reflect" % V.scalafix cross CrossVersion.full,
-      "com.googlecode.java-diff-utils" % "diffutils" % "1.3.0", // for edit-distance
-      "com.thoughtworks.qdox" % "qdox" % "2.0-M7", // for java mtags
-      "io.get-coursier" %% "coursier" % coursier.util.Properties.version, // for jars
-      "io.get-coursier" %% "coursier-cache" % coursier.util.Properties.version,
-      "io.github.soc" % "directories" % "5", // for cache location
-      "me.xdrop" % "fuzzywuzzy" % "1.1.9", // for workspace/symbol
-      "org.fusesource.leveldbjni" % "leveldbjni-all" % "1.8", // for caching classpath index
-      "org.scalameta" %% "lsp4s" % "0.2.1",
-      "org.scalameta" %% "semanticdb-scalac" % V.scalameta cross CrossVersion.full,
-      "io.circe" %% "circe-core" % V.circe,
-      "io.circe" %% "circe-generic" % V.circe,
-      "io.circe" %% "circe-generic-extras" % V.circe,
-      "io.circe" %% "circe-parser" % V.circe,
-      "com.beachape" %% "enumeratum" % V.enumeratum,
-      "com.beachape" %% "enumeratum-circe" % "1.5.15",
-      "org.scalameta" %% "testkit" % V.scalameta % Test,
+      "org.scalameta" %% "scalameta" % V.scalameta,
+      "org.scalameta" %% "symtab" % V.scalameta,
+      "org.scalameta" %% "lsp4s" % "0.2.1"
     )
   )
-  .dependsOn(
-    testWorkspace % "test->test"
-  )
+  .dependsOn(mtags)
 
 lazy val `sbt-metals` = project
   .settings(
@@ -135,54 +116,73 @@ lazy val `sbt-metals` = project
     ),
   )
   .enablePlugins(ScriptedPlugin)
+  .disablePlugins(ScalafixPlugin)
 
-lazy val integration = project
-  .in(file("tests/integration"))
+lazy val input = project
+  .in(file("tests/input"))
   .settings(
-    legacyScala212,
-    skip in publish := true
+    skip.in(publish) := true,
+    libraryDependencies ++= List(
+      // these projects have macro annotations
+      "org.scalameta" %% "scalameta" % V.scalameta,
+      "io.circe" %% "circe-derivation-annotations" % "0.9.0-M5"
+    ),
+    addCompilerPlugin(
+      "org.scalamacros" % "paradise" % "2.1.0" cross CrossVersion.full
+    )
   )
-  .dependsOn(metals % "compile->compile;test->test")
 
-lazy val testWorkspace = project
-  .in(file("test-workspace"))
+lazy val unit = project
+  .in(file("tests/unit"))
   .settings(
-    legacyScala212,
-    skip in publish := true,
-    scalacOptions += {
-      // Need to fix source root so it matches the workspace folder.
-      s"-P:semanticdb:sourceroot:${baseDirectory.value}"
-    },
-    scalacOptions += "-Ywarn-unused-import",
-    scalacOptions -= "-Xlint"
+    skip.in(publish) := true,
+    testFrameworks := List(new TestFramework("utest.runner.Framework")),
+    libraryDependencies ++= List(
+      "io.get-coursier" %% "coursier" % coursier.util.Properties.version, // for jars
+      "io.get-coursier" %% "coursier-cache" % coursier.util.Properties.version,
+      "org.scalameta" % "metac" % V.scalameta cross CrossVersion.full,
+      "org.scalameta" %% "testkit" % V.scalameta,
+      "com.lihaoyi" %% "utest" % "0.6.0",
+    ),
+    buildInfoPackage := "tests",
+    resourceGenerators.in(Compile) += InputProperties.resourceGenerator(input),
+    compile.in(Compile) :=
+      compile.in(Compile).dependsOn(compile.in(input, Test)).value,
+    buildInfoKeys := Seq[BuildInfoKey](
+      "testResourceDirectory" -> resourceDirectory.in(Test).value
+    )
   )
+  .dependsOn(metals)
+  .enablePlugins(BuildInfoPlugin)
+
+lazy val bench = project
+  .in(file("metals-bench"))
+  .settings(
+    fork.in(run) := true,
+    skip.in(publish) := true,
+    moduleName := "metals-bench",
+    libraryDependencies ++= List(
+      // for measuring memory usage
+      "org.spire-math" %% "clouseau" % "0.2.2",
+      "org.openjdk.jol" % "jol-core" % "0.9"
+    ),
+  )
+  .dependsOn(unit)
+  .enablePlugins(JmhPlugin)
 
 lazy val docs = project
   .in(file("metals-docs"))
   .settings(
-    skip in publish := true, // disabled until Scalameta v4 upgrade
+    skip.in(publish) := true,
     moduleName := "metals-docs",
-    sources.in(Compile) += {
-      sourceDirectory.in(metals, Compile).value /
-        "scala/scala/meta/metals/Configuration.scala"
-    },
-    scalaVersion := "2.12.7",
-    crossScalaVersions := List("2.12.6"),
     mainClass.in(Compile) := Some("docs.Docs"),
-    SettingKey[Boolean]("metalsEnabled") := false,
     libraryDependencies ++= List(
-      "com.geirsson" % "mdoc" % "0.5.0" cross CrossVersion.full,
-      // Dependencies below can be removed after the upgrade to Scalameta v4.0
-      "io.circe" %% "circe-core" % V.circe,
-      "io.circe" %% "circe-generic" % V.circe,
-      "io.circe" %% "circe-generic-extras" % V.circe,
-      "io.circe" %% "circe-parser" % V.circe,
-      "com.beachape" %% "enumeratum" % V.enumeratum,
-      "com.beachape" %% "enumeratum-circe" % "1.5.15"
+      "com.geirsson" % "mdoc" % "0.5.1" cross CrossVersion.full
     ),
     buildInfoKeys := Seq[BuildInfoKey](
       version,
     ),
     buildInfoPackage := "docs"
   )
+  .dependsOn(metals)
   .enablePlugins(DocusaurusPlugin, BuildInfoPlugin)

docs/installation-contributors.md

@@ -3,17 +3,18 @@ id: installation-contributors
 title: Installation
 ---
 
-> ⚠ ️ This project is very alpha stage. Expect bugs and incomplete documentation.
+> ⚠ ️ This project is very alpha stage. Expect bugs and incomplete
+> documentation.
 
 The following instructions are intended for contributors who want to try Metals
 and provide feedback. We do not provide support for day-to-day usage of Metals.
 
 ## Requirements
 
-* Scala 2.12.4, down to the exact PATCH version. Note that Scala versions 2.11.x and
-  2.12.6 are not supported.
-* Java 8. Note that Java 9 or higher has not been tested.
-* macOS or Linux. Note that there have been reported issues on Windows.
+- Scala @SCALA_VERSION@, down to the exact PATCH version. Note that Scala
+  versions 2.11.x and 2.12.6 are not supported.
+- Java 8. Note that Java 9 or higher has not been tested.
+- macOS or Linux. Note that there have been reported issues on Windows.
 
 ## Global setup
 
@@ -30,57 +31,66 @@ You can install the plugin with:
 addSbtPlugin("org.scalameta" % "sbt-metals" % "@VERSION@")
 ```
 
-You can add the plugin to a specific project (adding it to `project/plugins.sbt`) or globally adding it to:
+You can add the plugin to a specific project (adding it to
+`project/plugins.sbt`) or globally adding it to:
 
 - (sbt 1) `~/.sbt/1.0/plugins/plugins.sbt`
 - (sbt 0.13) `~/.sbt/0.13/plugins/plugins.sbt`
 
 ### VSCode extension
 
-> ***N.B.*** This project is still in development - right now you will need to run the VSCode plugin
-> as described [here](getting-started-contributors.html#running-a-local-version-of-the-vscode-extension)
+> **_N.B._** This project is still in development - right now you will need to
+> run the VSCode plugin as described
+> [here](getting-started-contributors.html#running-a-local-version-of-the-vscode-extension)
 
 ## Per-project setup
 
 These steps are required on each project.
 
 ### Quick-start
-The quickest way to get started with Metals is to use the `metalsSetup` command in sbt.
+
+The quickest way to get started with Metals is to use the `metalsSetup` command
+in sbt.
 
 ```
 sbt
 > metalsSetup
 ```
 
-The command will create the necessary metadata in the `.metals` directory
-(which you should not checkout into version control) and setup the `semanticdb-scalac` compiler
-plugin for the current sbt session.
+The command will create the necessary metadata in the `.metals` directory (which
+you should not checkout into version control) and setup the `semanticdb-scalac`
+compiler plugin for the current sbt session.
 
-You should not checkout the `.metals` directory into version control. We recommend to add it to your
-project's `.gitignore` or/and to your global `.gitignore`:
+You should not checkout the `.metals` directory into version control. We
+recommend to add it to your project's `.gitignore` or/and to your global
+`.gitignore`:
 
 ```
 echo ".metals/" >> .gitignore
 ```
 
-Note that in sbt 0.13 you will need to invoke `metalsSetup` (or `semanticdbEnable`) whenever you close and
-re-open sbt. For a more persistent setup, keep reading. In sbt 1 you don't need to do it because Metals will
-automatically invoke `semanticdbEnable` every time it connects to the sbt server.
+Note that in sbt 0.13 you will need to invoke `metalsSetup` (or
+`semanticdbEnable`) whenever you close and re-open sbt. For a more persistent
+setup, keep reading. In sbt 1 you don't need to do it because Metals will
+automatically invoke `semanticdbEnable` every time it connects to the sbt
+server.
 
 ### Persisting the semanticdb-scalac compiler plugin
-Some features like definition/references/hover rely on artifacts produced by a compiler plugin
-called `semanticdb-scalac`.
 
-`metalsSetup` enables the plugin on the current session (by invoking `semanticdbEnable`), but you
-can choose to enable it permanently on your project by adding these two settings in your sbt build
-definition:
+Some features like definition/references/hover rely on artifacts produced by a
+compiler plugin called `semanticdb-scalac`.
+
+`metalsSetup` enables the plugin on the current session (by invoking
+`semanticdbEnable`), but you can choose to enable it permanently on your project
+by adding these two settings in your sbt build definition:
 
 ```scala
 addCompilerPlugin(MetalsPlugin.semanticdbScalac)
 scalacOptions += "-Yrangepos"
 ```
 
 ### Start editing
+
 Open your project in VSCode (`code .` from your terminal) and open a Scala file;
 the server will now start.