Remove unstable parts

This commit removes unstable features that nobody is working on at the moment: - completions and signature help with the presentation compiler. - diagnostics as you type with the presentation compiler. - hover with an old scalafix type printer. This will be replaced with one of the newer type printers that is based on the new symbol tables. - linting with Scalafix, the integration uses an old internal API. Scalafix now has a public API for build tools that we should hook into instead. Refactoring to use the new API is equivalent to a full rewrite so we may as well remove the current integration. This commit also updates the project overview to reflect the current status.
scalameta · Oct 1, 2018 · b84fa44 · b84fa44
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diff --git a/.travis.yml b/.travis.yml
@@ -19,7 +19,7 @@ jobs:
       script:
         - ./bin/run-scripted.sh
     - stage: release
-      script: sbt ci-release
+      script: sbt ci-release docs/docusaurusPublishGhpages
 
 cache:
   directories:

diff --git a/build.sbt b/build.sbt
@@ -166,12 +166,12 @@ lazy val docs = project
       sourceDirectory.in(metals, Compile).value /
         "scala/scala/meta/metals/Configuration.scala"
     },
-    scalaVersion := "2.12.6",
+    scalaVersion := "2.12.7",
     crossScalaVersions := List("2.12.6"),
     mainClass.in(Compile) := Some("docs.Docs"),
     SettingKey[Boolean]("metalsEnabled") := false,
     libraryDependencies ++= List(
-      "com.geirsson" % "mdoc" % "0.4.5" cross CrossVersion.full,
+      "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,

diff --git a/docs/overview.md b/docs/overview.md
@@ -3,60 +3,36 @@ id: overview
 title: Overview
 ---
 
-This document is an overview of the Metals project. Metals is a community driven
-project with no official funding or dedicated resources.
+This document describes the project goals of Metals. This document does not
+describe existing functionality of Metals but rather what user experience we
+want Metals to have in the future.
 
-* [**Simple installation**](#simple-installation): importing a project should be
+- [**Simple installation**](#simple-installation): importing a project should be
   simple and require as few steps as possible.
-* [**Correct diagnostics**](#correct-diagnostics): the editor should not show
-  spurious red squiggles, even at the cost of higher latency.
-* [**Robust navigation**](#robust-navigation): goto definition should work
+- [**Robust navigation**](#robust-navigation): goto definition should work
   everywhere, even for Java dependencies.
-* [**Fast completions**](#fast-completions): completions suggestions should
-  respond in ~200ms, even at the cost of occasionally wrong results.
-* [**Low CPU and memory usage**](#low-cpu-and-memory-usage): indexing should run
+- [**Low CPU and memory usage**](#low-cpu-and-memory-usage): indexing should run
   in the background and not get in your way from coding.
-* [**Solid refactoring**](#solid-refactoring): rename, organize imports and
-  insert type annotation should always leave the codebase in a compiling state.
+
+We acknowledge that simple installation and robust navigation alone is not
+enough to make a great language server. A great language server should also
+support correct diagnostics, fast completions and solid refactorings. However,
+we believe navigation is an important first milestone that needs full attention
+before working on other features.
 
 ## Simple installation
 
 The first you do with an IDE is boring but critical: import a project. The
 Language Server Protocol does not provide utilities to extract metadata from a
-build tool (module source files, dependencies, configuration data), so we are
-still exploring what is the best option.
-
-* [x] sbt-metals: plugin that provides a `metalsSetup` task to export sbt
-    build metadata.
-
-* [ ] [BSP][]: LSP-inspired protocol to standardize on communication between a
-  language server and build tool. In theory, should enable automatic
-  importing of projects without custom build plugins or manual installation
-  steps.
-
-## Correct diagnostics
-
-Red squiggles are one of the most basic but also difficult-to-support features
-in an IDE. The Scala compiler was not designed for interactivity, which makes
-fast and correct diagnostics difficult to support in the editor. We are still
-unsure what the best model is for diagnostics, so we are still exploring what is
-the best option.
-
-* [x] Scala Presentation Compiler: interactively publish squiggles as you type.
-      Provides low latency but may get off-sync with build diagnostics.
-  * Disabled by default. Can be enabled with configuration option
-    `scalac.diagnostics.enabled=true`.
-  * Requires [`metalsSetup`](#metalssetup).
-* [x] sbt server: sbt 1.1 added LSP support so that build errors are reported
-      directly to the editor. Metals can connect to sbt server as a client to
-      trigger batch compilation on file save. Guarantees diagnostics are always
-      in-sync with build diagnostics but at the cost of higher latency.
-  * Disabled by default. Can be enabled with configuration option
-    `sbt.enabled=true`.
-  * Requires a running sbt 1.1 server or later.
-* [x] Linting with [Scalafix][].
-  * Requires [semanticdb-scalac](#semanticdb-scalac).
-  * Supports both built-in and custom linter rules.
+build tool (source directories, dependencies, compiler flags) so we are still
+exploring what is the best option.
+
+- [x] sbt-metals: plugin that provides a `metalsSetup` task to export sbt build
+      metadata.
+- [ ] [BSP][]: LSP-inspired protocol to standardize on communication between a
+      language server and build tool. In theory, should enable automatic
+      importing of projects without custom build plugins or manual installation
+      steps.
 
 ## Robust navigation
 
@@ -66,113 +42,45 @@ about programs in Scala and other languages, to power code navigation. Indexing
 happens with during batch compilation in the build tool, using a similar
 architecture as [Index-While-Building][] in XCode 9.
 
-* Goto definition (`textDocument/definition`). Requires
+- Goto definition (`textDocument/definition`). Requires
   [semanticdb-scalac](#semanticdb-scalac).
-
   - [x] project -> project.
-
   - [x] project -> Scala dependency. Requires [`metalsSetup`](#metalssetup).
-
   - [x] project -> Java dependency. Requires [`metalsSetup`](#metalssetup).
-
   - [ ] dependency -> dependency.
-
-* [x] Find references (`textDocument/references`). Works the same as goto
+- [x] Find references (`textDocument/references`). Works the same as goto
       definition.
-
   - [x] project references
-
   - [ ] Scala dependency references
-
   - [ ] Java dependency references
-
-* [x] Highlight references to symbol at position
+- [x] Highlight references to symbol at position
       (`textDocument/documentHighlight`).
-
-  * Disabled by default. Can be enabled with configuration option
+  - Disabled by default. Can be enabled with configuration option
     `highlight.enabled=true`.
-
-* [x] Goto symbol in file (`textDocument/documentSymbol`)
-
-* [x] Goto symbol in workspace (`workspace/symbol`)
-
-* [x] Symbol outline in the sidebar as you type (`textDocument/documentSymbol`).
-
-* [ ] Goto implementation (`textDocument/implementation`)
-
-* [ ] Goto type definition (`textDocument/typeDefinition`)
-
-* [x] Show type of symbol at position (`textDocument/hover`). Requires
-      [semanticdb-scalac](#semanticdb-scalac).
-
-* [ ] Show type of expression at position (`textDocument/hover`).
-
-## Fast completions
-
-Auto completions are a great way to explore a library interface and save
-keystrokes while writing code. Completions are sensitive to latency since
-suggestions update on every keystroke. Correct and fast completions are
-difficult to support in Scala due to several challenges:
-
-1.  the presentation compiler does not lend itself well to interactive editing
-2.  some completions semantics are difficult to reproduce outside of the
-    compiler
-    * extension methods depend on implicit conversions
-    * whitebox macros can refine result types which influences completion
-      suggestions
-
-Given these challenges, we are still exploring how to best support correct and
-fast completions.
-
-* [x] Scala Presentation Compiler. Faithfully reproduces full language semantics
-      but may be slow and difficult to keep in-sync with the build for
-      long-running interactive sessions.
-  * Disabled by default. Can be enabled with configuration option
-    `scalac.completions.enabled=true`.
-  * Requires [`metalsSetup`](#metalssetup).
-  * Shows parameter list as you type (`textDocument/signatureHelp`).
-* [ ] Auto-import global symbol from classpath.
-* [ ] Auto-expand abstract methods when implementing a trait or abstract class.
+- [x] Goto symbol in file (`textDocument/documentSymbol`)
+- [x] Goto symbol in workspace (`workspace/symbol`)
+- [x] Symbol outline in the sidebar as you type (`textDocument/documentSymbol`).
+- [ ] Goto implementation (`textDocument/implementation`)
+- [ ] Goto type definition (`textDocument/typeDefinition`)
+- [ ] Show type of symbol at position (`textDocument/hover`).
+- [ ] Show type of expression at position (`textDocument/hover`).
 
 ## Low CPU and memory usage
 
 Heavy resource usage is one of the most frequent complaints about IDEs. Low CPU
 and memory usage becomes even more important when working in larger codebases.
 
-* [ ] Persistent symbol index: currently Metals stores the navigation index
+- [ ] Persistent symbol index: currently Metals stores the navigation index
       in-memory, which can consume multiple GB of RAM for large projects.
-* [ ] Faster Scala and Java outline indexing. Currently, Metals can index the
+- [ ] Faster Scala and Java outline indexing. Currently, Metals can index the
       outlines of Scala sources at ~30-40k loc/s and Java sources at ~450k
       loc/s. Indexing should be able to process ~500k loc/s.
-* [ ] Throttled background indexing. Currently, all available CPUs are utilized
+- [ ] Throttled background indexing. Currently, all available CPUs are utilized
       for indexing, which makes the computer slow for a period after running
       `metalsSetup`.
-* [ ] Faster "open symbol in workspace" (`workspace/symbol`). Currently, uses a
+- [ ] Faster "open symbol in workspace" (`workspace/symbol`). Currently, uses a
       naive linear search algorithm that is slow for large projects.
 
-## Solid refactoring
-
-Refactoring makes you more productive while editing code. On demand refactoring
-such as rename or formatting are great to save keystrokes for frequent
-mechanical tasks. Passive refactoring suggestions help you learn new language
-best practices.
-
-* Format (`textDocument/formatting`) with [Scalafmt][].
-  * [x] Whole file on demand (`textDocument/formatting`)
-  * [ ] Selected range (`textDocument/rangeFormatting`)
-  * [x] On save (`textDocument/willSaveWaitUntil`)
-  * [ ] As you type (`textDocument/onTypeFormatting`)
-  * Scalafmt version can be configured with `scalafmt.version="1.3.0"`.
-  * NOTE. The first time Scalafmt is invoked is slow since it requires
-    downloading the configured Scalafmt version with Coursier.
-* [x] Rename local symbol. Requires [semanticdb-scalac](#semanticdb-scalac).
-* [ ] Rename global symbol.
-* [x] Remove unused imports (`textDocument/codeActions`). Requires
-      [semanticdb-scalac](#semanticdb-scalac).
-* [ ] Move class.
-* [ ] Organize imports.
-* [ ] Insert type annotation.
-
 ## Glossary
 
 ### metalsSetup
@@ -186,9 +94,11 @@ Compiler plugin that emits [SemanticDB][] files during batch compilation in the
 build tool. Overhead of the compiler plugin is ~30%, which may improve in the
 future.
 
-[semanticdb]: https://github.com/scalameta/scalameta/blob/master/semanticdb/semanticdb3/semanticdb3.md
+[semanticdb]:
+  https://github.com/scalameta/scalameta/blob/master/semanticdb/semanticdb3/semanticdb3.md
 [index-while-building]: https://youtu.be/jGJhnIT-D2M
-[code outline]: https://marketplace.visualstudio.com/items?itemName=patrys.vscode-code-outline
+[code outline]:
+  https://marketplace.visualstudio.com/items?itemName=patrys.vscode-code-outline
 [atom-ide-ui]: https://atom.io/packages/atom-ide-ui
 [bsp]: https://github.com/scalacenter/bsp/blob/master/docs/bsp.md
 [scalafmt]: http://scalafmt.org/

diff --git a/metals/src/main/scala/scala/meta/metals/Effects.scala b/metals/src/main/scala/scala/meta/metals/Effects.scala
@@ -13,10 +13,6 @@ object Effects {
   final val IndexSemanticdb = new IndexSemanticdb
   final class IndexSourcesClasspath extends Effects
   final val IndexSourcesClasspath = new IndexSourcesClasspath
-  final class InstallPresentationCompiler extends Effects
-  final val InstallPresentationCompiler = new InstallPresentationCompiler
-  final class PublishDiagnostics extends Effects
-  final val PublishDiagnostics = new PublishDiagnostics
   final class UpdateBuffers extends Effects
   final val UpdateBuffers = new UpdateBuffers
 }
diff --git a/metals/src/main/scala/scala/meta/metals/Linter.scala b/metals/src/main/scala/scala/meta/metals/Linter.scala