Make ExplicitResultTypes scope aware

build.sbt

@@ -3,10 +3,13 @@ inThisBuild(
   List(
     onLoadMessage := s"Welcome to scalafix ${version.value}",
     scalaVersion := scala212,
-    crossScalaVersions := List(scala212, scala211)
+    crossScalaVersions := List(scala212, scala211),
+    fork.in(Test, test) := true
   )
 )
 
+cancelable.in(Global) := true
+
 noPublish
 
 // force javac to fork by setting javaHome to get error messages during compilation,
@@ -69,7 +72,8 @@ lazy val rules = project
   .in(file("scalafix-rules"))
   .settings(
     moduleName := "scalafix-rules",
-    description := "Built-in Scalafix rules"
+    description := "Built-in Scalafix rules",
+    libraryDependencies += "org.scalameta" % "mtags" % "0.7.6" cross CrossVersion.full
   )
   .dependsOn(core)
 
@@ -93,6 +97,9 @@ lazy val cli = project
     mainClass in assembly := Some("scalafix.v1.Main"),
     assemblyJarName in assembly := "scalafix.jar",
     libraryDependencies ++= Seq(
+      "ch.epfl.scala" %% "bloop-launcher" % "1.3.3",
+      "ch.epfl.scala" % "bsp4j" % "2.0.0-M4+10-61e61e87",
+      "org.scala-lang.modules" %% "scala-java8-compat" % "0.9.0",
       "com.martiansoftware" % "nailgun-server" % "0.9.1",
       jgit,
       "ch.qos.logback" % "logback-classic" % "1.2.3",
@@ -126,6 +133,7 @@ lazy val testsInput = project
     scalacOptions += warnUnusedImports.value, // For RemoveUnused
     scalacOptions += "-Ywarn-unused", // For RemoveUnusedTerms
     logLevel := Level.Error, // avoid flood of compiler warnings
+    libraryDependencies += "com.twitter" %% "bijection-core" % "0.9.5",
     testsInputOutputSetting,
     coverageEnabled := false
   )
@@ -140,7 +148,8 @@ lazy val testsOutput = project
       "-Xlint"
     ),
     testsInputOutputSetting,
-    coverageEnabled := false
+    coverageEnabled := false,
+    libraryDependencies += "com.twitter" %% "bijection-core" % "0.9.5"
   )
 
 lazy val testkit = project
@@ -170,7 +179,8 @@ lazy val unit = project
     libraryDependencies ++= List(
       jgit,
       semanticdbPluginLibrary,
-      scalatest
+      scalatest,
+      "org.scalameta" %% "testkit" % scalametaV
     ),
     compileInputs.in(Compile, compile) := {
       compileInputs

scalafix-cli/src/main/scala/scalafix/internal/interfaces/ScalafixArgumentsImpl.scala

@@ -40,12 +40,13 @@ final case class ScalafixArgumentsImpl(args: Args = Args.default)
   ): ScalafixArguments =
     copy(args = args.copy(toolClasspath = classLoader))
 
-  override def withPaths(paths: util.List[Path]): ScalafixArguments =
+  override def withPaths(paths: util.List[Path]): ScalafixArguments = {
     copy(
       args = args.copy(
         files = paths.asScala.iterator.map(AbsolutePath(_)(args.cwd)).toList
       )
     )
+  }
 
   override def withExcludedPaths(
       matchers: util.List[PathMatcher]

scalafix-cli/src/main/scala/scalafix/internal/v1/Args.scala

@@ -37,6 +37,9 @@ import scalafix.internal.jgit.JGitDiff
 import scalafix.internal.reflect.ClasspathOps
 import scalafix.v1.Configuration
 import scalafix.v1.RuleDecoder
+import scala.tools.nsc.interactive.Global
+import scala.tools.nsc.Settings
+import scala.tools.nsc.reporters.ConsoleReporter
 
 class Section(val name: String) extends StaticAnnotation
 
@@ -257,11 +260,11 @@ case class Args(
   ): Configured[Rules] = {
     val rulesConf = this.rulesConf(() => base)
     val decoder = ruleDecoder(scalafixConfig)
-
     val configuration = Configuration()
       .withConf(base)
       .withScalaVersion(scalaVersion)
       .withScalacOptions(scalacOptions)
+      .withScalacClasspath(classpath.entries)
     decoder.read(rulesConf).andThen(_.withConfiguration(configuration))
   }
 
@@ -348,6 +351,15 @@ case class Args(
     }
   }
 
+  def configuredGlobal: Configured[Option[Global]] =
+    Configured.ok {
+      val settings = new Settings()
+      settings.YpresentationAnyThread.value = true
+      settings.classpath.value = classpath.syntax
+      val reporter = new ConsoleReporter(settings)
+      Some(new Global(settings, reporter))
+    }
+
   def validate: Configured[ValidatedArgs] = {
     baseConfig.andThen {
       case (base, scalafixConfig, delegator) =>
@@ -356,9 +368,13 @@ case class Args(
             configuredSymtab |@|
             configuredRules(base, scalafixConfig) |@|
             resolvedPathReplace |@|
-            configuredDiffDisable
+            configuredDiffDisable |@|
+            configuredGlobal
         ).map {
-          case ((((root, symtab), rulez), pathReplace), diffDisable) =>
+          case (
+              ((((root, symtab), rulez), pathReplace), diffDisable),
+              global
+              ) =>
             ValidatedArgs(
               this,
               symtab,
@@ -369,7 +385,8 @@ case class Args(
               pathReplace,
               diffDisable,
               delegator,
-              semanticdbFilterMatcher
+              semanticdbFilterMatcher,
+              global
             )
         }
     }

scalafix-cli/src/main/scala/scalafix/internal/v1/MainOps.scala

@@ -35,6 +35,7 @@ import scalafix.internal.config.PrintStreamReporter
 import scalafix.internal.diff.DiffUtils
 import scalafix.v1.SyntacticDocument
 import scalafix.v1.SemanticDocument
+import scala.meta.interactive.InteractiveSemanticdb
 
 object MainOps {
 
@@ -185,6 +186,22 @@ object MainOps {
     }
   }
 
+  def compileWithGlobal(
+      args: ValidatedArgs,
+      doc: SyntacticDocument
+  ): Option[TextDocument] = {
+    args.global.map { g =>
+      InteractiveSemanticdb
+        .toTextDocument(g, doc.input.text)
+        .copy(
+          // TODO(olafur): avoid this MD5 compute
+          md5 = FingerprintOps.md5(
+            StandardCharsets.UTF_8.encode(CharBuffer.wrap(doc.input.chars))
+          )
+        )
+    }
+  }
+
   def unsafeHandleFile(args: ValidatedArgs, file: AbsolutePath): ExitStatus = {
     val input = args.input(file)
     val tree = LazyValue.later { () =>
@@ -198,7 +215,8 @@ object MainOps {
           doc,
           relpath,
           args.classLoader,
-          args.symtab
+          args.symtab,
+          () => compileWithGlobal(args, doc)
         )
         val (fix, messages) =
           args.rules.semanticPatch(sdoc, args.args.autoSuppressLinterErrors)

scalafix-cli/src/main/scala/scalafix/internal/v1/ValidatedArgs.scala

@@ -10,6 +10,7 @@ import scalafix.internal.config.ScalafixConfig
 import scalafix.internal.diff.DiffDisable
 import scala.meta.internal.symtab.SymbolTable
 import scalafix.internal.config.FilterMatcher
+import scala.tools.nsc.interactive.Global
 
 case class ValidatedArgs(
     args: Args,
@@ -21,7 +22,8 @@ case class ValidatedArgs(
     pathReplace: AbsolutePath => AbsolutePath,
     diffDisable: DiffDisable,
     callback: DelegatingMainCallback,
-    semanticdbFileFilter: FilterMatcher
+    semanticdbFileFilter: FilterMatcher,
+    global: Option[Global]
 ) {
 
   def input(file: AbsolutePath): Input = {

scalafix-core/src/main/scala/scalafix/internal/v1/Rules.scala

@@ -16,6 +16,8 @@ import scalafix.v1.SemanticDocument
 import scalafix.v1.SemanticRule
 import scalafix.v1.SyntacticDocument
 import scalafix.v1.SyntacticRule
+import scala.util.control.NonFatal
+import scala.collection.mutable
 
 case class Rules(rules: List[Rule] = Nil) {
 
@@ -32,6 +34,24 @@ case class Rules(rules: List[Rule] = Nil) {
   def syntacticRules: List[SyntacticRule] = rules.collect {
     case s: SyntacticRule => s
   }
+  def afterComplete(): List[(Rule, Throwable)] = {
+    foreachRule(_.afterComplete())
+  }
+  def beforeStart(): List[(Rule, Throwable)] = {
+    foreachRule(_.beforeStart())
+  }
+
+  private def foreachRule(fn: Rule => Unit): List[(Rule, Throwable)] = {
+    val buf = mutable.ListBuffer.empty[(Rule, Throwable)]
+    rules.foreach { rule =>
+      try fn(rule)
+      catch {
+        case NonFatal(e) =>
+          buf += (rule -> e)
+      }
+    }
+    buf.result()
+  }
 
   def addSuppression(
       tokens: Tokens,

scalafix-core/src/main/scala/scalafix/v1/Configuration.scala

@@ -1,9 +1,11 @@
 package scalafix.v1
 import metaconfig.Conf
+import scala.meta.io.AbsolutePath
 
 final class Configuration private (
     val scalaVersion: String,
     val scalacOptions: List[String],
+    val scalacClasspath: List[AbsolutePath],
     val conf: Conf
 ) {
 
@@ -15,21 +17,27 @@ final class Configuration private (
     copy(scalacOptions = options)
   }
 
+  def withScalacClasspath(classpath: List[AbsolutePath]): Configuration = {
+    copy(scalacClasspath = classpath)
+  }
+
   def withConf(conf: Conf): Configuration = {
     copy(conf = conf)
   }
 
   override def toString: String =
-    s"Configuration($scalaVersion, $scalacOptions, $conf)"
+    s"Configuration($scalaVersion, $scalacOptions, $scalacClasspath, $conf)"
 
   private[this] def copy(
       scalaVersion: String = this.scalaVersion,
       scalacOptions: List[String] = this.scalacOptions,
+      scalacClasspath: List[AbsolutePath] = this.scalacClasspath,
       conf: Conf = this.conf
   ): Configuration = {
     new Configuration(
       scalaVersion = scalaVersion,
       scalacOptions = scalacOptions,
+      scalacClasspath = scalacClasspath,
       conf = conf
     )
   }
@@ -40,6 +48,7 @@ object Configuration {
     new Configuration(
       scala.util.Properties.versionNumberString,
       Nil,
+      Nil,
       Conf.Obj()
     )
   }

scalafix-core/src/main/scala/scalafix/v1/SemanticDocument.scala

@@ -8,6 +8,8 @@ import scala.meta.io.RelativePath
 import scalafix.internal.v1._
 import scalafix.util.MatchingParens
 import scalafix.util.TokenList
+import scala.tools.nsc.interactive.Global
+import scala.meta.internal.semanticdb.TextDocument
 
 final class SemanticDocument private[scalafix] (
     private[scalafix] val internal: InternalSemanticDoc
@@ -52,7 +54,8 @@ object SemanticDocument {
       doc: SyntacticDocument,
       path: RelativePath,
       classLoader: ClassLoader,
-      symtab: SymbolTable
+      symtab: SymbolTable,
+      compile: () => Option[TextDocument]
   ): SemanticDocument = {
     val semanticdbRelPath = s"META-INF/semanticdb/$path.semanticdb"
     Option(classLoader.getResourceAsStream(semanticdbRelPath)) match {
@@ -67,7 +70,11 @@ object SemanticDocument {
         val impl = new InternalSemanticDoc(doc, sdoc, symtab)
         new SemanticDocument(impl)
       case None =>
-        throw Error.MissingSemanticdb(semanticdbRelPath)
+        compile() match {
+          case None => throw Error.MissingSemanticdb(semanticdbRelPath)
+          case Some(sdoc) =>
+            new SemanticDocument(new InternalSemanticDoc(doc, sdoc, symtab))
+        }
     }
   }
 }

scalafix-rules/src/main/scala/scala/meta/internal/proxy/GlobalProxy.scala

@@ -0,0 +1,10 @@
+package scala.meta.internal.proxy
+
+import scala.meta.internal.pc.MetalsGlobal
+import scala.reflect.internal.util.Position
+
+object GlobalProxy {
+  def typedTreeAt(g: MetalsGlobal, pos: Position): g.Tree = {
+    g.typedTreeAt(pos)
+  }
+}