Factor out explanation header to Reporter

Author: felixmulder

src/dotty/tools/dotc/reporting/ConsoleReporter.scala

@@ -20,6 +20,8 @@ class ConsoleReporter(
     writer: PrintWriter = new PrintWriter(Console.err, true))
   extends Reporter with UniqueMessagePositions with HideNonSensicalMessages {
 
+  import Message._
+
   /** maximal number of error messages to be printed */
   protected def ErrorLimit = 100
 
@@ -42,17 +44,29 @@ class ConsoleReporter(
     }
   }
 
-  override def doReport(m: Message)(implicit ctx: Context): Unit = m match {
-    case m: Error =>
-      printMessageAndPos(m.message, m.pos, m.kind)
-      if (ctx.settings.prompt.value) displayPrompt()
-    case m: ConditionalWarning if !m.enablingOption.value =>
-    case m: MigrationWarning =>
-      printMessageAndPos(m.message, m.pos, m.kind)
-    case m: Warning =>
-      printMessageAndPos(m.message, m.pos, m.kind)
-    case _ =>
-      printMessageAndPos(m.message, m.pos, m.kind)
+  def printExplanation(m: Message): Unit =
+    printMessage(
+      s"""|
+          |Explanation
+          |===========
+          |${m.explanation}""".stripMargin
+    )
+
+  override def doReport(m: Message)(implicit ctx: Context): Unit = {
+    m match {
+      case m: Error =>
+        printMessageAndPos(m.message, m.pos, m.kind)
+        if (ctx.settings.prompt.value) displayPrompt()
+      case m: ConditionalWarning if !m.enablingOption.value =>
+      case m: MigrationWarning =>
+        printMessageAndPos(m.message, m.pos, m.kind)
+      case m: Warning =>
+        printMessageAndPos(m.message, m.pos, m.kind)
+      case _ =>
+        printMessageAndPos(m.message, m.pos, m.kind)
+    }
+
+    if (ctx.shouldExplain(m)) printExplanation(m)
   }
 
   def displayPrompt(): Unit = {

src/dotty/tools/dotc/reporting/FancyConsoleReporter.scala

@@ -9,6 +9,8 @@ import Reporter._
 import java.io.{ BufferedReader, IOException, PrintWriter }
 import scala.reflect.internal.util._
 import printing.SyntaxHighlighting._
+import printing.Highlighting._
+import diagnostic.Message
 
 /**
  * This class implements a more Fancy version (with colors!) of the regular
@@ -56,14 +58,13 @@ class FancyConsoleReporter(
   }
 
   def posStr(pos: SourcePosition, kind: String)(implicit ctx: Context) =
-    if (pos.exists) {
+    if (pos.exists) Blue({
       val file = pos.source.file.toString
 
-      val prefix = s"${Console.CYAN}-- $kind: $file "
+      val prefix = s"-- $kind: $file "
       prefix +
-      ("-" * math.max(ctx.settings.pageWidth.value - prefix.replaceAll("\u001B\\[[;\\d]*m", "").length, 0)) +
-      NoColor
-    } else ""
+      ("-" * math.max(ctx.settings.pageWidth.value - prefix.replaceAll("\u001B\\[[;\\d]*m", "").length, 0))
+    }).toString else ""
 
   /** Prints the message with the given position indication. */
   override def printMessageAndPos(msg: String, pos: SourcePosition, kind: String = "")(implicit ctx: Context): Unit = {
@@ -76,4 +77,24 @@ class FancyConsoleReporter(
       printMessage(List(src, marker, err).mkString("\n"))
     } else printMessage(msg)
   }
+
+  override def printExplanation(m: Message): Unit =
+    printMessage(
+      s"""|
+          |${Blue("Explanation")}
+          |${Blue("===========")}
+          |${m.explanation}""".stripMargin
+    )
+
+
+  override def summary: String = {
+    val b = new mutable.ListBuffer[String]
+    if (warningCount > 0)
+      b += countString(warningCount, Yellow("warning")) + " found"
+    if (errorCount > 0)
+      b += countString(errorCount, Red("error")) + " found"
+    for ((settingName, count) <- unreportedWarnings)
+      b += s"there were $count ${settingName.tail} ${Yellow("warning(s)")}; re-run with $settingName for details"
+    b.mkString("\n")
+  }
 }

src/dotty/tools/dotc/reporting/Reporter.scala

@@ -75,11 +75,8 @@ trait Reporting { this: Context =>
   def warning(msg: => String, pos: SourcePosition = NoSourcePosition): Unit =
     reporter.report(new Warning(msg, pos))
 
-  def explainWarning(msg: => MessageCreator, pos: SourcePosition = NoSourcePosition): Unit = {
+  def explainWarning(msg: => MessageCreator, pos: SourcePosition = NoSourcePosition): Unit =
     reporter.report(msg.warning(pos))
-    if (this.shouldExplain(msg))
-      reporter.report(new Info(msg.explanation, NoSourcePosition))
-  }
 
   def strictWarning(msg: => String, pos: SourcePosition = NoSourcePosition): Unit =
     if (this.settings.strict.value) error(msg, pos)
@@ -90,11 +87,8 @@ trait Reporting { this: Context =>
     reporter.report(new Error(msg, pos))
   }
 
-  def explainError(msg: => MessageCreator, pos: SourcePosition = NoSourcePosition): Unit = {
+  def explainError(msg: => MessageCreator, pos: SourcePosition = NoSourcePosition): Unit =
     reporter.report(msg.error(pos))
-    if (this.shouldExplain(msg))
-      reporter.report(new Info(msg.explanation, NoSourcePosition))
-  }
 
   def errorOrMigrationWarning(msg: => String, pos: SourcePosition = NoSourcePosition): Unit =
     if (ctx.scala2Mode) migrationWarning(msg, pos) else error(msg, pos)
@@ -267,7 +261,7 @@ abstract class Reporter extends interfaces.ReporterResult {
   }
 
   /** Returns a string meaning "n elements". */
-  private def countString(n: Int, elements: String): String = n match {
+  protected def countString(n: Int, elements: String): String = n match {
     case 0 => "no " + elements + "s"
     case 1 => "one " + elements
     case 2 => "two " + elements + "s"

src/dotty/tools/dotc/reporting/diagnostic/Message.scala

@@ -11,6 +11,16 @@ import java.util.Optional
 object Message {
   val nonSensicalStartTag = "<nonsensical>"
   val nonSensicalEndTag = "</nonsensical>"
+
+  implicit class MessageContext(val c: Context) extends AnyVal {
+    def shouldExplain(msg: Message): Boolean = {
+      implicit val ctx: Context = c
+      msg.explanation match {
+        case "" => false
+        case _ => ctx.settings.explain.value
+      }
+    }
+  }
 }
 
 class Message(

src/dotty/tools/dotc/reporting/diagnostic/MessageCreator.scala

@@ -7,16 +7,6 @@ import util.{SourcePosition, NoSourcePosition}
 import core.Contexts.Context
 
 object MessageCreator {
-  implicit class DiagnosticContext(val c: Context) extends AnyVal {
-    def shouldExplain(msg: MessageCreator): Boolean = {
-      implicit val ctx: Context = c
-      msg match {
-        case NoExplanation(_) => false
-        case _ => ctx.settings.explain.value
-      }
-    }
-  }
-
   implicit def toNoExplanation(str: String) =
     new NoExplanation(str)
 }

src/dotty/tools/dotc/reporting/diagnostic/syntax.scala

@@ -29,9 +29,7 @@ object syntax {
             |  // perform your cleanup here!
             |}""".stripMargin
 
-      hl"""|Explanation:
-           |============
-           |A ${"try"} expression should be followed by some mechanism to handle any exceptions
+      hl"""|A ${"try"} expression should be followed by some mechanism to handle any exceptions
            |thrown. Typically a ${"catch"} expression follows the ${"try"} and pattern matches
            |on any expected exceptions. For example:
            |

src/dotty/tools/dotc/reporting/diagnostic/tpe.scala

@@ -4,7 +4,7 @@ package reporting
 package diagnostic
 
 import dotc.core._
-import Contexts.Context, Decorators._, Symbols._
+import Contexts.Context, Decorators._, Symbols._, Names._
 import dotc.printing.SyntaxHighlighting._
 import util.{SourcePosition, NoSourcePosition}
 
@@ -35,13 +35,21 @@ object tpe {
 
       val caseDef = s"case $pat$guard => $body"
 
-      hl"""|Explanation
-           |===========
-           |For each ${"case"} bound variable names  have to be unique. In:
+      hl"""|For each ${"case"} bound variable names  have to be unique. In:
            |
            |$caseDef
            |
            |`${bind.name}` is not unique. Rename one of the bound variables!""".stripMargin
     }
   }
+
+  class MissingIdent(tree: untpd.Ident, treeKind: String, name: Name)(implicit ctx: Context) extends MessageCreator {
+    val kind = "Missing identifier"
+    val msg = em"not found: $treeKind$name"
+
+    val explanation = {
+      hl"""|An identifier for `${name.show}` is missing. This means that something
+           |has either been misspelt or you're forgetting an import""".stripMargin
+    }
+  }
 }