Merge pull request #1606 from felixmulder/topic/fix-inline-context

Fix #1604: print outer context if applicable

Author: felixmulder

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

@@ -2,11 +2,10 @@ package dotty.tools
 package dotc
 package reporting
 
-import util.SourcePosition
 import core.Contexts._
 import java.io.{ BufferedReader, PrintWriter }
 import diagnostic.{ Message, MessageContainer }
-import diagnostic.messages._
+import diagnostic.messages.{ Error, Warning, ConditionalWarning }
 
 /**
   * This class implements a Reporter that displays messages on a text console
@@ -25,48 +24,40 @@ class ConsoleReporter(
   def printMessage(msg: String): Unit = { writer.print(msg + "\n"); writer.flush() }
 
   /** Prints the message with the given position indication. */
-  def printMessageAndPos(msg: Message, pos: SourcePosition, diagnosticLevel: String)(implicit ctx: Context): Boolean = {
-    printMessage(messageAndPos(msg, pos, diagnosticLevel))
-    true
-  }
-
-  def printExplanation(m: Message)(implicit ctx: Context): Unit = {
-    printMessage(explanation(m))
-  }
-
-  override def doReport(m: MessageContainer)(implicit ctx: Context): Unit = {
+  def doReport(m: MessageContainer)(implicit ctx: Context): Unit = {
     val didPrint = m match {
       case m: Error =>
-        val didPrint = printMessageAndPos(m.contained, m.pos, diagnosticLevel(m))
+        printMessage(messageAndPos(m.contained, m.pos, diagnosticLevel(m)))
         if (ctx.settings.prompt.value) displayPrompt()
-        didPrint
+        true
       case m: ConditionalWarning if !m.enablingOption.value =>
         false
       case m =>
-        printMessageAndPos(m.contained, m.pos, diagnosticLevel(m))
+        printMessage(messageAndPos(m.contained, m.pos, diagnosticLevel(m)))
+        true
     }
 
     if (didPrint && ctx.shouldExplain(m))
-      printExplanation(m.contained)
+      printMessage(explanation(m.contained))
     else if (didPrint && m.contained.explanation.nonEmpty)
       printMessage("\nlonger explanation available when compiling with `-explain`")
   }
 
-  def displayPrompt(): Unit = {
-    writer.print("\na)bort, s)tack, r)esume: ")
-    writer.flush()
+  /** Show prompt if `-Xprompt` is passed as a flag to the compiler */
+  def displayPrompt()(implicit ctx: Context): Unit = {
+    printMessage("\na)bort, s)tack, r)esume: ")
+    flush()
     if (reader != null) {
       val response = reader.read().asInstanceOf[Char].toLower
       if (response == 'a' || response == 's') {
         Thread.dumpStack()
         if (response == 'a')
           sys.exit(1)
       }
-      writer.print("\n")
-      writer.flush()
+      print("\n")
+      flush()
     }
   }
 
   override def flush()(implicit ctx: Context): Unit = { writer.flush() }
 }
-

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

@@ -12,9 +12,30 @@ import util.SourcePosition
 import scala.collection.mutable
 
 trait MessageRendering {
+  /** Remove ANSI coloring from `str`, useful for getting real length of
+    * strings
+    *
+    * @return string stripped of ANSI escape codes
+    */
   def stripColor(str: String): String =
     str.replaceAll("\u001B\\[[;\\d]*m", "")
 
+  /** When inlining a method call, if there's an error we'd like to get the
+    * outer context and the `pos` at which the call was inlined.
+    *
+    * @return a list of strings with inline locations
+    */
+  def outer(pos: SourcePosition, prefix: String)(implicit ctx: Context): List[String] =
+    if (pos.outer.exists) {
+       s"$prefix| This location is in code that was inlined at ${pos.outer}" ::
+       outer(pos.outer, prefix)
+    } else Nil
+
+  /** Get the sourcelines before and after the position, as well as the offset
+    * for rendering line numbers
+    *
+    * @return (lines before error, lines after error, line numbers offset)
+    */
   def sourceLines(pos: SourcePosition)(implicit ctx: Context): (List[String], List[String], Int) = {
     var maxLen = Int.MinValue
     def render(xs: List[Int]) =
@@ -33,6 +54,7 @@ trait MessageRendering {
     (render(before), render(after), maxLen)
   }
 
+  /** The column markers aligned under the error */
   def columnMarker(pos: SourcePosition, offset: Int)(implicit ctx: Context): String = {
     val prefix = " " * (offset - 1)
     val whitespace = " " * pos.startColumn
@@ -45,21 +67,30 @@ trait MessageRendering {
     s"$prefix|$whitespace${carets.show}"
   }
 
+  /** The error message (`msg`) aligned under `pos`
+    *
+    * @return aligned error message
+    */
   def errorMsg(pos: SourcePosition, msg: String, offset: Int)(implicit ctx: Context): String = {
     val leastWhitespace = msg.lines.foldLeft(Int.MaxValue) { (minPad, line) =>
       val lineLength = stripColor(line).length
-      val padding =
-        math.min(math.max(0, ctx.settings.pageWidth.value - offset - lineLength), offset + pos.startColumn)
+      val currPad = math.min(
+        math.max(0, ctx.settings.pageWidth.value - offset - lineLength),
+        offset + pos.startColumn
+      )
 
-      if (padding < minPad) padding
-      else minPad
+      math.min(currPad, minPad)
     }
 
     msg.lines
-      .map { line => " " * (offset - 1) + "|" + (" " * (leastWhitespace - offset)) + line }
+      .map { line => " " * (offset - 1) + "|" + (" " * (leastWhitespace - offset)) + line}
       .mkString(sys.props("line.separator"))
   }
 
+  /** The separator between errors containing the source file and error type
+    *
+    * @return separator containing error location and kind
+    */
   def posStr(pos: SourcePosition, diagnosticLevel: String, message: Message)(implicit ctx: Context): String =
     if (pos.exists) Blue({
       val file = pos.source.file.toString
@@ -76,28 +107,32 @@ trait MessageRendering {
         ("-" * math.max(ctx.settings.pageWidth.value - stripColor(prefix).length, 0))
     }).show else ""
 
+  /** Explanation rendered under "Explanation" header */
   def explanation(m: Message)(implicit ctx: Context): String = {
-    val sb = new StringBuilder(hl"""|
-                                    |${Blue("Explanation")}
-                                    |${Blue("===========")}""".stripMargin)
+    val sb = new StringBuilder(
+      hl"""|
+           |${Blue("Explanation")}
+           |${Blue("===========")}"""
+    )
     sb.append('\n').append(m.explanation)
     if (m.explanation.lastOption != Some('\n')) sb.append('\n')
     sb.toString
   }
 
+  /** The whole message rendered from `msg` */
   def messageAndPos(msg: Message, pos: SourcePosition, diagnosticLevel: String)(implicit ctx: Context): String = {
     val sb = mutable.StringBuilder.newBuilder
     sb.append(posStr(pos, diagnosticLevel, msg)).append('\n')
     if (pos.exists) {
       val (srcBefore, srcAfter, offset) = sourceLines(pos)
       val marker = columnMarker(pos, offset)
       val err = errorMsg(pos, msg.msg, offset)
-      sb.append((srcBefore ::: marker :: err :: srcAfter).mkString("\n"))
+      sb.append((srcBefore ::: marker :: err :: outer(pos, " " * (offset - 1)) ::: srcAfter).mkString("\n"))
     } else sb.append(msg.msg)
     sb.toString
   }
 
-  def diagnosticLevel(cont: MessageContainer): String = {
+  def diagnosticLevel(cont: MessageContainer): String =
     cont match {
       case m: Error => "Error"
       case m: FeatureWarning => "Feature Warning"
@@ -107,5 +142,4 @@ trait MessageRendering {
       case m: Warning => "Warning"
       case m: Info => "Info"
     }
-  }
 }

src/dotty/tools/dotc/typer/Inliner.scala

@@ -236,10 +236,12 @@ object Inliner {
   def inlineCall(tree: Tree, pt: Type)(implicit ctx: Context): Tree =
     if (enclosingInlineds.length < ctx.settings.xmaxInlines.value)
       new Inliner(tree, bodyToInline(tree.symbol)).inlined(pt)
-    else errorTree(tree,
-      i"""Maximal number of successive inlines (${ctx.settings.xmaxInlines.value}) exceeded,
-                   | Maybe this is caused by a recursive inline method?
-                   | You can use -Xmax:inlines to change the limit.""")
+    else errorTree(
+      tree,
+      i"""|Maximal number of successive inlines (${ctx.settings.xmaxInlines.value}) exceeded,
+          |Maybe this is caused by a recursive inline method?
+          |You can use -Xmax:inlines to change the limit."""
+    )
 
   /** Replace `Inlined` node by a block that contains its bindings and expansion */
   def dropInlined(inlined: tpd.Inlined)(implicit ctx: Context): Tree = {