Insert message "inline" into multiline code at point

3 files changed, 25 insertions, 29 deletions

diff --git a/src/dotty/tools/dotc/reporting/ConsoleReporter.scala b/src/dotty/tools/dotc/reporting/ConsoleReporter.scala
index 6ebd53bea..82edd6a83 100644
--- a/src/dotty/tools/dotc/reporting/ConsoleReporter.scala
+++ b/src/dotty/tools/dotc/reporting/ConsoleReporter.scala
@@ -32,9 +32,10 @@ class ConsoleReporter(
   def stripColor(str: String): String =
     str.replaceAll("\u001B\\[[;\\d]*m", "")
 
-  def sourceLines(pos: SourcePosition)(implicit ctx: Context): (List[String], Int) = {
+  def sourceLines(pos: SourcePosition)(implicit ctx: Context): (List[String], List[String], Int) = {
     var maxLen = Int.MinValue
-    val lines = pos.lines
+    def render(xs: List[Int]) =
+      xs.map(pos.source.offsetToLine(_))
       .map { lineNbr =>
         val prefix = s"${lineNbr + 1} |"
         maxLen = math.max(maxLen, prefix.length)
@@ -45,7 +46,8 @@ class ConsoleReporter(
         hl"$lnum$line"
       }
 
-    (lines, maxLen)
+    val (before, after) = pos.beforeAndAfterPoint
+    (render(before), render(after), maxLen)
   }
 
   def columnMarker(pos: SourcePosition, offset: Int)(implicit ctx: Context) = {
@@ -95,11 +97,11 @@ class ConsoleReporter(
   def printMessageAndPos(msg: Message, pos: SourcePosition, diagnosticLevel: String)(implicit ctx: Context): Unit = {
     printMessage(posStr(pos, diagnosticLevel, msg))
     if (pos.exists) {
-      val (srcLines, offset) = sourceLines(pos)
+      val (srcBefore, srcAfter, offset) = sourceLines(pos)
       val marker = columnMarker(pos, offset)
       val err = errorMsg(pos, msg.msg, offset)
 
-      printMessage((srcLines ::: marker :: err :: Nil).mkString("\n"))
+      printMessage((srcBefore ::: marker :: err :: srcAfter).mkString("\n"))
     } else printMessage(msg.msg)
   }
 
diff --git a/src/dotty/tools/dotc/reporting/diagnostic/Message.scala b/src/dotty/tools/dotc/reporting/diagnostic/Message.scala
index bdc899ea8..8b1f65673 100644
--- a/src/dotty/tools/dotc/reporting/diagnostic/Message.scala
+++ b/src/dotty/tools/dotc/reporting/diagnostic/Message.scala
@@ -15,6 +15,14 @@ object Message {
     new NoExplanation(str)
 }
 
+/** A `Message` contains all semantic information necessary to easily
+  * comprehend what caused the message to be logged. Each message can be turned
+  * into a `MessageContainer` which contains the log level and can later be
+  * consumed by a subclass of `Reporter`.
+  *
+  * @param errorId a unique number identifying the message, this will later be
+  *                used to reference documentation online
+  */
 abstract class Message(val errorId: Int) { self =>
   import messages._
 
diff --git a/src/dotty/tools/dotc/reporting/diagnostic/messages.scala b/src/dotty/tools/dotc/reporting/diagnostic/messages.scala
index e2b99af41..cc062ff92 100644
--- a/src/dotty/tools/dotc/reporting/diagnostic/messages.scala
+++ b/src/dotty/tools/dotc/reporting/diagnostic/messages.scala
@@ -90,8 +90,10 @@ object messages {
       }
 
       val code1 =
-        s"""|try $tryString catch {
-            |  case t: Throwable => ???
+        s"""|import scala.util.control.NonFatal
+            |
+            |try $tryString catch {
+            |  case NonFatal(e) => ???
             |}""".stripMargin
 
       val code2 =
@@ -108,7 +110,10 @@ object messages {
            |It is also possible to follow a ${"try"} immediately by a ${"finally"} - letting the
            |exception propagate - but still allowing for some clean up in ${"finally"}:
            |
-           |$code2""".stripMargin
+           |$code2
+           |
+           |It is recommended to use the ${"NonFatal"} extractor to catch all exceptions as it
+           |correctly handles transfer functions like ${"return"}.""".stripMargin
     }
   }
 
@@ -133,29 +138,10 @@ object messages {
     val kind = "Syntax"
     val msg =
       hl"""${"with"} as a type operator has been deprecated; use `&' instead"""
-    val explanation = {
-      val codeBlock1 =
-        """|trait A {
-           |  type T = Int
-           |}
-           |
-           |trait B {
-           |  type T = Double
-           |}""".stripMargin
-
+    val explanation =
       hl"""|Dotty introduces intersection types - `&' types. These replace the
            |use of the ${"with"} keyword. There are a few differences in
-           |semantics between intersection types and using `${"with"}'.
-           |
-           |`${"A with B"}' is ordered, `${"A & B"}' is not.
-           |
-           |In:
-           |
-           |$codeBlock1
-           |
-           |The type of `${"T"}' in `${"A with B"}' is ${"Int"} whereas in `${"A & B"}'
-           |the type of `${"T"}' is ${"Int & Double"}.""".stripMargin
-    }
+           |semantics between intersection types and using `${"with"}'.""".stripMargin
   }
 
   case class CaseClassMissingParamList(cdef: untpd.TypeDef)(implicit ctx: Context)