remove SuppressedMessage exception and update Diagnostic as needed

Author: samuelgruetter

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

@@ -10,23 +10,27 @@ import collection.mutable
 import config.Settings.Setting
 import config.Printers
 import java.lang.System.currentTimeMillis
+import typer.ErrorReporting.DiagnosticString
 
 object Reporter {
 
   class Diagnostic(msgFn: => String, val pos: SourcePosition, val severity: Severity) extends Exception {
+    import DiagnosticString._
     private var myMsg: String = null
-    private var myIsSuppressed: Boolean = false
+    private var myIsNonSensical: Boolean = false
     def msg: String = {
-      if (myMsg == null)
-        try myMsg = msgFn
-        catch {
-          case ex: SuppressedMessage =>
-            myIsSuppressed = true
-            myMsg = "<suppressed message>"
+      if (myMsg == null) {
+        myMsg = msgFn
+        if (myMsg.contains(nonSensicalStartTag)) {
+          myIsNonSensical = true
+          // myMsg might be composed of several d"..." invocations -> nested nonsensical tags possible
+          myMsg = myMsg.replaceAllLiterally(nonSensicalStartTag, "").replaceAllLiterally(nonSensicalEndTag, "")
         }
+      }
       myMsg
     }
-    def isSuppressed = { msg; myIsSuppressed }
+    def isNonSensical = { msg; myIsNonSensical }
+    def isSuppressed(implicit ctx: Context): Boolean = !ctx.settings.YshowSuppressedErrors.value && isNonSensical
     override def toString = s"$severity at $pos: $msg"
     override def getMessage() = msg
 
@@ -68,8 +72,6 @@ object Reporter {
     case UncheckedWARNING   => ctx.settings.unchecked
     case FeatureWARNING     => ctx.settings.feature
   }
-
-  class SuppressedMessage extends Exception
 }
 
 import Reporter._

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

@@ -10,7 +10,6 @@ import Applications._, Implicits._
 import util.Positions._
 import printing.Showable
 import printing.Disambiguation.disambiguated
-import reporting.Reporter.SuppressedMessage
 
 object ErrorReporting {