Custom message type for compiletime.error

compiler/src/dotty/tools/dotc/inlines/Inliner.scala

@@ -628,7 +628,7 @@ class Inliner(val call: tpd.Tree)(using Context):
         // The context in which we report should still use the existing context reporter
         val ctxOrigReporter = ctxToReport.fresh.setReporter(ctx.reporter)
         inContext(ctxOrigReporter) {
-          report.error(message, callToReport.srcPos)
+          report.error(new reporting.Custom(message), callToReport.srcPos)
         }
       case _ =>
     }

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

@@ -149,6 +149,15 @@ abstract class Message(val errorId: ErrorMessageID) { self =>
   override def toString = msg
 }
 
+/* a message generated by an inlined call to compiletime.error method */
+class Custom(_msg: String) extends Message(ErrorMessageID.NoExplanationID) {
+  def msg: String = _msg
+  def explain: String = ""
+  val kind: MessageKind = MessageKind.CustomCompiletime
+
+  override def toString(): String = msg
+}
+
 /** The fallback `Message` containing no explanation and having no `kind` */
 class NoExplanation(msgFn: => String) extends Message(ErrorMessageID.NoExplanationID) {
   def msg: String = msgFn

compiler/src/dotty/tools/dotc/reporting/MessageKind.scala

@@ -21,6 +21,7 @@ enum MessageKind:
   case MatchCaseUnreachable
   case Compatibility
   case PotentialIssue
+  case CustomCompiletime
 
   /** Human readable message that will end up being shown to the user.
    *  NOTE: This is only used in the situation where you have multiple words

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

@@ -187,7 +187,7 @@ trait MessageRendering {
             s"[E${"0" * (3 - errorNumber.toString.length) + errorNumber}] "
           else ""
         val kind =
-          if (message.kind == MessageKind.NoKind) then diagnosticString
+          if (message.kind == MessageKind.NoKind || message.kind == MessageKind.CustomCompiletime) then diagnosticString
           else s"${message.kind.message} $diagnosticString"
         val title =
           if fileAndPos.isEmpty then s"$errId$kind:" // this happens in dotty.tools.repl.ScriptedTests // TODO add name of source or remove `:` (and update test files)

compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -1127,7 +1127,7 @@ trait Implicits:
             case _ =>
               tryConversion
         }
-      if ctx.reporter.hasErrors
+      if (ctx.reporter.hasErrors && ctx.reporter.allErrors.exists(_.msg.kind != MessageKind.CustomCompiletime))
          || !cand.ref.symbol.isAccessibleFrom(cand.ref.prefix)
       then
         ctx.reporter.removeBufferedMessages