Kapt: Strict mode. Issue an error if the converter fails to process a class (#KT-25518, #KT-24272)

plugins/kapt3/kapt3-base/src/org/jetbrains/kotlin/kapt3/base/javac/KaptJavaLog.kt

@@ -224,10 +224,17 @@ class KaptJavaLog(
     }
 }
 
-fun KaptContext.kaptError(text: String): JCDiagnostic {
+private val LINE_SEPARATOR: String = System.getProperty("line.separator")
+
+fun KaptContext.kaptError(vararg line: String): JCDiagnostic {
+    val text = line.joinToString(LINE_SEPARATOR)
     return JCDiagnostic.Factory.instance(context).errorJava9Aware(null, null, "proc.messager", text)
 }
 
+fun KaptContext.reportKaptError(vararg line: String) {
+    compiler.log.report(kaptError(*line))
+}
+
 private fun JCDiagnostic.Factory.errorJava9Aware(
         source: DiagnosticSource?,
         pos: JCDiagnostic.DiagnosticPosition?,