Fix compiler warnings in compiler code

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/repl/replUtil.kt

@@ -34,12 +34,12 @@ fun String.replUnescapeLineBreaks() = StringUtil.replace(this, XML_REPLACEMENTS,
 fun String.replEscapeLineBreaks() = StringUtil.replace(this, SOURCE_CHARS, XML_REPLACEMENTS)
 
 fun String.replOutputAsXml(escapeType: ReplEscapeType): String {
-    val escapedXml = StringUtil.escapeXml(replEscapeLineBreaks())
+    val escapedXml = StringUtil.escapeXmlEntities(replEscapeLineBreaks())
     return "$XML_PREAMBLE<output type=\"$escapeType\">$escapedXml</output>"
 }
 
 fun String.replInputAsXml(): String {
-    val escapedXml = StringUtil.escapeXml(replEscapeLineBreaks())
+    val escapedXml = StringUtil.escapeXmlEntities(replEscapeLineBreaks())
     return "$XML_PREAMBLE<input>$escapedXml</input>"
 }
 
@@ -86,4 +86,4 @@ internal fun URLClassLoader.listLocalUrlsAsFiles(): List<File> {
 internal fun <T : Any> List<T>.ensureNotEmpty(error: String): List<T> {
     if (this.isEmpty()) throw IllegalStateException(error)
     return this
-}
+}

compiler/cli/src/org/jetbrains/kotlin/cli/common/Usage.java

@@ -102,6 +102,6 @@ public class Usage {
 
     private static void appendln(@NotNull StringBuilder sb, @NotNull String string) {
         sb.append(string);
-        StringsKt.appendln(sb);
+        sb.append('\n');
     }
 }

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/CliKotlinAsJavaSupport.kt

@@ -38,7 +38,7 @@ class CliKotlinAsJavaSupport(
     override fun getFacadeClassesInPackage(packageFqName: FqName, scope: GlobalSearchScope): Collection<PsiClass> {
         return findFacadeFilesInPackage(packageFqName, scope)
             .groupBy { it.javaFileFacadeFqName }
-            .mapNotNull { (facadeClassFqName, files) ->
+            .mapNotNull { (facadeClassFqName, _) ->
                 KtLightClassForFacade.createForFacade(psiManager, facadeClassFqName, scope)
             }
     }

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCoreEnvironment.kt

@@ -608,7 +608,10 @@ class KotlinCoreEnvironment private constructor(
         // made public for Upsource
         @JvmStatic
         @Deprecated("Use registerProjectServices(project) instead.", ReplaceWith("registerProjectServices(projectEnvironment.project)"))
-        fun registerProjectServices(projectEnvironment: JavaCoreProjectEnvironment, messageCollector: MessageCollector?) {
+        fun registerProjectServices(
+            projectEnvironment: JavaCoreProjectEnvironment,
+            @Suppress("UNUSED_PARAMETER") messageCollector: MessageCollector?
+        ) {
             registerProjectServices(projectEnvironment.project)
         }
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinToJVMBytecodeCompiler.kt

@@ -471,7 +471,6 @@ object KotlinToJVMBytecodeCompiler {
                     psiSource.psi, this.a, this.b, this.c, factory.psiDiagnosticFactory, severity
                 )
         }
-        throw IllegalArgumentException("Unknown diagnostics: $this")
     }
 
     private fun getBuildFilePaths(buildFile: File?, sourceFilePaths: List<String>): List<String> =