Minor: Extract code for checking Dalvik identifiers to frontend

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/checkers/dalvikIdentifierUtils.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+@file:JvmName("DalvikIdentifierUtils")
+package org.jetbrains.kotlin.resolve.jvm.checkers
+
+fun isValidDalvikIdentifier(identifier: String) = identifier.all { isValidDalvikCharacter(it) }
+
+// https://source.android.com/devices/tech/dalvik/dex-format.html#string-syntax
+private fun isValidDalvikCharacter(c: Char) = when (c) {
+    in 'A'..'Z' -> true
+    in 'a'..'z' -> true
+    in '0'..'9' -> true
+    '$', '-', '_' -> true
+    in '\u00a1' .. '\u1fff' -> true
+    in '\u2010' .. '\u2027' -> true
+    in '\u2030' .. '\ud7ff' -> true
+    in '\ue000' .. '\uffef' -> true
+    else -> false
+}

idea/idea-android/src/org/jetbrains/kotlin/android/inspection/IllegalIdentifierInspection.kt

@@ -39,6 +39,7 @@ import org.jetbrains.kotlin.idea.quickfix.RenameIdentifierFix
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtPsiUtil
 import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.resolve.jvm.checkers.isValidDalvikIdentifier
 import java.io.File
 
 class IllegalIdentifierInspection : AbstractKotlinInspection() {
@@ -59,7 +60,7 @@ class IllegalIdentifierInspection : AbstractKotlinInspection() {
                 // This is already an error
                 if (unquotedName.isEmpty()) return
 
-                if (!unquotedName.all { isValidDalvikCharacter(it) } && checkAndroidFacet(element)) {
+                if (!isValidDalvikIdentifier(unquotedName) && checkAndroidFacet(element)) {
                     if (element.isInUnitTests()) {
                         return
                     }
@@ -94,19 +95,6 @@ class IllegalIdentifierInspection : AbstractKotlinInspection() {
             private fun checkAndroidFacet(element: PsiElement): Boolean {
                 return element.getAndroidFacetForFile() != null || ApplicationManager.getApplication().isUnitTestMode
             }
-
-            // https://source.android.com/devices/tech/dalvik/dex-format.html#string-syntax
-            private fun isValidDalvikCharacter(c: Char) = when (c) {
-                in 'A'..'Z' -> true
-                in 'a'..'z' -> true
-                in '0'..'9' -> true
-                '$', '-', '_' -> true
-                in '\u00a1' .. '\u1fff' -> true
-                in '\u2010' .. '\u2027' -> true
-                in '\u2030' .. '\ud7ff' -> true
-                in '\ue000' .. '\uffef' -> true
-                else -> false
-            }
         }
     }