Fix realization of LightClass methods by KtLightClassForSourceDeclaration

#KT-31022 Fixed

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KtLightClassForSourceDeclaration.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.asJava.classes
@@ -22,6 +11,7 @@ import com.intellij.openapi.diagnostic.Logger
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.Comparing
 import com.intellij.openapi.util.Key
+import com.intellij.openapi.util.TextRange
 import com.intellij.openapi.util.registry.Registry
 import com.intellij.psi.*
 import com.intellij.psi.impl.PsiSubstitutorImpl
@@ -48,10 +38,7 @@ import org.jetbrains.kotlin.asJava.builder.InvalidLightClassDataHolder
 import org.jetbrains.kotlin.asJava.builder.LightClassData
 import org.jetbrains.kotlin.asJava.builder.LightClassDataHolder
 import org.jetbrains.kotlin.asJava.builder.LightClassDataProviderForClassOrObject
-import org.jetbrains.kotlin.asJava.elements.FakeFileForLightClass
-import org.jetbrains.kotlin.asJava.elements.KtLightIdentifier
-import org.jetbrains.kotlin.asJava.elements.KtLightModifierList
-import org.jetbrains.kotlin.asJava.elements.KtLightPsiReferenceList
+import org.jetbrains.kotlin.asJava.elements.*
 import org.jetbrains.kotlin.asJava.hasInterfaceDefaultImpls
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.builtins.jvm.JavaToKotlinClassMap
@@ -77,6 +64,16 @@ abstract class KtLightClassForSourceDeclaration(
     StubBasedPsiElement<KotlinClassOrObjectStub<out KtClassOrObject>> {
     private val lightIdentifier = KtLightIdentifier(this, classOrObject)
 
+    override fun getText() = kotlinOrigin.text ?: ""
+
+    override fun getTextRange(): TextRange = kotlinOrigin.textRange ?: TextRange.EMPTY_RANGE
+
+    override fun getTextOffset() = kotlinOrigin.textOffset
+
+    override fun getStartOffsetInParent() = kotlinOrigin.startOffsetInParent
+
+    override fun isWritable() = kotlinOrigin.isWritable
+
     private val _extendsList by lazyPub { createExtendsList() }
     private val _implementsList by lazyPub { createImplementsList() }
 

idea/tests/org/jetbrains/kotlin/asJava/LightClassFromTextTest.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.asJava
 
+import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiClassType
 import com.intellij.psi.PsiType
@@ -32,6 +33,21 @@ class LightClassFromTextTest : KotlinLightCodeInsightFixtureTestCase() {
         assertEquals("O", classes[1].qualifiedName)
     }
 
+    fun testLightClassImplementation() {
+        myFixture.configureByText("Dummy.kt", "") as KtFile
+        val classes = classesFromText("import something\nclass C;")
+
+        assertEquals(1, classes.size)
+
+        val classC = classes[0]
+        assertEquals("C", classC.qualifiedName)
+        assertEquals("class C", classC.text)
+        assertEquals(TextRange(17, 24), classC.textRange)
+        assertEquals(23, classC.textOffset)
+        assertEquals(17, classC.startOffsetInParent)
+        assertTrue(classC.isWritable)
+    }
+
     fun testFileClass() {
         myFixture.configureByText("A.kt", "fun f() {}") as KtFile
         val classes = classesFromText("fun g() {}", fileName = "A.kt")