Uast: UastKotlinPsiVariable made isEquivalentTo it's physical PSI (KT-39174)

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/psi/UastKotlinPsiVariable.kt

@@ -67,6 +67,8 @@ class UastKotlinPsiVariable private constructor(
         return ktElement == (other as? UastKotlinPsiVariable)?.ktElement
     }
 
+    override fun isEquivalentTo(another: PsiElement?): Boolean = this == another || ktElement.isEquivalentTo(another)
+
     override fun hashCode() = ktElement.hashCode()
 
     companion object {

plugins/uast-kotlin/tests/KotlinUastResolveApiTest.kt

@@ -5,14 +5,13 @@
 
 package org.jetbrains.uast.test.kotlin
 
-import com.intellij.psi.PsiClassType
+import com.intellij.psi.*
-import com.intellij.psi.PsiMethod
-import com.intellij.psi.PsiType
 import com.intellij.testFramework.LightProjectDescriptor
 import junit.framework.TestCase
 import org.jetbrains.kotlin.idea.test.KotlinLightCodeInsightFixtureTestCase
 import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
 import org.jetbrains.kotlin.test.JUnit3WithIdeaConfigurationRunner
+import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.uast.*
 import org.jetbrains.uast.kotlin.KotlinUFunctionCallExpression
 import org.jetbrains.uast.test.env.kotlin.findElementByText
@@ -37,7 +36,16 @@ class KotlinUastResolveApiTest : KotlinLightCodeInsightFixtureTestCase() {
         )
 
         val refs = file.findUElementByTextFromPsi<UQualifiedReferenceExpression>("s.toUpperCase()")
-        TestCase.assertNotNull((refs.receiver.getExpressionType() as PsiClassType).resolve())
+        val receiver = refs.receiver
+        TestCase.assertEquals(CommonClassNames.JAVA_LANG_STRING, (receiver.getExpressionType() as PsiClassType).resolve()!!.qualifiedName!!)
+        val resolve = receiver.cast<UReferenceExpression>().resolve()
+
+        val variable = file.findUElementByTextFromPsi<UVariable>("val s = \"abc\"")
+        TestCase.assertEquals(resolve, variable.javaPsi)
+        TestCase.assertTrue(
+            "resolved expression $resolve should be equivalent to ${variable.sourcePsi}",
+            PsiManager.getInstance(project).areElementsEquivalent(resolve, variable.sourcePsi)
+        )
     }
 
     fun testMultiResolve() {