Move PsiSourceElement to psi

compiler/psi/src/org/jetbrains/kotlin/resolve/source/PsiSourceElement.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2010-2021 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.resolve.source
+
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiFile
+import org.jetbrains.kotlin.descriptors.SourceElement
+import org.jetbrains.kotlin.descriptors.SourceFile
+
+interface PsiSourceElement : SourceElement {
+    val psi: PsiElement?
+
+    override fun getContainingFile(): SourceFile = psi?.containingFile?.let(::PsiSourceFile) ?: SourceFile.NO_SOURCE_FILE
+}
+
+class PsiSourceFile(val psiFile: PsiFile) : SourceFile {
+    override fun equals(other: Any?): Boolean = other is PsiSourceFile && psiFile == other.psiFile
+
+    override fun hashCode(): Int = psiFile.hashCode()
+
+    override fun toString(): String = psiFile.virtualFile.path
+
+    override fun getName(): String? = psiFile.virtualFile?.name
+}
+
+fun SourceElement.getPsi(): PsiElement? = (this as? PsiSourceElement)?.psi