[IR] Move IrElement#sourceElement to the ir.tree module

This is so that it could be used from more places.
Namely, we need to use it from the `serialization.common` module.

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.KtPsiSourceFileLinesMapping
 import org.jetbrains.kotlin.KtSourceFileLinesMappingFromLineStartOffsets
 import org.jetbrains.kotlin.backend.common.CommonBackendErrors
-import org.jetbrains.kotlin.backend.common.sourceElement
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
@@ -56,10 +55,7 @@ import org.jetbrains.kotlin.ir.symbols.UnsafeDuringIrConstructionAPI
 import org.jetbrains.kotlin.ir.symbols.impl.IrConstructorPublicSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrSimpleFunctionPublicSymbolImpl
 import org.jetbrains.kotlin.ir.types.IrTypeSystemContext
-import org.jetbrains.kotlin.ir.util.KotlinMangler
+import org.jetbrains.kotlin.ir.util.*
-import org.jetbrains.kotlin.ir.util.NaiveSourceBasedFileEntryImpl
-import org.jetbrains.kotlin.ir.util.defaultType
-import org.jetbrains.kotlin.ir.util.fileOrNull
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtFile
 

compiler/ir/backend.common/src/org/jetbrains/kotlin/KtDiagnosticReporterWithImplicitIrBasedContext.kt

@@ -6,14 +6,13 @@
 package org.jetbrains.kotlin
 
 import org.jetbrains.kotlin.backend.common.psi.PsiSourceManager
-import org.jetbrains.kotlin.backend.common.sourceElement
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.diagnostics.AbstractKotlinSuppressCache
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.diagnostics.KtDiagnostic
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticReporterWithContext
-import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrDiagnosticReporter
+import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrAnnotationContainer
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrFile
@@ -22,6 +21,7 @@ import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.util.file
 import org.jetbrains.kotlin.ir.util.hasEqualFqName
+import org.jetbrains.kotlin.ir.util.sourceElement
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.FqName
 import java.util.*

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/Utils.kt

@@ -16,8 +16,6 @@
 
 package org.jetbrains.kotlin.backend.common
 
-import org.jetbrains.kotlin.AbstractKtSourceElement
-import org.jetbrains.kotlin.KtOffsetsOnlySourceElement
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrFile
 
@@ -30,7 +28,3 @@ fun <E> MutableList<E>.push(element: E) = this.add(element)
 fun <E> MutableList<E>.pop() = this.removeAt(size - 1)
 
 fun <E> MutableList<E>.peek(): E? = if (size == 0) null else this[size - 1]
-
-fun IrElement.sourceElement(): AbstractKtSourceElement? =
-    if (startOffset >= 0) KtOffsetsOnlySourceElement(this.startOffset, this.endOffset)
-    else null

compiler/ir/backend.jvm/codegen/src/org/jetbrains/kotlin/backend/jvm/codegen/JvmSignatureClashDetector.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.backend.jvm.codegen
 
 import org.jetbrains.kotlin.backend.common.lower.ANNOTATION_IMPLEMENTATION
-import org.jetbrains.kotlin.backend.common.sourceElement
 import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory1
@@ -14,6 +13,7 @@ import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.toIrBasedDescriptor
 import org.jetbrains.kotlin.ir.util.file
 import org.jetbrains.kotlin.ir.util.isFakeOverride
+import org.jetbrains.kotlin.ir.util.sourceElement
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.ConflictingJvmDeclarationsData
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmBackendErrors
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.MemberKind

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -5,6 +5,8 @@
 
 package org.jetbrains.kotlin.ir.util
 
+import org.jetbrains.kotlin.AbstractKtSourceElement
+import org.jetbrains.kotlin.KtOffsetsOnlySourceElement
 import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.builtins.UnsignedType
@@ -1611,3 +1613,7 @@ val IrDeclaration.isExpect
     get() = this is IrClass && isExpect ||
             this is IrFunction && isExpect ||
             this is IrProperty && isExpect
+
+fun IrElement.sourceElement(): AbstractKtSourceElement? =
+    if (startOffset >= 0) KtOffsetsOnlySourceElement(this.startOffset, this.endOffset)
+    else null