Simplify LighterASTNode.toFirLightSourceElement

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/FirSourceChildren.kt

@@ -37,5 +37,5 @@ private fun FirPsiSourceElement<*>.getChild(types: Set<IElementType>, index: Int
 private fun FirLightSourceElement.getChild(types: Set<IElementType>, index: Int, depth: Int): FirSourceElement? {
     val visitor = LighterTreeElementFinderByType(treeStructure, types, index, depth)
 
-    return visitor.find(lighterASTNode)?.let { it.toFirLightSourceElement(it.startOffset, it.endOffset, treeStructure) }
+    return visitor.find(lighterASTNode)?.toFirLightSourceElement(treeStructure)
 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirModifierList.kt

@@ -76,11 +76,6 @@ val FirModifier<*>.lightNode: LighterASTNode? get() = (this as? FirLightModifier
 
 val FirModifier<*>.source: FirSourceElement?
     get() = when (this) {
-        is FirPsiModifier -> this.psi?.toFirPsiSourceElement()
-        is FirLightModifier -> {
-            // TODO pretty sure I got offsets wrong here
-            val startOffset = tree.getStartOffset(node)
-            val endOffset = tree.getEndOffset(node)
-            node.toFirLightSourceElement(startOffset, endOffset, tree)
-        }
+        is FirPsiModifier -> psi?.toFirPsiSourceElement()
+        is FirLightModifier -> node.toFirLightSourceElement(tree)
     }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirAnnotationArgumentChecker.kt

@@ -243,7 +243,7 @@ object FirAnnotationArgumentChecker : FirBasicDeclarationChecker() {
             is FirLightSourceElement -> {
                 val elementOfParent = source.treeStructure.getParent(source.lighterASTNode) ?: source.lighterASTNode
 
-                elementOfParent.toFirLightSourceElement(elementOfParent.startOffset, elementOfParent.endOffset, source.treeStructure)
+                elementOfParent.toFirLightSourceElement(source.treeStructure)
             }
             else ->
                 source

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExposedVisibilityDeclarationChecker.kt

@@ -236,7 +236,7 @@ object FirExposedVisibilityDeclarationChecker : FirMemberDeclarationChecker() {
             val kidsRef = Ref<Array<LighterASTNode?>>()
             this.treeStructure.getChildren(lighterASTNode, kidsRef)
             val identifier = kidsRef.get().find { it?.tokenType == KtTokens.IDENTIFIER }
-            identifier?.toFirLightSourceElement(this.treeStructure.getStartOffset(identifier), this.treeStructure.getEndOffset(identifier), this.treeStructure)
+            identifier?.toFirLightSourceElement(this.treeStructure)
         }
     }