FIR: Support safe-calls in renderers

^KT-38444 In Progress

compiler/fir/dump/src/org/jetbrains/kotlin/fir/dump/HtmlFirDump.kt

@@ -1312,8 +1312,11 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
         }
     }
 
-    private fun FlowContent.generate(functionCall: FirFunctionCall) {
-        generateReceiver(functionCall)
+    private fun FlowContent.generate(functionCall: FirFunctionCall, skipReceiver: Boolean = false) {
+
+        if (!skipReceiver) {
+            generateReceiver(functionCall)
+        }
 
         generate(functionCall.calleeReference)
         generateTypeProjections(functionCall.typeArguments)
@@ -1567,6 +1570,10 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
                 is FirVarargArgumentsExpression -> generate(expression)
                 is FirResolvedReifiedParameterReference -> generate(expression)
                 is FirComparisonExpression -> generate(expression)
+                is FirSafeCallExpression -> generate(expression)
+                is FirCheckedSafeCallSubject -> {
+                    +"\$subj\$"
+                }
                 else -> inlineUnsupported(expression)
             }
         }
@@ -1578,6 +1585,30 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
         generate(comparisonExpression.right)
     }
 
+    private fun FlowContent.generate(safeCallExpression: FirSafeCallExpression) {
+        generate(safeCallExpression.receiver)
+
+        +"?."
+
+        val nestedQualifier = safeCallExpression.regularQualifiedAccess
+        if (nestedQualifier.explicitReceiver == safeCallExpression.checkedSubject.value) {
+            when (nestedQualifier) {
+                is FirFunctionCall -> {
+                    return generate(nestedQualifier, skipReceiver = true)
+                }
+                is FirQualifiedAccessExpression -> {
+                    return generate(nestedQualifier, skipReceiver = true)
+                }
+            }
+        }
+
+        +"{ "
+
+        generate(nestedQualifier)
+
+        +" }"
+    }
+
     private fun FlowContent.generate(resolvedReifiedParameterReference: FirResolvedReifiedParameterReference) {
         val typeParameter = resolvedReifiedParameterReference.symbol.fir
         +typeParameter.name.identifier
@@ -1593,8 +1624,10 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
         generate(binaryLogicExpression.rightOperand)
     }
 
-    private fun FlowContent.generate(qualifiedAccessExpression: FirQualifiedAccessExpression) {
-        generateReceiver(qualifiedAccessExpression)
+    private fun FlowContent.generate(qualifiedAccessExpression: FirQualifiedAccessExpression, skipReceiver: Boolean = false) {
+        if (!skipReceiver) {
+            generateReceiver(qualifiedAccessExpression)
+        }
         generate(qualifiedAccessExpression.calleeReference)
     }
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirRenderer.kt

@@ -510,6 +510,17 @@ class FirRenderer(builder: StringBuilder, private val mode: RenderMode = RenderM
         }
     }
 
+    override fun visitSafeCallExpression(safeCallExpression: FirSafeCallExpression) {
+        safeCallExpression.receiver.accept(this)
+        print("?.{ ")
+        safeCallExpression.regularQualifiedAccess.accept(this)
+        print(" }")
+    }
+
+    override fun visitCheckedSafeCallSubject(checkedSafeCallSubject: FirCheckedSafeCallSubject) {
+        print("\$subj\$")
+    }
+
     override fun visitTypedDeclaration(typedDeclaration: FirTypedDeclaration) {
         visitDeclaration(typedDeclaration)
     }

compiler/visualizer/render-fir/src/org/jetbrains/kotlin/compiler/visualizer/FirVisualizer.kt

@@ -406,6 +406,17 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
             //skip rendering for as/as?/is/!is
         }
 
+        override fun visitSafeCallExpression(safeCallExpression: FirSafeCallExpression, data: StringBuilder) {
+            safeCallExpression.receiver.accept(this, data)
+            data.append("?.{ ")
+            safeCallExpression.regularQualifiedAccess.accept(this, data)
+            data.append(" }")
+        }
+
+        override fun visitCheckedSafeCallSubject(checkedSafeCallSubject: FirCheckedSafeCallSubject, data: StringBuilder) {
+            data.append("\$subj\$")
+        }
+
         override fun visitFunctionCall(functionCall: FirFunctionCall, data: StringBuilder) {
             when (val callee = functionCall.calleeReference) {
                 is FirResolvedNamedReference -> {