FIR DFA: split flow for postponed lambdas from a single node

This removes the need for hacks around the order in which function
call arguments are visited, fixes called-in-place lambda arguments
for augmented assignment operators, and makes CFG dumps a bit prettier.

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/CFGNode.kt

@@ -243,9 +243,10 @@ class ExitDefaultArgumentsNode(owner: ControlFlowGraph, override val fir: FirVal
 
 // ----------------------------------- Anonymous function -----------------------------------
 
-class PostponedLambdaEnterNode(owner: ControlFlowGraph, override val fir: FirAnonymousFunctionExpression, level: Int, id: Int) : CFGNodeWithSubgraphs<FirAnonymousFunctionExpression>(owner, level, id) {
+class SplitPostponedLambdasNode(owner: ControlFlowGraph, override val fir: FirStatement, val lambdas: List<FirAnonymousFunction>, level: Int, id: Int)
+    : CFGNodeWithSubgraphs<FirStatement>(owner, level, id) {
     override fun <R, D> accept(visitor: ControlFlowGraphVisitor<R, D>, data: D): R {
-        return visitor.visitPostponedLambdaEnterNode(this, data)
+        return visitor.visitSplitPostponedLambdasNode(this, data)
     }
 }
 
@@ -261,9 +262,9 @@ class MergePostponedLambdaExitsNode(owner: ControlFlowGraph, override val fir: F
     }
 }
 
-class AnonymousFunctionExpressionExitNode(owner: ControlFlowGraph, override val fir: FirAnonymousFunctionExpression, level: Int, id: Int) : CFGNode<FirAnonymousFunctionExpression>(owner, level, id) {
+class AnonymousFunctionExpressionNode(owner: ControlFlowGraph, override val fir: FirAnonymousFunctionExpression, level: Int, id: Int) : CFGNodeWithSubgraphs<FirAnonymousFunctionExpression>(owner, level, id) {
     override fun <R, D> accept(visitor: ControlFlowGraphVisitor<R, D>, data: D): R {
-        return visitor.visitAnonymousFunctionExpressionExitNode(this, data)
+        return visitor.visitAnonymousFunctionExpressionNode(this, data)
     }
 }
 

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/CFGNodeRenderer.kt

@@ -98,12 +98,10 @@ fun CFGNode<*>.render(): String =
 
                 is WhenSubjectExpressionExitNode -> "Exit ${'$'}subj"
 
-                is PostponedLambdaEnterNode -> "Postponed enter to lambda"
+                is SplitPostponedLambdasNode -> "Postponed enter to lambda"
                 is PostponedLambdaExitNode -> "Postponed exit from lambda"
-
-                is AnonymousFunctionExpressionExitNode -> "Exit anonymous function expression"
-
                 is MergePostponedLambdaExitsNode -> "Merge postponed lambda exits"
+                is AnonymousFunctionExpressionNode -> "Exit anonymous function expression"
 
                 is ClassEnterNode -> "Enter class ${owner.name}"
                 is ClassExitNode -> "Exit class ${owner.name}"

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphVisitor.kt

@@ -36,7 +36,7 @@ abstract class ControlFlowGraphVisitor<out R, in D> {
 
     // ----------------------------------- Anonymous function -----------------------------------
 
-    open fun visitPostponedLambdaEnterNode(node: PostponedLambdaEnterNode, data: D): R {
+    open fun visitSplitPostponedLambdasNode(node: SplitPostponedLambdasNode, data: D): R {
         return visitNode(node, data)
     }
 
@@ -48,7 +48,7 @@ abstract class ControlFlowGraphVisitor<out R, in D> {
         return visitNode(node, data)
     }
 
-    open fun visitAnonymousFunctionExpressionExitNode(node: AnonymousFunctionExpressionExitNode, data: D): R {
+    open fun visitAnonymousFunctionExpressionNode(node: AnonymousFunctionExpressionNode, data: D): R {
         return visitNode(node, data)
     }
 

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphVisitorVoid.kt

@@ -20,9 +20,13 @@ abstract class ControlFlowGraphVisitorVoid : ControlFlowGraphVisitor<Unit, Nothi
         visitNode(node)
     }
 
+    open fun visitLocalFunctionDeclarationNode(node: LocalFunctionDeclarationNode) {
+        visitNode(node)
+    }
+
     // ----------------------------------- Anonymous function -----------------------------------
 
-    open fun visitPostponedLambdaEnterNode(node: PostponedLambdaEnterNode) {
+    open fun visitSplitPostponedLambdasNode(node: SplitPostponedLambdasNode) {
         visitNode(node)
     }
 
@@ -34,6 +38,10 @@ abstract class ControlFlowGraphVisitorVoid : ControlFlowGraphVisitor<Unit, Nothi
         visitNode(node)
     }
 
+    open fun visitAnonymousFunctionExpressionNode(node: AnonymousFunctionExpressionNode) {
+        visitNode(node)
+    }
+
     // ----------------------------------- Anonymous object -----------------------------------
 
     open fun visitAnonymousObjectExitNode(node: AnonymousObjectExitNode) {
@@ -313,10 +321,14 @@ abstract class ControlFlowGraphVisitorVoid : ControlFlowGraphVisitor<Unit, Nothi
         visitFunctionExitNode(node)
     }
 
+    final override fun visitLocalFunctionDeclarationNode(node: LocalFunctionDeclarationNode, data: Nothing?) {
+        visitLocalFunctionDeclarationNode(node)
+    }
+
     // ----------------------------------- Anonymous function -----------------------------------
 
-    final override fun visitPostponedLambdaEnterNode(node: PostponedLambdaEnterNode, data: Nothing?) {
-        visitPostponedLambdaEnterNode(node)
+    final override fun visitSplitPostponedLambdasNode(node: SplitPostponedLambdasNode, data: Nothing?) {
+        visitSplitPostponedLambdasNode(node)
     }
 
     final override fun visitPostponedLambdaExitNode(node: PostponedLambdaExitNode, data: Nothing?) {
@@ -327,6 +339,10 @@ abstract class ControlFlowGraphVisitorVoid : ControlFlowGraphVisitor<Unit, Nothi
         visitMergePostponedLambdaExitsNode(node)
     }
 
+    final override fun visitAnonymousFunctionExpressionNode(node: AnonymousFunctionExpressionNode, data: Nothing?) {
+        visitAnonymousFunctionExpressionNode(node)
+    }
+
     // ----------------------------------- Anonymous object -----------------------------------
 
     final override fun visitAnonymousObjectExitNode(node: AnonymousObjectExitNode, data: Nothing?) {