FIR checker: revisit per-label iterations to avoid !!

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/CfaUtils.kt

@@ -128,15 +128,14 @@ class PropertyInitializationInfoCollector(private val localProperties: Set<FirPr
 }
 
 internal fun <P : PathAwareControlFlowInfo<P, S>, S : ControlFlowInfo<S, K, EventOccurrencesRange>, K : Any> addRange(
-    info: P,
+    pathAwareInfo: P,
     key: K,
     range: EventOccurrencesRange,
     constructor: (PersistentMap<EdgeLabel, S>) -> P
 ): P {
     var resultMap = persistentMapOf<EdgeLabel, S>()
     // before: { |-> { p1 |-> PI1 }, l1 |-> { p2 |-> PI2 } }
-    for (label in info.keys) {
-        val dataPerLabel = info[label]!!
+    for ((label, dataPerLabel) in pathAwareInfo) {
         val existingKind = dataPerLabel[key] ?: EventOccurrencesRange.ZERO
         val kind = existingKind + range
         resultMap = resultMap.put(label, dataPerLabel.put(key, kind))

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/FirCallsEffectAnalyzer.kt

@@ -89,9 +89,9 @@ object FirCallsEffectAnalyzer : FirControlFlowChecker() {
         for ((symbol, effectDeclaration) in functionalTypeEffects) {
             graph.exitNode.previousCfgNodes.forEach { node ->
                 val requiredRange = effectDeclaration.kind
-                val info = invocationData.getValue(node)
-                for (label in info.keys) {
-                    if (investigate(info.getValue(label), symbol, requiredRange, function, reporter)) {
+                val pathAwareInfo = invocationData.getValue(node)
+                for (info in pathAwareInfo.values) {
+                    if (investigate(info, symbol, requiredRange, function, reporter)) {
                         // To avoid duplicate reports, stop investigating remaining paths once reported.
                         break
                     }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/FirPropertyInitializationAnalyzer.kt

@@ -49,8 +49,8 @@ object FirPropertyInitializationAnalyzer : AbstractFirPropertyInitializationChec
             if (symbol !in localProperties) return
             if (symbol.fir.isLateInit) return
             val pathAwareInfo = data.getValue(node)
-            for (label in pathAwareInfo.keys) {
-                if (investigate(pathAwareInfo[label]!!, symbol, node)) {
+            for (info in pathAwareInfo.values) {
+                if (investigate(info, symbol, node)) {
                     // To avoid duplicate reports, stop investigating remaining paths if the property is not initialized at any path.
                     break
                 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/extended/UnusedChecker.kt

@@ -44,8 +44,8 @@ object UnusedChecker : FirControlFlowChecker() {
         override fun visitVariableAssignmentNode(node: VariableAssignmentNode) {
             val variableSymbol = (node.fir.calleeReference as? FirResolvedNamedReference)?.resolvedSymbol ?: return
             val dataPerNode = data[node] ?: return
-            for (label in dataPerNode.keys) {
-                val data = dataPerNode[label]!![variableSymbol] ?: continue
+            for (dataPerLabel in dataPerNode.values) {
+                val data = dataPerLabel[variableSymbol] ?: continue
                 if (data == VariableStatus.ONLY_WRITTEN_NEVER_READ) {
                     // todo: report case like "a += 1" where `a` `doesn't writes` different way (special for Idea)
                     val source = node.fir.lValue.source
@@ -60,8 +60,8 @@ object UnusedChecker : FirControlFlowChecker() {
             val variableSymbol = node.fir.symbol
             if (variableSymbol.isLoopIterator) return
             val dataPerNode = data[node] ?: return
-            for (label in dataPerNode.keys) {
-                val data = dataPerNode[label]!![variableSymbol] ?: continue
+            for (dataPerLabel in dataPerNode.values) {
+                val data = dataPerLabel[variableSymbol] ?: continue
 
                 val variableSource = variableSymbol.fir.source.takeIf { it?.elementType != KtNodeTypes.DESTRUCTURING_DECLARATION }
                 when {
@@ -242,14 +242,13 @@ object UnusedChecker : FirControlFlowChecker() {
         }
 
         private fun update(
-            info: PathAwareVariableStatusInfo,
+            pathAwareInfo: PathAwareVariableStatusInfo,
             symbol: FirPropertySymbol,
             updater: (VariableStatus?) -> VariableStatus?,
         ): PathAwareVariableStatusInfo {
             var resultMap = persistentMapOf<EdgeLabel, VariableStatusInfo>()
             var changed = false
-            for (label in info.keys) {
-                val dataPerLabel = info[label]!!
+            for ((label, dataPerLabel) in pathAwareInfo) {
                 val v = updater.invoke(dataPerLabel[symbol])
                 if (v != null) {
                     resultMap = resultMap.put(label, dataPerLabel.put(symbol, v))
@@ -258,7 +257,7 @@ object UnusedChecker : FirControlFlowChecker() {
                     resultMap = resultMap.put(label, dataPerLabel)
                 }
             }
-            return if (changed) PathAwareVariableStatusInfo(resultMap) else info
+            return if (changed) PathAwareVariableStatusInfo(resultMap) else pathAwareInfo
         }
     }