isLocalVariable used together with isStableIdentifier for smart casts (both false positives now fail, but all three KT-3175 pass instead)

Author: mglukhikh

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/CandidateResolver.java

@@ -446,7 +446,7 @@ private static JetType updateResultTypeForSmartCasts(
         if (deparenthesizedArgument == null || type == null) return type;
 
         DataFlowValue dataFlowValue = DataFlowValueFactory.createDataFlowValue(deparenthesizedArgument, type, context);
-        if (!dataFlowValue.isStableIdentifier()) return type;
+        if (!dataFlowValue.isStableIdentifier() && !dataFlowValue.isLocalVariable()) return type;
 
         Set<JetType> possibleTypes = context.dataFlowInfo.getPossibleTypes(dataFlowValue);
         if (possibleTypes.isEmpty()) return type;

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.java

@@ -98,15 +98,15 @@ public boolean isJumpPossible() {
     @Override
     @NotNull
     public Nullability getNullability(@NotNull DataFlowValue key) {
-        if (!key.isStableIdentifier()) return key.getImmanentNullability();
+        if (!key.isStableIdentifier() && !key.isLocalVariable()) return key.getImmanentNullability();
         Nullability nullability = nullabilityInfo.get(key);
         return nullability != null ? nullability :
                parent != null ? parent.getNullability(key) :
                key.getImmanentNullability();
     }
 
     private boolean putNullability(@NotNull Map<DataFlowValue, Nullability> map, @NotNull DataFlowValue value, @NotNull Nullability nullability) {
-        if (!value.isStableIdentifier()) return false;
+        if (!value.isStableIdentifier() && !value.isLocalVariable()) return false;
         map.put(value, nullability);
         return nullability != getNullability(value);
     }

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/SmartCastUtils.java

@@ -179,7 +179,11 @@ public static boolean recordSmartCastIfNecessary(
         JetExpression expression = ((ExpressionReceiver) receiver).getExpression();
         DataFlowValue dataFlowValue = DataFlowValueFactory.createDataFlowValue(receiver, context);
 
-        recordCastOrError(expression, smartCastSubType, context.trace, dataFlowValue.isStableIdentifier(), true);
+        recordCastOrError(expression,
+                          smartCastSubType,
+                          context.trace,
+                          dataFlowValue.isStableIdentifier() || dataFlowValue.isLocalVariable(),
+                          true);
         return true;
     }
 

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DataFlowUtils.java

@@ -199,7 +199,11 @@ public static JetType checkType(
 
         for (JetType possibleType : c.dataFlowInfo.getPossibleTypes(dataFlowValue)) {
             if (JetTypeChecker.DEFAULT.isSubtypeOf(possibleType, c.expectedType)) {
-                SmartCastUtils.recordCastOrError(expression, possibleType, c.trace, dataFlowValue.isStableIdentifier(), false);
+                SmartCastUtils.recordCastOrError(expression,
+                                                 possibleType,
+                                                 c.trace,
+                                                 dataFlowValue.isStableIdentifier() || dataFlowValue.isLocalVariable(),
+                                                 false);
                 return possibleType;
             }
         }

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/DataFlowInfoUtilForCompletion.kt

@@ -24,7 +24,7 @@ import org.jetbrains.kotlin.descriptors.PackageViewDescriptor
 
 fun renderDataFlowValue(value: DataFlowValue): String? {
     // If it is not a stable identifier, there's no point in rendering it
-    if (!value.isStableIdentifier()) return null
+    if (!value.isStableIdentifier() && !value.isLocalVariable()) return null
 
     fun renderId(id: Any?): String? {
         return when (id) {