Retain data flow info after multi-declaration

#KT-2825 In Progress

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingVisitorForStatements.java

@@ -137,14 +137,14 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
             context.trace.report(INITIALIZER_REQUIRED_FOR_MULTIDECLARATION.on(multiDeclaration));
             return JetTypeInfo.create(null, context.dataFlowInfo);
         }
-        final ExpressionReceiver expressionReceiver = ExpressionTypingUtils.getExpressionReceiver(facade, initializer,
-                                                                                                  context.replaceExpectedType(
-                                                                                                          TypeUtils.NO_EXPECTED_TYPE));
+        final ExpressionReceiver expressionReceiver =
+                ExpressionTypingUtils.getExpressionReceiver(facade, initializer, context.replaceExpectedType(TypeUtils.NO_EXPECTED_TYPE));
+        DataFlowInfo dataFlowInfo = facade.getTypeInfo(initializer, context).getDataFlowInfo();
         if (expressionReceiver == null) {
-            return JetTypeInfo.create(null, context.dataFlowInfo);
+            return JetTypeInfo.create(null, dataFlowInfo);
         }
         ExpressionTypingUtils.defineLocalVariablesFromMultiDeclaration(scope, multiDeclaration, expressionReceiver, initializer, context);
-        return DataFlowUtils.checkStatementType(multiDeclaration, context, context.dataFlowInfo);
+        return DataFlowUtils.checkStatementType(multiDeclaration, context, dataFlowInfo);
     }
 
     @Override

compiler/testData/diagnostics/tests/dataFlowInfoTraversal/MultiDeclaration.kt

@@ -0,0 +1,7 @@
+fun Int.component1() = "a"
+
+fun foo(a: Number) {
+    val (x) = a as Int
+    a : Int
+    x : String
+}

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -1241,6 +1241,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/dataFlowInfoTraversal/IfThenElseBothInvalid.kt");
             }
             
+            @TestMetadata("MultiDeclaration.kt")
+            public void testMultiDeclaration() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/dataFlowInfoTraversal/MultiDeclaration.kt");
+            }
+            
             @TestMetadata("ObjectExpression.kt")
             public void testObjectExpression() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/dataFlowInfoTraversal/ObjectExpression.kt");