J2K: inlining intermediate variable after removing type cast

idea/src/org/jetbrains/kotlin/idea/j2k/J2kPostProcessor.kt

@@ -17,6 +17,8 @@
 package org.jetbrains.kotlin.idea.j2k
 
 import com.intellij.psi.PsiElement
+import com.intellij.psi.search.LocalSearchScope
+import com.intellij.psi.search.searches.ReferencesSearch
 import org.jetbrains.kotlin.diagnostics.Diagnostic
 import org.jetbrains.kotlin.diagnostics.Errors
 import org.jetbrains.kotlin.idea.caches.resolve.analyzeFullyAndGetResult
@@ -39,7 +41,17 @@ public class J2kPostProcessor(override val contextToAnalyzeIn: PsiElement) : Pos
         val psiElement = problem.getPsiElement()
         return when (problem.getFactory()) {
             Errors.USELESS_CAST, Errors.USELESS_CAST_STATIC_ASSERT_IS_FINE -> { ->
-                RemoveRightPartOfBinaryExpressionFix(psiElement as JetBinaryExpressionWithTypeRHS, "").invoke()
+                val expression = RemoveRightPartOfBinaryExpressionFix(psiElement as JetBinaryExpressionWithTypeRHS, "").invoke()
+
+                val variable = expression.getParent() as? JetProperty
+                if (variable != null && expression == variable.getInitializer() && variable.isLocal()) {
+                    val refs = ReferencesSearch.search(variable, LocalSearchScope(variable.getContainingFile())).findAll()
+                    for (ref in refs) {
+                        val usage = ref.getElement() as? JetSimpleNameExpression ?: continue
+                        usage.replace(expression)
+                    }
+                    variable.delete()
+                }
             }
 
             else -> super.fixForProblem(problem)

idea/src/org/jetbrains/kotlin/idea/quickfix/RemoveRightPartOfBinaryExpressionFix.java

@@ -48,21 +48,24 @@ public class RemoveRightPartOfBinaryExpressionFix<T extends JetExpression> exten
         invoke();
     }
 
-    public void invoke() throws IncorrectOperationException {
-        PsiElement newElement = null;
+    @NotNull
+    public JetExpression invoke() throws IncorrectOperationException {
+        JetExpression newExpression = null;
 
         if (element instanceof JetBinaryExpression) {
             //noinspection ConstantConditions
-            newElement = element.replace(((JetBinaryExpression) element.copy()).getLeft());
+            newExpression = (JetExpression) element.replace(((JetBinaryExpression) element.copy()).getLeft());
         }
         else if (element instanceof JetBinaryExpressionWithTypeRHS) {
-            newElement = element.replace(((JetBinaryExpressionWithTypeRHS) element.copy()).getLeft());
+            newExpression = (JetExpression) element.replace(((JetBinaryExpressionWithTypeRHS) element.copy()).getLeft());
         }
 
-        PsiElement parent = newElement != null ? newElement.getParent() : null;
+        PsiElement parent = newExpression != null ? newExpression.getParent() : null;
         if (parent instanceof JetParenthesizedExpression && JetPsiUtil.areParenthesesUseless((JetParenthesizedExpression) parent)) {
-            parent.replace(newElement);
+            newExpression = (JetExpression) parent.replace(newExpression);
         }
+
+        return newExpression;
     }
 
     public static JetSingleIntentionActionFactory createRemoveCastFactory() {

j2k/testData/fileOrElement/codeSimplifications/RedundantTypeCastAndInline.java

@@ -0,0 +1,11 @@
+import java.lang.String;
+
+class C {
+    void foo(Object o) {
+        if (o instanceof String) {
+            String s = (String) o;
+            int l = s.length();
+            String substring = s.substring(l - 2);
+        }
+    }
+}

j2k/testData/fileOrElement/codeSimplifications/RedundantTypeCastAndInline.kt

@@ -0,0 +1,8 @@
+class C {
+    fun foo(o: Any) {
+        if (o is String) {
+            val l = o.length()
+            val substring = o.substring(l - 2)
+        }
+    }
+}

j2k/tests/org/jetbrains/kotlin/j2k/JavaToKotlinConverterForWebDemoTestGenerated.java

@@ -1005,6 +1005,12 @@ public class JavaToKotlinConverterForWebDemoTestGenerated extends AbstractJavaTo
             String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/codeSimplifications/RedundantTypeCast.java");
             doTest(fileName);
         }
+
+        @TestMetadata("RedundantTypeCastAndInline.java")
+        public void testRedundantTypeCastAndInline() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/codeSimplifications/RedundantTypeCastAndInline.java");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("j2k/testData/fileOrElement/comments")

j2k/tests/org/jetbrains/kotlin/j2k/JavaToKotlinConverterSingleFileTestGenerated.java

@@ -1005,6 +1005,12 @@ public class JavaToKotlinConverterSingleFileTestGenerated extends AbstractJavaTo
             String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/codeSimplifications/RedundantTypeCast.java");
             doTest(fileName);
         }
+
+        @TestMetadata("RedundantTypeCastAndInline.java")
+        public void testRedundantTypeCastAndInline() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/codeSimplifications/RedundantTypeCastAndInline.java");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("j2k/testData/fileOrElement/comments")