IDEADEV-40829 "​Original IntelliJ Cast" should not propose cast that is already present

java/java-impl/src/com/intellij/codeInsight/completion/BasicExpressionCompletionContributor.java

@@ -27,7 +27,9 @@ import com.intellij.psi.*;
 import com.intellij.psi.filters.ContextGetter;
 import com.intellij.psi.filters.element.ExcludeDeclaredFilter;
 import com.intellij.psi.filters.getters.*;
+import com.intellij.psi.scope.BaseScopeProcessor;
 import com.intellij.psi.scope.ElementClassFilter;
+import com.intellij.psi.scope.util.PsiScopesUtil;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.Consumer;
 import com.intellij.util.IncorrectOperationException;
@@ -108,7 +110,7 @@ public class BasicExpressionCompletionContributor extends ExpressionSmartComplet
           }
         }
 
-        processDataflowExpressionTypes(position, expectedType, new Consumer<LookupElement>() {
+        processDataflowExpressionTypes(position, expectedType, result.getPrefixMatcher(), new Consumer<LookupElement>() {
           public void consume(LookupElement decorator) {
             result.addElement(decorator);
           }
@@ -125,11 +127,38 @@ public class BasicExpressionCompletionContributor extends ExpressionSmartComplet
 
   }
 
-  public static void processDataflowExpressionTypes(PsiElement position, @Nullable PsiType expectedType, Consumer<LookupElement> consumer) {
+  public static void processDataflowExpressionTypes(PsiElement position, @Nullable PsiType expectedType, final PrefixMatcher matcher, Consumer<LookupElement> consumer) {
     final PsiExpression context = PsiTreeUtil.getParentOfType(position, PsiExpression.class);
     if (context == null) return;
 
     final Map<PsiExpression,PsiType> map = GuessManager.getInstance(position.getProject()).getControlFlowExpressionTypes(context);
+    if (map.isEmpty()) {
+      return;
+    }
+
+    PsiScopesUtil.treeWalkUp(new BaseScopeProcessor() {
+      public boolean execute(PsiElement element, ResolveState state) {
+        if (element instanceof PsiLocalVariable) {
+          if (!matcher.prefixMatches(((PsiLocalVariable)element).getName())) {
+            return true;
+          }
+
+          final PsiExpression expression = ((PsiLocalVariable)element).getInitializer();
+          if (expression instanceof PsiTypeCastExpression) {
+            PsiTypeCastExpression typeCastExpression = (PsiTypeCastExpression)expression;
+            final PsiExpression operand = typeCastExpression.getOperand();
+            if (operand != null) {
+              final PsiType dfaCasted = map.get(operand);
+              if (dfaCasted != null && dfaCasted.equals(typeCastExpression.getType())) {
+                map.remove(operand);
+              }
+            }
+          }
+        }
+        return true;
+      }
+    }, context, context.getContainingFile());
+
     for (final PsiExpression expression : map.keySet()) {
       final PsiType castType = map.get(expression);
       final PsiType baseType = expression.getType();

java/java-impl/src/com/intellij/codeInsight/completion/ReferenceExpressionCompletionContributor.java

@@ -57,6 +57,18 @@ public class ReferenceExpressionCompletionContributor extends ExpressionSmartCom
   private static final PsiMethodPattern OBJECT_METHOD_PATTERN = psiMethod().withName(
       PsiJavaPatterns.string().oneOf("hashCode", "equals", "finalize", "wait", "notify", "notifyAll", "getClass", "clone", "toString")).
       definedInClass(CommonClassNames.JAVA_LANG_OBJECT);
+  private static final PrefixMatcher TRUE_MATCHER = new PrefixMatcher("") {
+    @Override
+    public boolean prefixMatches(@NotNull String name) {
+      return true;
+    }
+
+    @NotNull
+    @Override
+    public PrefixMatcher cloneWithPrefix(@NotNull String prefix) {
+      return this;
+    }
+  };
 
   @NotNull 
   private static ElementFilter getReferenceFilter(PsiElement element, boolean allowRecursion) {
@@ -111,7 +123,7 @@ public class ReferenceExpressionCompletionContributor extends ExpressionSmartCom
 
           if (isSecond) {
             if (!psiElement().afterLeaf(".").accepts(element)) {
-              BasicExpressionCompletionContributor.processDataflowExpressionTypes(element, null, new Consumer<LookupElement>() {
+              BasicExpressionCompletionContributor.processDataflowExpressionTypes(element, null, TRUE_MATCHER, new Consumer<LookupElement>() {
                 public void consume(LookupElement baseItem) {
                   addSecondCompletionVariants(element, reference, baseItem, parameters, result);
                 }

java/java-impl/src/com/intellij/codeInsight/guess/impl/GuessManagerImpl.java

@@ -162,10 +162,10 @@ public class GuessManagerImpl extends GuessManager {
     getTopmostBlock(forPlace).accept(new JavaRecursiveElementWalkingVisitor() {
       @Override
       public void visitTypeCastExpression(PsiTypeCastExpression expression) {
-        final PsiTypeElement castType = expression.getCastType();
+        final PsiType castType = expression.getType();
         final PsiExpression operand = expression.getOperand();
         if (operand != null && castType != null) {
-          allCasts.put(operand, castType.getType());
+          allCasts.put(operand, castType);
         }
         super.visitTypeCastExpression(expression);
       }
@@ -346,8 +346,7 @@ public class GuessManagerImpl extends GuessManager {
           if (pattern.parameterIndex < 0){ // return value
             if (methodCall.getParent() instanceof PsiTypeCastExpression &&
                 (rangeToIgnore == null || !rangeToIgnore.contains(methodCall.getTextRange()))) {
-              final PsiTypeElement castType = ((PsiTypeCastExpression)methodCall.getParent()).getCastType();
-              return castType == null ? null : castType.getType();
+              return ((PsiTypeCastExpression)methodCall.getParent()).getType();
             }
           }
           else{