add type cast as fix for unresolved calls (IDEA-185569)

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/AddTypeCastFix.java

@@ -16,11 +16,14 @@
 
 package com.intellij.codeInsight.daemon.impl.quickfix;
 
+import com.intellij.codeInsight.daemon.QuickFixActionRegistrar;
 import com.intellij.codeInsight.daemon.QuickFixBundle;
+import com.intellij.codeInsight.guess.GuessManager;
 import com.intellij.codeInsight.intention.HighPriorityAction;
 import com.intellij.codeInspection.LocalQuickFixAndIntentionActionOnPsiElement;
 import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.CodeStyleManager;
 import com.intellij.psi.codeStyle.JavaCodeStyleManager;
@@ -30,20 +33,28 @@ import com.intellij.psi.util.TypeConversionUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.List;
+
 import static com.intellij.util.ObjectUtils.assertNotNull;
 
 public class AddTypeCastFix extends LocalQuickFixAndIntentionActionOnPsiElement implements HighPriorityAction {
   private final PsiType myType;
+  private final String myName;
 
   public AddTypeCastFix(@NotNull PsiType type, @NotNull PsiExpression expression) {
+    this(type, expression, "add.typecast.text");
+  }
+
+  public AddTypeCastFix(@NotNull PsiType type, @NotNull PsiExpression expression, String messageKey) {
     super(expression);
     myType = type;
+    myName = QuickFixBundle.message(messageKey, type.isValid() ? type.getCanonicalText() : "");
   }
 
   @Override
   @NotNull
   public String getText() {
-    return QuickFixBundle.message("add.typecast.text", myType.isValid() ? myType.getCanonicalText() : "");
+    return myName;
   }
 
   @Override
@@ -118,4 +129,27 @@ public class AddTypeCastFix extends LocalQuickFixAndIntentionActionOnPsiElement
 
     return typeCast;
   }
+
+  public static void registerFix(QuickFixActionRegistrar registrar,
+                                 PsiExpression qualifier,
+                                 PsiJavaCodeReferenceElement ref, 
+                                 TextRange fixRange) {
+    String referenceName = ref.getReferenceName();
+    if (referenceName == null) return;
+    PsiElement gParent = ref.getParent();
+    List<PsiType> conjuncts = GuessManager.getInstance(qualifier.getProject()).getControlFlowExpressionTypeConjuncts(qualifier);
+    for (PsiType conjunct : conjuncts) {
+      PsiClass psiClass = PsiUtil.resolveClassInType(conjunct);
+      if (psiClass == null) continue;
+      if (gParent instanceof PsiMethodCallExpression) {
+        if (psiClass.findMethodsByName(referenceName).length == 0) {
+          continue;
+        }
+      }
+      else if (psiClass.findFieldByName(referenceName, true) == null) {
+        continue;
+      }
+      registrar.register(fixRange, new AddTypeCastFix(conjunct, qualifier, "add.qualifier.typecast.text"), null);
+    }
+  }
 }

java/java-analysis-impl/src/messages/QuickFixBundle.properties

@@ -29,6 +29,7 @@ add.runtime.exception.to.throws.text=Add runtime exception(s) to method signatur
 add.runtime.exception.to.throws.family=Add Runtime Exception to Method Signature
 add.typecast.family=Add TypeCast
 add.typecast.text=Cast to ''{0}''
+add.qualifier.typecast.text=Cast qualifier to ''{0}''
 add.docTag.to.custom.tags=Add {0} to custom tags
 fix.javadoc.family=Fix Javadoc
 adjust.package.family=Adjust Package Name

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/DefaultQuickFixProvider.java

@@ -49,9 +49,13 @@ public class DefaultQuickFixProvider extends UnresolvedReferenceQuickFixProvider
       PsiReferenceExpression refExpr = (PsiReferenceExpression)ref;
 
       registrar.register(new RenameWrongRefFix(refExpr));
-      if (!ref.isQualified()) {
+      PsiExpression qualifier = ((PsiReferenceExpression)ref).getQualifierExpression();
+      if (qualifier == null) {
         registrar.register(fixRange, new BringVariableIntoScopeFix(refExpr), null);
       }
+      else {
+        AddTypeCastFix.registerFix(registrar, qualifier, ref, fixRange);
+      }
 
       for (IntentionAction action : createVariableActions(refExpr)) {
         registrar.register(fixRange, action, null);

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/addTypeCast/afterCastFromControlFlow.java

@@ -0,0 +1,8 @@
+// "Cast qualifier to 'java.lang.String'" "true"
+class Test {
+  void m(Object o) {
+    if (o instanceof String) {
+      System.out.println(((String) o).length());
+    }
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/addTypeCast/beforeCastFromControlFlow.java

@@ -0,0 +1,8 @@
+// "Cast qualifier to 'java.lang.String'" "true"
+class Test {
+  void m(Object o) {
+    if (o instanceof String) {
+      System.out.println(<caret>o.length());
+    }
+  }
+}