From e9e7ce005dac03c88439a1cfc76556f1c06287e4 Mon Sep 17 00:00:00 2001
From: anna <Anna.Kozlova@jetbrains.com>
Date: Fri, 3 May 2013 16:15:28 +0200
Subject: [PATCH] forbid casting to nested wildcards (IDEA-71007)

---
 .../intellij/psi/util/TypeConversionUtil.java | 11 +++++--
 .../psi/util/TypesDistinctProver.java         |  3 +-
 .../DisableCastingToNestedWildcards.java      | 32 +++++++++++++++++++
 .../daemon/GenericsHighlightingTest.java      |  4 +++
 4 files changed, 47 insertions(+), 3 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/DisableCastingToNestedWildcards.java

diff --git a/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java b/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java
index 672a01334f47..9cce64d95310 100644
--- a/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java
+++ b/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java
@@ -325,7 +325,7 @@ public class TypeConversionUtil {
     PsiClass[] supers = derived.getSupers();
     if (manager.areElementsEquivalent(base, derived)) {
       derivedSubstitutor = getSuperClassSubstitutor(derived, derived, derivedSubstitutor);
-      return areSameArgumentTypes(derived, baseResult.getSubstitutor(), derivedSubstitutor);
+      return areSameArgumentTypes(derived, baseResult.getSubstitutor(), derivedSubstitutor, 1);
     }
     else if (base.isInheritor(derived, true)) {
       derivedSubstitutor = getSuperClassSubstitutor(derived, derived, derivedSubstitutor);
@@ -355,11 +355,18 @@ public class TypeConversionUtil {
   }
 
   private static boolean areSameArgumentTypes(PsiClass aClass, PsiSubstitutor substitutor1, PsiSubstitutor substitutor2) {
+    return areSameArgumentTypes(aClass, substitutor1, substitutor2, 0);
+  }
+
+  private static boolean areSameArgumentTypes(PsiClass aClass,
+                                              PsiSubstitutor substitutor1,
+                                              PsiSubstitutor substitutor2,
+                                              int level) {
     for (PsiTypeParameter typeParameter : PsiUtil.typeParametersIterable(aClass)) {
       PsiType typeArg1 = substitutor1.substitute(typeParameter);
       PsiType typeArg2 = substitutor2.substitute(typeParameter);
       if (typeArg1 == null || typeArg2 == null) return true;
-      if (TypesDistinctProver.provablyDistinct(typeArg1, typeArg2)) return false;
+      if (TypesDistinctProver.provablyDistinct(typeArg1, typeArg2, level)) return false;
 
       final PsiClass class1 = PsiUtil.resolveClassInType(typeArg1);
       if (class1 instanceof PsiTypeParameter) {
diff --git a/java/java-psi-api/src/com/intellij/psi/util/TypesDistinctProver.java b/java/java-psi-api/src/com/intellij/psi/util/TypesDistinctProver.java
index 5d2c6aab7467..04bd3481bf27 100644
--- a/java/java-psi-api/src/com/intellij/psi/util/TypesDistinctProver.java
+++ b/java/java-psi-api/src/com/intellij/psi/util/TypesDistinctProver.java
@@ -35,7 +35,7 @@ public class TypesDistinctProver {
     return provablyDistinct(type1, type2, 0);
   }
 
-  private static boolean provablyDistinct(PsiType type1, PsiType type2, int level) {
+  protected static boolean provablyDistinct(PsiType type1, PsiType type2, int level) {
     if (type1 instanceof PsiClassType && ((PsiClassType)type1).resolve() instanceof PsiTypeParameter) return false;
     if (type2 instanceof PsiClassType && ((PsiClassType)type2).resolve() instanceof PsiTypeParameter) return false;
     if (type1 instanceof PsiWildcardType) {
@@ -43,6 +43,7 @@ public class TypesDistinctProver {
         return provablyDistinct((PsiWildcardType)type1, (PsiWildcardType)type2);
       }
 
+      if (level > 1) return true;
       if (type2 instanceof PsiCapturedWildcardType) {
         return ((PsiWildcardType)type1).isExtends() && level > 0 ||
                provablyDistinct((PsiWildcardType)type1, ((PsiCapturedWildcardType)type2).getWildcard());
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/DisableCastingToNestedWildcards.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/DisableCastingToNestedWildcards.java
new file mode 100644
index 000000000000..9c076abce2ac
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/DisableCastingToNestedWildcards.java
@@ -0,0 +1,32 @@
+import java.util.List;
+
+public class Test {
+
+    interface P {
+
+    }
+
+    public abstract class AP implements P {
+
+    }
+
+    public class AP1 extends AP {
+
+    }
+
+    public class AP2 extends AP {
+
+    }
+
+    private static final List<Class<AP1>> AP_LIST = listOf(AP1.class);
+
+
+    private static <T> List<T> listOf(T... ts) {
+        return null;
+    }
+
+    public static void test() {
+        List<Class<? extends AP>> apList1 = <error descr="Inconvertible types; cannot cast 'java.util.List<java.lang.Class<Test.AP1>>' to 'java.util.List<java.lang.Class<? extends Test.AP>>'">(List<Class<? extends AP>>) AP_LIST</error>;
+        List<Class<? super AP1>> apList2 = <error descr="Inconvertible types; cannot cast 'java.util.List<java.lang.Class<Test.AP1>>' to 'java.util.List<java.lang.Class<? super Test.AP1>>'">(List<Class<? super AP1>>) AP_LIST</error>;
+    }
+}
diff --git a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/GenericsHighlightingTest.java b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/GenericsHighlightingTest.java
index de9a8363ca8e..2012ad3e4463 100644
--- a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/GenericsHighlightingTest.java
+++ b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/GenericsHighlightingTest.java
@@ -239,6 +239,10 @@ public class GenericsHighlightingTest extends LightDaemonAnalyzerTestCase {
     doTest(LanguageLevel.JDK_1_7, JavaSdkVersion.JDK_1_7, false);
   }
 
+  public void testDisableCastingToNestedWildcards() throws Exception {
+    doTest5(false);
+  }
+
   public void testBooleanInferenceFromIfCondition() throws Exception {
     doTest5(false);
   }