type equality constraint: accept unbounded/extends wildcards pair; reject unbounded/super

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/TypeEqualityConstraint.java

@@ -55,11 +55,12 @@ public class TypeEqualityConstraint implements ConstraintFormula {
     if (myT instanceof PsiClassType && myS instanceof PsiClassType) {
       final PsiClassType.ClassResolveResult tResult = ((PsiClassType)myT).resolveGenerics();
       final PsiClassType.ClassResolveResult sResult = ((PsiClassType)myS).resolveGenerics();
-      final PsiClass C = tResult.getElement();
-      if (C == sResult.getElement() && C != null) {
+      final PsiClass tClass = tResult.getElement();
+      //equal erasure
+      if (tClass != null && tClass.equals(sResult.getElement())) {
         final PsiSubstitutor tSubstitutor = tResult.getSubstitutor();
         final PsiSubstitutor sSubstitutor = sResult.getSubstitutor();
-        for (PsiTypeParameter typeParameter : C.getTypeParameters()) {
+        for (PsiTypeParameter typeParameter : tClass.getTypeParameters()) {
           final PsiType tSubstituted = tSubstitutor.substitute(typeParameter);
           final PsiType sSubstituted = sSubstitutor.substitute(typeParameter);
           if (tSubstituted != null && sSubstituted != null) {
@@ -73,16 +74,6 @@ public class TypeEqualityConstraint implements ConstraintFormula {
       constraints.add(new TypeEqualityConstraint(((PsiArrayType)myT).getComponentType(), ((PsiArrayType)myS).getComponentType()));
       return true;
     }
-    if (myT instanceof PsiIntersectionType && myS instanceof PsiIntersectionType) {
-      final PsiType[] tConjuncts = ((PsiIntersectionType)myT).getConjuncts();
-      final PsiType[] sConjuncts = ((PsiIntersectionType)myS).getConjuncts();
-      if (sConjuncts.length == tConjuncts.length) {
-        for (int i = 0; i < sConjuncts.length; i++) {
-          constraints.add(new TypeEqualityConstraint(tConjuncts[i], sConjuncts[i]));
-        }
-        return true;
-      }
-    }
 
     if (myT instanceof PsiWildcardType && myS instanceof PsiWildcardType) {
       final PsiType tBound = ((PsiWildcardType)myT).getBound();
@@ -90,6 +81,18 @@ public class TypeEqualityConstraint implements ConstraintFormula {
 
       if (tBound == null && sBound == null) return true;
 
+      if (sBound == null && ((PsiWildcardType)myT).isExtends()) {
+        //extends bound of "?" (Object)
+        constraints.add(new TypeEqualityConstraint(((PsiWildcardType)myS).getExtendsBound(), tBound));
+        return true;
+      }
+
+      if (tBound == null && ((PsiWildcardType)myS).isExtends()) {
+        //extends bound of "?" (Object)
+        constraints.add(new TypeEqualityConstraint(((PsiWildcardType)myT).getExtendsBound(), sBound));
+        return true;
+      }
+
       if (((PsiWildcardType)myT).isExtends() && ((PsiWildcardType)myS).isExtends() || 
           ((PsiWildcardType)myT).isSuper() && ((PsiWildcardType)myS).isSuper()) {
 

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/constraints/EqualityUnboundWildcard.java

@@ -0,0 +1,37 @@
+public class SampleExtendsWildcard {
+  public void highlightsTheBug(Stream<String> stream) {
+    stream.flatMap((Block<?> sink, String element) -> {});
+  }
+
+  public interface Block<B> {
+    void apply(B t);
+  }
+
+  public interface Stream<S> {
+    <R> Stream<R> flatMap(FlatMapper<? super S, R> mapper);
+
+  }
+
+  public interface FlatMapper<F, R> {
+    void flatMapInto(Block<? extends R> sink, F element);
+  }
+}
+
+class SampleSuperWildcard {
+  public void highlightsTheBug(Stream<String> stream) {
+    stream.flatMap((<error descr="Incompatible parameter types in lambda expression">Block<?> sink</error>, String element) -> {});
+  }
+
+  public interface Block<B> {
+    void apply(B t);
+  }
+
+  public interface Stream<S> {
+    <R> Stream<R> flatMap(FlatMapper<? super S, R> mapper);
+
+  }
+
+  public interface FlatMapper<F, R> {
+    void flatMapInto(Block<? super R> sink, F element);
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/ConstraintsInferenceMiscTest.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInsight.daemon.lambda;
+
+import com.intellij.codeInsight.daemon.LightDaemonAnalyzerTestCase;
+import com.intellij.openapi.projectRoots.Sdk;
+import com.intellij.testFramework.IdeaTestUtil;
+import org.jetbrains.annotations.NonNls;
+
+/**
+ * Created by anna on 1/31/14.
+ */
+public class ConstraintsInferenceMiscTest extends LightDaemonAnalyzerTestCase {
+  @NonNls static final String BASE_PATH = "/codeInsight/daemonCodeAnalyzer/lambda/constraints";
+
+  public void testEqualityUnboundWildcard() throws Exception {
+    doTest(false);
+  }
+
+  private void doTest(final boolean checkWarnings) {
+    doTestNewInference(BASE_PATH + "/" + getTestName(false) + ".java", checkWarnings, false);
+  }
+
+  @Override
+  protected Sdk getProjectJDK() {
+    return IdeaTestUtil.getMockJdk18();
+  }
+}