new inference: same parametrization check tweaked (IDEA-130519)

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

@@ -549,7 +549,7 @@ public class InferenceSession {
       final Processor<Pair<PsiType, PsiType>> differentParameterizationProcessor = new Processor<Pair<PsiType, PsiType>>() {
         @Override
         public boolean process(Pair<PsiType, PsiType> pair) {
-          return pair.first == null || pair.second == null || pair.first.equals(pair.second);
+          return pair.first == null || pair.second == null || !TypesDistinctProver.provablyDistinct(pair.first, pair.second);
         }
       };
       if (InferenceIncorporationPhase.findParameterizationOfTheSameGenericClass(bounds, differentParameterizationProcessor)) return true;

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newLambda/SameParametrizationCheckTakesTypeParametersIntoAccount.java

@@ -0,0 +1,28 @@
+import java.util.Optional;
+
+interface Work<T> {
+  T execute();
+}
+
+interface Result {}
+
+class ResultImpl implements Result {}
+
+class Provider {
+  <T> T doWork(Work<T> work) {
+    return work.execute();
+  }
+}
+
+class Main {
+  public static void main(String[] args) {
+    final Provider provider = new Provider();
+    final Optional<Result> result = provider.doWork(() -> {
+      if (args.length > 1) {
+        return Optional.of(new ResultImpl());
+      } else {
+        return Optional.of(new ResultImpl());
+      }
+    });
+  }
+}

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

@@ -134,6 +134,10 @@ public class NewLambdaHighlightingTest extends LightDaemonAnalyzerTestCase {
     doTest();
   }
 
+  public void testSameParametrizationCheckTakesTypeParametersIntoAccount() throws Exception {
+    doTest();
+  }
+
   @Bombed(month = Calendar.OCTOBER, day = 30)
   public void testCheckedExceptionsConstraintsSubstitutions() throws Exception {
     doTest();