conditional: ensure to convert type from parent to ll >= 1.8 so assignments would be correct, etc (IDEA-161854)

java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiConditionalExpressionImpl.java

@@ -71,7 +71,11 @@ public class PsiConditionalExpressionImpl extends ExpressionPsiElement implement
         !MethodCandidateInfo.ourOverloadGuard.currentStack().contains(PsiUtil.skipParenthesizedExprUp(this.getParent()))) {
       //15.25.3 Reference Conditional Expressions 
       // The type of a poly reference conditional expression is the same as its target type.
-      return InferenceSession.getTargetType(this);
+      final PsiType targetType = InferenceSession.getTargetType(this);
+      if (targetType instanceof PsiClassType) {
+        return ((PsiClassType)targetType).setLanguageLevel(PsiUtil.getLanguageLevel(this));
+      }
+      return targetType;
     }
 
     final int typeRank1 = TypeConversionUtil.getTypeRank(type1);

java/java-tests/testData/codeInsight/multipleJdks/java3/p/ConditionalAssignedToJava3Object.java

@@ -0,0 +1,4 @@
+package p;
+class A {
+  public void foo(Object o) {}
+}

java/java-tests/testData/codeInsight/multipleJdks/java8/p/ConditionalAssignedToJava3Object.java

@@ -0,0 +1,6 @@
+package p;
+class B {
+  void bar(A a) {
+    a.foo(true ? "1" : 1);
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/MultipleJdksHighlightingTest.java

@@ -253,6 +253,14 @@ public class MultipleJdksHighlightingTest extends UsefulTestCase {
     assertContainsElements(MethodReferencesSearch.search(method).findAll(), ref);
   }
 
+  public void testConditionalAssignedToJava3Object() throws Exception {
+    ModuleRootModificationUtil.addDependency(myJava8Module, myJava3Module);
+    final String name = getTestName(false);
+    myFixture.copyFileToProject("java3/p/" + name + ".java");
+    myFixture.configureByFiles("java8/p/" + name + ".java");
+    myFixture.checkHighlighting();
+  }
+
   private void doTestWithoutLibrary() {
     final String name = getTestName(false);
     myFixture.configureByFiles("java7/p/" + name + ".java", "java8/p/" + name + ".java");