check function type's parameters/return type accessibility (IDEA-181036)

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java

@@ -334,7 +334,7 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
                          .descriptionAndTooltip(notFunctionalMessage).create());
         }
         else {
-          checkFunctionalInterfaceTypeAccessible(expression, functionalInterfaceType);
+          checkFunctionalInterfaceTypeAccessible(expression, functionalInterfaceType, true);
         }
       }
       else if (LambdaUtil.getFunctionalInterfaceType(expression, true) != null) {
@@ -1372,7 +1372,7 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
         }
       }
       if (!myHolder.hasErrorResults()) {
-        checkFunctionalInterfaceTypeAccessible(expression, functionalInterfaceType);
+        checkFunctionalInterfaceTypeAccessible(expression, functionalInterfaceType, true);
       }
       if (!myHolder.hasErrorResults()) {
         String errorMessage = PsiMethodReferenceUtil.checkMethodReferenceContext(expression);
@@ -1474,7 +1474,8 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
   // 15.13 | 15.27
   // It is a compile-time error if any class or interface mentioned by either U or the function type of U
   // is not accessible from the class or interface in which the method reference expression appears.
-  private void checkFunctionalInterfaceTypeAccessible(@NotNull PsiFunctionalExpression expression, PsiType functionalInterfaceType) {
+  private boolean checkFunctionalInterfaceTypeAccessible(@NotNull PsiFunctionalExpression expression, PsiType functionalInterfaceType,
+                                                         boolean checkFunctionalTypeSignature) {
     PsiClassType.ClassResolveResult resolveResult = PsiUtil.resolveGenericsClassInType(functionalInterfaceType);
     PsiClass psiClass = resolveResult.getElement();
     if (psiClass != null) {
@@ -1486,13 +1487,25 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
         if (problem.second != null) {
           problem.second.forEach(fix -> QuickFixAction.registerQuickFixAction(info, fix));
         }
+        return true;
       }
       else {
         for (PsiType type : resolveResult.getSubstitutor().getSubstitutionMap().values()) {
-          checkFunctionalInterfaceTypeAccessible(expression, type);
+          if (checkFunctionalInterfaceTypeAccessible(expression, type, false)) return true;
+        }
+
+        PsiMethod psiMethod = checkFunctionalTypeSignature ? LambdaUtil.getFunctionalInterfaceMethod(resolveResult) : null;
+        if (psiMethod != null) {
+          PsiSubstitutor substitutor = LambdaUtil.getSubstitutor(psiMethod, resolveResult);
+          for (PsiParameter parameter : psiMethod.getParameterList().getParameters()) {
+            if (checkFunctionalInterfaceTypeAccessible(expression, substitutor.substitute(parameter.getType()), false)) return true;
+          }
+
+          if (checkFunctionalInterfaceTypeAccessible(expression, substitutor.substitute(psiMethod.getReturnType()), false)) return true;
         }
       }
     }
+    return false;
   }
 
   @Override

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advFixture/InaccessibleFunctionalTypeParameter.java

@@ -0,0 +1,9 @@
+package p;
+import test.*;
+
+class Test {
+  {
+    I i = <error descr="'test.A' is not public in 'test'. Cannot be accessed from outside package">(a) -> {}</error>;
+    J j = <error descr="'test.A' is not public in 'test'. Cannot be accessed from outside package">() -> null</error>;
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/LightAdvHighlightingFixtureTest.java

@@ -48,6 +48,15 @@ public class LightAdvHighlightingFixtureTest extends LightCodeInsightFixtureTest
     assertNull(ReferencesSearch.search(aClass).findFirst());
   }
 
+  public void testInaccessibleFunctionalTypeParameter() {
+    myFixture.addClass("package test; class A {}");
+    myFixture.addClass("package test; public interface I { void m(A a);}");
+    myFixture.addClass("package test; public interface J { A m();}");
+
+    myFixture.configureByFile(getTestName(false) + ".java");
+    myFixture.checkHighlighting();
+  }
+
   public void testBoundsPromotionWithCapturedWildcards() {
     myFixture.addClass("package a; public interface Provider<A> {}");
     myFixture.addClass("package b; public interface Provider<B> {}");