[java] highlights inaccessible or ambiguous packages

java/java-impl/src/com/intellij/psi/impl/JavaPlatformModuleSystem.kt

@@ -57,9 +57,13 @@ class JavaPlatformModuleSystem : JavaModuleSystemEx {
         if (module != null) {
           val test = index.isInTestSourceContent(useVFile)
           val dirs = target.getDirectories(module.getModuleWithDependenciesAndLibrariesScope(test))
-          if (dirs.size == 1) {
-            return checkAccess(dirs[0], useFile, target.qualifiedName, quick)
+          if (dirs.isEmpty()) {
+            return if (quick) ERR else ErrorWithFixes(JavaErrorMessages.message("package.not.found", target.qualifiedName))
           }
+          val error = checkAccess(dirs[0], useFile, target.qualifiedName, quick)
+          return if (error == null ||
+                     dirs.size > 1 && dirs.asSequence().drop(1).any { checkAccess(it, useFile, target.qualifiedName, true) == null }) null
+                 else error
         }
       }
     }

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/ModuleCompletionTest.kt

@@ -58,12 +58,12 @@ class ModuleCompletionTest : LightJava9ModulesCodeInsightFixtureTestCase() {
   fun testExportsToUnambiguous() = complete("module M { exports pkg.other to M<caret> }", "module M { exports pkg.other to M2<caret> }")
 
   fun testUsesPrefixed() = complete("module M { uses p<caret> }", "module M { uses pkg.<caret> }")
-  fun testUsesQualified1() = variants("module M { uses pkg.<caret> }", "main", "other", "empty", "lib2")
+  fun testUsesQualified1() = variants("module M { uses pkg.<caret> }", "main", "other", "empty")
   fun testUsesQualified2() = variants("module M { uses pkg.main.<caret> }", "MyAnno", "MySvc")
   fun testUsesUnambiguous() = complete("module M { uses pkg.main.MS<caret> }", "module M { uses pkg.main.MySvc<caret> }")
 
   fun testProvidesPrefixed() = complete("module M { provides p<caret> }", "module M { provides pkg.<caret> }")
-  fun testProvidesQualified1() = variants("module M { provides pkg.<caret> }", "main", "other", "empty", "lib2")
+  fun testProvidesQualified1() = variants("module M { provides pkg.<caret> }", "main", "other", "empty")
   fun testProvidesQualified2() = variants("module M { provides pkg.main.<caret> }", "MyAnno", "MySvc")
   fun testProvidesUnambiguous() = complete("module M { provides pkg.main.MS<caret> }", "module M { provides pkg.main.MySvc<caret> }")
   fun testProvidesWith() = complete("module M { provides pkg.main.MySvc <caret> }", "module M { provides pkg.main.MySvc with <caret> }")

java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/ModuleHighlightingTest.kt

@@ -216,10 +216,13 @@ class ModuleHighlightingTest : LightJava9ModulesCodeInsightFixtureTestCase() {
     addFile("module-info.java", "module M2 { exports pkg.m2; exports pkg.m2.impl to close.friends.only; }", M2)
     addFile("pkg/m2/C2.java", "package pkg.m2;\npublic class C2 { }", M2)
     addFile("pkg/m2/impl/C2Impl.java", "package pkg.m2.impl;\nimport pkg.m2.C2;\npublic class C2Impl { public static int I; public static C2 make() {} }", M2)
+    addFile("pkg/sub/C2X.java", "package pkg.sub;\npublic class C2X { }", M2)
+    addFile("pkg/unreachable/C3.java", "package pkg.unreachable;\npublic class C3 { }", M3)
     addFile("pkg/m4/C4.java", "package pkg.m4;\npublic class C4 { }", M4)
     addFile("module-info.java", "module M5 { exports pkg.m5; }", M5)
     addFile("pkg/m5/C5.java", "package pkg.m5;\npublic class C5 { }", M5)
     addFile("module-info.java", "module M6 { requires transitive M7; }", M6)
+    addFile("pkg/sub/C6X.java", "package pkg.sub;\npublic class C6X { }", M6)
     addFile("module-info.java", "module M7 { exports pkg.m7; }", M7)
     addFile("pkg/m7/C7.java", "package pkg.m7;\npublic class C7 { }", M7)
     highlight("test.java", """
@@ -230,6 +233,8 @@ class ModuleHighlightingTest : LightJava9ModulesCodeInsightFixtureTestCase() {
         import <error descr="Package 'pkg.m4' is declared in the unnamed module, but module 'M' does not read it">pkg.m4</error>.C4;
         import <error descr="Package 'pkg.m5' is declared in module 'M5', but module 'M' does not read it">pkg.m5</error>.C5;
         import pkg.m7.C7;
+        import <error descr="Package 'pkg.sub' is declared in module 'M2', which does not export it to module 'M'">pkg.sub</error>.*;
+        import <error descr="Package not found: pkg.unreachable">pkg.unreachable</error>.*;
 
         import pkg.lib1.LC1;
         import <error descr="Package 'pkg.lib1.impl' is declared in module 'lib.named', which does not export it to module 'M'">pkg.lib1.impl</error>.LC1Impl;