[groovy] do not allow modifier 'static' on toplevel classes (IDEA-162294)

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/GroovyBundle.properties

@@ -180,6 +180,7 @@ illegal.combination.of.modifiers=Illegal combination of modifiers
 illegal.combination.of.modifiers.abstract.and.final=Illegal combination of modifiers 'abstract' and 'final'
 modifier.volatile.not.allowed.here=Modifier 'volatile' not allowed here
 modifier.transient.not.allowed.here=Modifier 'transient' not allowed here
+modifier.0.not.allowed=Modifier ''{0}'' not allowed here
 intarface.cannot.have.modifier.final=Interface cannot have modifier 'final'
 script.method.cannot.have.modifier.abstract=Script method cannot have modifier 'abstract'
 script.cannot.have.modifier.native=Script cannot have modifier 'native'

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/annotator/GroovyAnnotator.java

@@ -1906,6 +1906,12 @@ public class GroovyAnnotator extends GroovyElementVisitor {
     if (typeDefinition.isInterface()) {
       checkModifierIsNotAllowed(modifiersList, PsiModifier.FINAL, GroovyBundle.message("intarface.cannot.have.modifier.final"), holder);
     }
+
+    if (GroovyConfigUtils.getInstance().isVersionAtLeast(typeDefinition, GroovyConfigUtils.GROOVY1_8)) {
+      if (typeDefinition.getContainingClass() == null && !(typeDefinition instanceof GrTraitTypeDefinition)) {
+        checkModifierIsNotAllowed(modifiersList, PsiModifier.STATIC, holder);
+      }
+    }
   }
 
   private static void checkDuplicateModifiers(AnnotationHolder holder, @NotNull GrModifierList list, PsiMember member) {

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/annotator/util.kt

@@ -38,6 +38,12 @@ internal fun checkVariableModifiers(holder: AnnotationHolder, variableDeclaratio
   }
 }
 
+internal fun checkModifierIsNotAllowed(modifierList: GrModifierList,
+                                       @GrModifierConstant modifier: String,
+                                       holder: AnnotationHolder) {
+  checkModifierIsNotAllowed(modifierList, modifier, GroovyBundle.message("modifier.0.not.allowed", modifier), holder)
+}
+
 internal fun checkModifierIsNotAllowed(modifierList: GrModifierList,
                                        @GrModifierConstant modifier: String,
                                        message: String?,

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/Groovy16HighlightingTest.groovy

@@ -62,4 +62,13 @@ class Groovy16HighlightingTest extends LightCodeInsightFixtureTestCase {
   void testSlashyStrings() { doTest() }
 
   void testDiamonds() { doTest() }
+
+  void 'test static modifier on toplevel definition is allowed'() {
+    myFixture.with {
+      configureByText '_.groovy', '''\
+static class A {}
+static interface A {} 
+'''
+    }
+  }
 }

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/Groovy23HighlightingTest.groovy

@@ -17,7 +17,6 @@ package org.jetbrains.plugins.groovy.lang.highlighting
 
 import com.intellij.codeInsight.generation.OverrideImplementExploreUtil
 import com.intellij.codeInspection.InspectionProfileEntry
-import com.intellij.psi.PsiElement
 import com.intellij.psi.util.PsiTreeUtil
 import com.intellij.testFramework.LightProjectDescriptor
 import org.jetbrains.annotations.NotNull
@@ -270,5 +269,13 @@ class A {
     }
   }
 
+  void 'test static modifier on toplevel definition (not trait) is not allowed'() {
+    testHighlighting '''\
+<error descr="Modifier 'static' not allowed here">static</error> class A {}
+<error descr="Modifier 'static' not allowed here">static</error> interface I {}
+static trait T {}
+'''
+  }
+
   final InspectionProfileEntry[] customInspections = [new GroovyAssignabilityCheckInspection(), new GrUnresolvedAccessInspection()]
 }