Java inspection: Handle static fields in EqualsReplaceableByObjectsCallInspection (IDEA-161076)

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/migration/EqualsReplaceableByObjectsCallInspection.java

@@ -259,18 +259,30 @@ public class EqualsReplaceableByObjectsCallInspection extends BaseInspection {
     if (expression instanceof PsiReferenceExpression) {
       final PsiReferenceExpression referenceExpression = (PsiReferenceExpression)expression;
       final String referenceName = referenceExpression.getReferenceName();
-      if (referenceName != null && referenceExpression.resolve() instanceof PsiVariable) {
-        final PsiExpression qualifierExpression = ParenthesesUtils.stripParentheses(referenceExpression.getQualifierExpression());
-        if (qualifierExpression == null) {
-          return referenceName;
+      if (referenceName != null) {
+        final PsiElement resolved = referenceExpression.resolve();
+        if (resolved instanceof PsiVariable || resolved instanceof PsiClass) {
+          final PsiExpression qualifierExpression = ParenthesesUtils.stripParentheses(referenceExpression.getQualifierExpression());
+          if (qualifierExpression == null) {
+            return referenceName;
+          }
+          final String qualifierName = getQualifiedVariableName(qualifierExpression);
+          return qualifierName != null ? qualifierName + "." + referenceName : null;
         }
-        final String qualifierName = getQualifiedVariableName(qualifierExpression);
-        return qualifierName != null ? qualifierName + "." + referenceName : null;
       }
     }
     else if (expression instanceof PsiQualifiedExpression) {
       final PsiJavaCodeReferenceElement qualifier = ((PsiQualifiedExpression)expression).getQualifier();
-      final String name = expression instanceof PsiThisExpression ? "this" : "super";
+      final String name;
+      if (expression instanceof PsiThisExpression) {
+        name = "this";
+      }
+      else if (expression instanceof PsiSuperExpression) {
+        name = "super";
+      }
+      else {
+        return null;
+      }
       return qualifier != null ? qualifier.getQualifiedName() + "." + name : name;
     }
     return null;

plugins/InspectionGadgets/test/com/siyeh/igfixes/migration/equals_replaceable_by_objects_call/StaticField.after.java

@@ -0,0 +1,10 @@
+import java.util.Objects;
+
+class T {
+    static class A {
+        static String a;
+    }
+    static boolean same(String s) {
+        return Objects.equals(A.a, s);
+    }
+}

plugins/InspectionGadgets/test/com/siyeh/igfixes/migration/equals_replaceable_by_objects_call/StaticField.java

@@ -0,0 +1,8 @@
+class T {
+    static class A {
+        static String a;
+    }
+    static boolean same(String s) {
+        return A.a != null && A.a.<caret>equals(s);
+    }
+}

plugins/InspectionGadgets/test/com/siyeh/igfixes/migration/equals_replaceable_by_objects_call/StaticField2.after.java

@@ -0,0 +1,10 @@
+import java.util.Objects;
+
+class T {
+    static class A {
+        static String a;
+    }
+    static boolean dfferent(String s) {
+        return !Objects.equals(A.a, s);
+    }
+}

plugins/InspectionGadgets/test/com/siyeh/igfixes/migration/equals_replaceable_by_objects_call/StaticField2.java

@@ -0,0 +1,8 @@
+class T {
+    static class A {
+        static String a;
+    }
+    static boolean dfferent(String s) {
+        return A.a != s && (A.a == null || !A.a.<caret>equals(s));
+    }
+}

plugins/InspectionGadgets/test/com/siyeh/igtest/migration/equals_replaceable_by_objects_call/EqualsReplaceableByObjectsCall.java

@@ -49,4 +49,23 @@ class EqualsReplaceableByObjectsCall {
       return <warning descr="'t != this && (t == null || !t.equals(this))' replaceable by 'Objects.equals()' expression">t != this && (t == null || !t.equals(this))</warning>;
     }
   }
+
+  static class A {
+    static String b;
+    static class B {
+      static String c;
+    }
+  }
+  static boolean ab1(String s) {
+    return <warning descr="'A.b.equals(s)' replaceable by 'Objects.equals()' expression">A.b.equals(s)</warning>;
+  }
+  static boolean ab2(String s) {
+    return <warning descr="'A.b != null && A.b.equals(s)' replaceable by 'Objects.equals()' expression">A.b != null && A.b.equals(s)</warning>;
+  }
+  static boolean ab3(String s) {
+    return <warning descr="'A.b == s || A.b != null && A.b.equals(s)' replaceable by 'Objects.equals()' expression">A.b == s || A.b != null && A.b.equals(s)</warning>;
+  }
+  static boolean abc(String s) {
+    return <warning descr="'A.B.c == s || A.B.c != null && A.B.c.equals(s)' replaceable by 'Objects.equals()' expression">A.B.c == s || A.B.c != null && A.B.c.equals(s)</warning>;
+  }
 }

plugins/InspectionGadgets/test/com/siyeh/igtest/migration/equals_replaceable_by_objects_call/EqualsReplaceableByObjectsCallCheckNull.java

@@ -49,4 +49,23 @@ class EqualsReplaceableByObjectsCall {
       return <warning descr="'t != this && (t == null || !t.equals(this))' replaceable by 'Objects.equals()' expression">t != this && (t == null || !t.equals(this))</warning>;
     }
   }
+
+  static class A {
+    static String b;
+    static class B {
+      static String c;
+    }
+  }
+  static boolean ab1(String s) {
+    return A.b.equals(s);
+  }
+  static boolean ab2(String s) {
+    return <warning descr="'A.b != null && A.b.equals(s)' replaceable by 'Objects.equals()' expression">A.b != null && A.b.equals(s)</warning>;
+  }
+  static boolean ab3(String s) {
+    return <warning descr="'A.b == s || A.b != null && A.b.equals(s)' replaceable by 'Objects.equals()' expression">A.b == s || A.b != null && A.b.equals(s)</warning>;
+  }
+  static boolean abc(String s) {
+    return <warning descr="'A.B.c == s || A.B.c != null && A.B.c.equals(s)' replaceable by 'Objects.equals()' expression">A.B.c == s || A.B.c != null && A.B.c.equals(s)</warning>;
+  }
 }

plugins/InspectionGadgets/testsrc/com/siyeh/ig/fixes/migration/EqualsReplaceableByObjectsCallFixTest.java

@@ -48,6 +48,9 @@ public class EqualsReplaceableByObjectsCallFixTest extends IGQuickFixesTestCase
   public void testQualifiedThisNotEqual() { doTest(); }
   public void testQualifiedSuperEqual() { doTest(); }
 
+  public void testStaticField() { doTest(); }
+  public void testStaticField2() { doTest(); }
+
   @Override
   protected void tuneFixture(JavaModuleFixtureBuilder builder) throws Exception {
     builder.addJdk(IdeaTestUtil.getMockJdk18Path().getPath())