enable common dataflow for class initializers

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/CommonDataflow.java

@@ -88,9 +88,10 @@ public class CommonDataflow {
 
   private static DataflowResult getDataflowResult(PsiElement context) {
     PsiMember member = PsiTreeUtil.getParentOfType(context, PsiMember.class);
-    if(!(member instanceof PsiMethod)) return null;
+    if(!(member instanceof PsiMethod) && !(member instanceof PsiClassInitializer)) return null;
     return CachedValuesManager.getCachedValue(member, () -> {
-      PsiCodeBlock body = ((PsiMethod)member).getBody();
+      PsiCodeBlock body = member instanceof PsiMethod ? ((PsiMethod)member).getBody() 
+                                                      : ((PsiClassInitializer)member).getBody();
       DataflowResult result = runDFA(body);
       return CachedValueProvider.Result.create(result, PsiModificationTracker.MODIFICATION_COUNT);
     });

plugins/InspectionGadgets/test/com/siyeh/igtest/controlflow/simplifiable_equals_expression/SimplifiableEqualsExpression.java

@@ -50,6 +50,16 @@ public class SimplifiableEqualsExpression {
       System.out.println("...");
     }
   }
+  
+  private static final boolean DEBUG = false;
+  
+  {
+    String s1 = DEBUG ? "null" : null;
+    
+    if(<warning descr="Unnecessary 'null' check before 'equals()' call">s1 == null</warning> || !s1.equals("")) {
+      System.out.println("...");
+    }
+  }
 
   void test(List<String> list) {
     String s = list.get(0);