do not mark methods as always inverted when they are used as method references (IDEA-133555)

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/intellij/codeInspection/booleanIsAlwaysInverted/BooleanMethodIsAlwaysInvertedInspectionBase.java

@@ -77,6 +77,14 @@ public class BooleanMethodIsAlwaysInvertedInspectionBase extends GlobalJavaBatch
           refMethod.putUserData(ALWAYS_INVERTED, Boolean.FALSE);
         }
       }
+
+      @Override
+      public void visitMethodReferenceExpression(PsiMethodReferenceExpression expression) {
+        super.visitMethodReferenceExpression(expression);
+        if (expression.isReferenceTo(psiElement)) {
+          refMethod.putUserData(ALWAYS_INVERTED, Boolean.FALSE);
+        }
+      }
     });
   }
 

plugins/InspectionGadgets/test/invertedBoolean/methodReferenceIgnored/expected.xml

@@ -0,0 +1,3 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+</problems>

plugins/InspectionGadgets/test/invertedBoolean/methodReferenceIgnored/src/Test.java

@@ -0,0 +1,14 @@
+class Test {
+  {
+    I ii = this::isFoo;
+    if (!isFoo());
+  }
+
+  boolean isFoo() {
+    return true;
+  }
+
+  interface I {
+    boolean i();
+  }
+}

plugins/InspectionGadgets/testsrc/com/intellij/codeInspection/BooleanMethodInvertedTest.java

@@ -1,5 +1,8 @@
 package com.intellij.codeInspection;
 
+import com.intellij.codeInspection.ex.GlobalInspectionToolWrapper;
+import com.intellij.openapi.roots.LanguageLevelProjectExtension;
+import com.intellij.pom.java.LanguageLevel;
 import com.siyeh.ig.IGInspectionTestCase;
 import com.intellij.codeInspection.booleanIsAlwaysInverted.BooleanMethodIsAlwaysInvertedInspection;
 
@@ -61,6 +64,18 @@ public class BooleanMethodInvertedTest extends IGInspectionTestCase {
     doTest();
   }
 
+  public void testMethodReferenceIgnored() throws Exception {
+    final LanguageLevelProjectExtension projectExtension = LanguageLevelProjectExtension.getInstance(getJavaFacade().getProject());
+    final LanguageLevel oldLevel = projectExtension.getLanguageLevel();
+    try {
+      projectExtension.setLanguageLevel(LanguageLevel.JDK_1_8);
+      doTest();
+    }
+    finally {
+      projectExtension.setLanguageLevel(oldLevel);
+    }
+  }
+
   private void doTest() throws Exception {
     doTest(false);
   }