unguarded field access: support sync expressions (IDEA-153399)

java/java-analysis-impl/src/com/intellij/codeInspection/concurrencyAnnotations/FieldAccessNotGuardedInspection.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.codeInspection.concurrencyAnnotations;
 
+import com.intellij.codeInsight.PsiEquivalenceUtil;
 import com.intellij.codeInsight.daemon.GroupNames;
 import com.intellij.codeInspection.BaseJavaBatchLocalInspectionTool;
 import com.intellij.codeInspection.ProblemsHolder;
@@ -81,6 +82,20 @@ public class FieldAccessNotGuardedInspection extends BaseJavaBatchLocalInspectio
         if (containingMethod != null && containingMethod.hasModifierProperty(PsiModifier.SYNCHRONIZED)) {
           return;
         }
+
+        final PsiSynchronizedStatement synchronizedStatement = PsiTreeUtil.getParentOfType(expression, PsiSynchronizedStatement.class);
+        if (synchronizedStatement != null) {
+          final PsiExpression lockExpression = synchronizedStatement.getLockExpression();
+          final PsiExpression qualifierExpression = expression.getQualifierExpression();
+          if (lockExpression instanceof PsiThisExpression && qualifierExpression == null) {
+            return;
+          }
+          if (lockExpression instanceof PsiReferenceExpression &&
+              qualifierExpression != null &&
+              PsiEquivalenceUtil.areElementsEquivalent(lockExpression, qualifierExpression)) {
+            return;
+          }
+        }
       }
 
       if (findLockTryStatement(expression, guard) != null) {

java/java-tests/testData/inspection/guarded/syncOnFieldQualifier.java

@@ -0,0 +1,21 @@
+import javax.annotation.concurrent.GuardedBy;
+
+class Example
+{
+    private final Distribution distribution = new Distribution();
+
+    public void add(long value)
+    {
+        synchronized (distribution) {
+            distribution.total += value;
+            <error descr="Cannot resolve symbol 'total'">total</error> += value;
+        }
+
+    }
+
+    protected static class Distribution
+    {
+        @GuardedBy("this")
+        private long total = 0;
+    }
+}

java/java-tests/testSrc/com/intellij/codeInspection/FieldAccessedNotGuardedInspectionTest.java

@@ -24,11 +24,20 @@ import org.jetbrains.annotations.NotNull;
 public class FieldAccessedNotGuardedInspectionTest extends LightCodeInsightFixtureTestCase {
   public void testItself() throws Exception {
     myFixture.addClass("package net.jcip.annotations;\n" + getGuardedByAnnotationText());
-    myFixture.testHighlighting(true, false, false, getTestName(true) + ".java");
+    doTest();
   }
 
   public void testJavax_itself() throws Exception {
     myFixture.addClass("package javax.annotation.concurrent;\n" + getGuardedByAnnotationText());
+    doTest();
+  }
+
+  public void testSyncOnFieldQualifier() throws Exception {
+    myFixture.addClass("package javax.annotation.concurrent;\n" + getGuardedByAnnotationText());
+    doTest();
+  }
+
+  private void doTest() {
     myFixture.testHighlighting(true, false, false, getTestName(true) + ".java");
   }