ConstantExpressionInspection: make it working inside parentheses

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/constantExpression/afterParens.java

@@ -0,0 +1,4 @@
+// "Replace '"a" + "b"' with constant value '"ab"'" "true"
+class Test {
+  String x = ("ab");
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/constantExpression/beforeParens.java

@@ -0,0 +1,4 @@
+// "Replace '"a" + "b"' with constant value '"ab"'" "true"
+class Test {
+  String x = ("a" + <caret>"b");
+}

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/style/ConstantExpressionInspection.java

@@ -43,7 +43,7 @@ public class ConstantExpressionInspection extends AbstractBaseJavaLocalInspectio
         if (expression.getTextLength() > MAX_EXPRESSION_LENGTH) return;
         if (expression.getType() == null) return;
         if (!PsiUtil.isConstantExpression(expression)) return;
-        final PsiElement parent = expression.getParent();
+        final PsiElement parent = PsiUtil.skipParenthesizedExprUp(expression.getParent());
         if (parent instanceof PsiExpression && PsiUtil.isConstantExpression((PsiExpression)parent)) return;
         try {
           final Object value = ExpressionUtils.computeConstantExpression(expression, true);