From e129868d331e2f33897a4cb1288c4d151e25f5f5 Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Mon, 11 Sep 2017 17:43:19 +0300
Subject: [PATCH] unused: search for main in inner classes (IDEA-178721)

---
 .../deadCode/UnusedDeclarationInspectionBase.java  | 14 +++++++++++++-
 .../unusedDecls/InnerClassWithMainMethod.java      |  7 +++++++
 .../codeInsight/daemon/UnusedSymbolLocalTest.java  |  1 +
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 java/java-tests/testData/codeInsight/daemonCodeAnalyzer/unusedDecls/InnerClassWithMainMethod.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java b/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java
index f92423e6923c..ae334bfeefac 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java
@@ -400,7 +400,9 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
       if (isAddServletEnabled() && servlet != null && aClass.isInheritor(servlet, true)) {
         return true;
       }
-      if (isAddMainsEnabled() && PsiMethodUtil.hasMainMethod(aClass)) return true;
+      if (isAddMainsEnabled()) {
+        if (hasMainMethodDeep(aClass)) return true;
+      }
     }
     if (element instanceof PsiModifierListOwner) {
       final EntryPointsManager entryPointsManager = EntryPointsManager.getInstance(project);
@@ -414,6 +416,16 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
     return RefUtil.isImplicitUsage(element);
   }
 
+  private static boolean hasMainMethodDeep(PsiClass aClass) {
+    if (PsiMethodUtil.hasMainMethod(aClass)) return true;
+    for (PsiClass innerClass : aClass.getInnerClasses()) {
+      if (innerClass.hasModifierProperty(PsiModifier.STATIC) && PsiMethodUtil.hasMainMethod(innerClass)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   public boolean isGlobalEnabledInEditor() {
     return myEnabledInEditor;
   }
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/unusedDecls/InnerClassWithMainMethod.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/unusedDecls/InnerClassWithMainMethod.java
new file mode 100644
index 000000000000..0b8919a4754a
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/unusedDecls/InnerClassWithMainMethod.java
@@ -0,0 +1,7 @@
+class Test {
+    static class NestedTest {
+        public static void main(String[] args) {
+            new Test();
+        }
+    }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/UnusedSymbolLocalTest.java b/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/UnusedSymbolLocalTest.java
index 61c4ff17962a..b51d802a2c38 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/UnusedSymbolLocalTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/UnusedSymbolLocalTest.java
@@ -35,6 +35,7 @@ public class UnusedSymbolLocalTest extends DaemonAnalyzerTestCase {
   }
 
   public void testInnerClass() throws Exception { doTest(); }
+  public void testInnerClassWithMainMethod() throws Exception { doTest(); }
   public void testInnerUsesSelf() throws Exception { doTest(); }
   public void testLocalClass() throws Exception { doTest(); }
   public void testPrivateConstructor() throws Exception { doTest(); }