delegate methods: restore ellipsis type (IDEA-171529)

java/java-impl/src/com/intellij/codeInsight/generation/GenerateMembersUtil.java

@@ -451,7 +451,11 @@ public class GenerateMembersUtil {
         paramName = generator.generateUniqueName(paramName);
       }
       generator.addExistingName(paramName);
-      result[i] = factory.createParameter(paramName, GenericsUtil.getVariableTypeByExpressionType(substituted), target);
+      PsiType expressionType = GenericsUtil.getVariableTypeByExpressionType(substituted);
+      if (expressionType instanceof PsiArrayType && substituted instanceof PsiEllipsisType) {
+        expressionType = new PsiEllipsisType(((PsiArrayType)expressionType).getComponentType());
+      }
+      result[i] = factory.createParameter(paramName, expressionType, target);
     }
     return result;
   }

java/java-tests/testData/codeInsight/delegateMethods/afterPreserveEllipsisType.java

@@ -0,0 +1,11 @@
+class Foo {
+    void foo(String... s) {}
+}
+
+class Bar {
+    Foo myDelegate;
+
+    public void foo(String... s) {
+        myDelegate.foo(s);
+    }
+}

java/java-tests/testData/codeInsight/delegateMethods/beforePreserveEllipsisType.java

@@ -0,0 +1,8 @@
+class Foo {
+    void foo(String... s) {}
+}
+
+class Bar {
+    Foo myDelegate;
+    <caret>
+}

java/java-tests/testSrc/com/intellij/codeInsight/DelegateMethodsTest.java

@@ -100,6 +100,10 @@ public class DelegateMethodsTest extends LightCodeInsightTestCase {
     doTest();
   }
 
+  public void testPreserveEllipsisType() throws Exception {
+    doTest();
+  }
+
   private void doTest() throws Exception {
     doTest(getTestName(false));
   }