From 6ac6e6712b3cd8c7e72162a6c91a60dc59d55094 Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Wed, 3 Aug 2016 15:24:48 +0200
Subject: [PATCH] IDEA-157088 The autocomplete to offer not only the
 implementation of the interface, but the interface itself

---
 .../codeInsight/completion/JavaInheritorsGetter.java       | 7 ++++++-
 .../normal/SuggestInterfaceArrayWhenObjectIsExpected.java  | 5 +++++
 .../codeInsight/completion/NormalCompletionTest.groovy     | 6 ++++++
 3 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 java/java-tests/testData/codeInsight/completion/normal/SuggestInterfaceArrayWhenObjectIsExpected.java

diff --git a/java/java-impl/src/com/intellij/codeInsight/completion/JavaInheritorsGetter.java b/java/java-impl/src/com/intellij/codeInsight/completion/JavaInheritorsGetter.java
index 038b722f83f3..a935b1c66eba 100644
--- a/java/java-impl/src/com/intellij/codeInsight/completion/JavaInheritorsGetter.java
+++ b/java/java-impl/src/com/intellij/codeInsight/completion/JavaInheritorsGetter.java
@@ -83,11 +83,16 @@ public class JavaInheritorsGetter extends CompletionProvider<CompletionParameter
 
     addArrayTypes(parameters.getPosition(), infos, consumer);
 
-    processInheritors(parameters, extractClassTypes(infos), prefixMatcher, type -> {
+    List<PsiClassType> classTypes = extractClassTypes(infos);
+    boolean arraysWelcome = classTypes.stream().anyMatch(t -> t.equalsToText(CommonClassNames.JAVA_LANG_OBJECT));
+    processInheritors(parameters, classTypes, prefixMatcher, type -> {
       final LookupElement element = addExpectedType(type, parameters);
       if (element != null) {
         consumer.consume(element);
       }
+      if (arraysWelcome) {
+        consumer.consume(createNewArrayItem(parameters.getPosition(), type.createArrayType()));
+      }
     });
   }
 
diff --git a/java/java-tests/testData/codeInsight/completion/normal/SuggestInterfaceArrayWhenObjectIsExpected.java b/java/java-tests/testData/codeInsight/completion/normal/SuggestInterfaceArrayWhenObjectIsExpected.java
new file mode 100644
index 000000000000..9a449e918869
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/normal/SuggestInterfaceArrayWhenObjectIsExpected.java
@@ -0,0 +1,5 @@
+interface MyIntf {}
+
+class C {
+    Object[] o = {new MyInt<caret>};
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/codeInsight/completion/NormalCompletionTest.groovy b/java/java-tests/testSrc/com/intellij/codeInsight/completion/NormalCompletionTest.groovy
index fed893a48af9..ac7bf94e039e 100644
--- a/java/java-tests/testSrc/com/intellij/codeInsight/completion/NormalCompletionTest.groovy
+++ b/java/java-tests/testSrc/com/intellij/codeInsight/completion/NormalCompletionTest.groovy
@@ -1597,4 +1597,10 @@ class Bar {
     assert !LookupElementPresentation.renderElement(myFixture.lookup.items[2]).tailText
     assert LookupElementPresentation.renderElement(myFixture.lookup.items[3]).tailText == ' = 42'
   }
+
+  public void testSuggestInterfaceArrayWhenObjectIsExpected() {
+    configure()
+    assert LookupElementPresentation.renderElement(myFixture.lookup.items[0]).tailText.contains('{...}')
+    assert LookupElementPresentation.renderElement(myFixture.lookup.items[1]).tailText.contains('[]')
+  }
 }