From 23256c9a59f26af1de6c15022ced330b8f4ada7e Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Mon, 11 Aug 2014 17:20:31 +0400
Subject: [PATCH] method reference: enable constructor refs completion
 (IDEA-124541)

---
 .../completion/JavaMethodCallElement.java         |  6 +++++-
 .../MethodReferenceCompletionProvider.java        | 15 +++++++--------
 .../src/com/intellij/psi/filters/FilterUtil.java  |  6 ++++++
 .../completion/smartType/ConstructorRef-out.java  | 14 ++++++++++++++
 .../completion/smartType/ConstructorRef.java      | 14 ++++++++++++++
 .../completion/SmartType18CompletionTest.java     |  4 ++++
 6 files changed, 50 insertions(+), 9 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef-out.java
 create mode 100644 java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef.java

diff --git a/java/java-impl/src/com/intellij/codeInsight/completion/JavaMethodCallElement.java b/java/java-impl/src/com/intellij/codeInsight/completion/JavaMethodCallElement.java
index 29906bbde605..c0f82668f74a 100644
--- a/java/java-impl/src/com/intellij/codeInsight/completion/JavaMethodCallElement.java
+++ b/java/java-impl/src/com/intellij/codeInsight/completion/JavaMethodCallElement.java
@@ -39,7 +39,11 @@ public class JavaMethodCallElement extends LookupItem<PsiMethod> implements Type
   private boolean myMayNeedExplicitTypeParameters;
 
   public JavaMethodCallElement(@NotNull PsiMethod method) {
-    super(method, method.getName());
+    this(method, method.getName());
+  }
+
+  public JavaMethodCallElement(@NotNull PsiMethod method, String methodName) {
+    super(method, methodName);
     myMethod = method;
     myHelper = null;
     myContainingClass = method.getContainingClass();
diff --git a/java/java-impl/src/com/intellij/codeInsight/completion/MethodReferenceCompletionProvider.java b/java/java-impl/src/com/intellij/codeInsight/completion/MethodReferenceCompletionProvider.java
index e83f0ef38c3c..494ed110b254 100644
--- a/java/java-impl/src/com/intellij/codeInsight/completion/MethodReferenceCompletionProvider.java
+++ b/java/java-impl/src/com/intellij/codeInsight/completion/MethodReferenceCompletionProvider.java
@@ -68,7 +68,7 @@ public class MethodReferenceCompletionProvider extends CompletionProvider<Comple
                   final PsiElement resolve = referenceExpression.resolve();
                   if (resolve != null && PsiEquivalenceUtil.areElementsEquivalent(element, resolve) && 
                       PsiMethodReferenceUtil.checkMethodReferenceContext(referenceExpression, resolve, functionalType) == null) {
-                    result.addElement(new JavaMethodReferenceElement((PsiMethod)element, refPlace, referenceExpression));
+                    result.addElement(new JavaMethodReferenceElement((PsiMethod)element, refPlace));
                   }
                 }
                 finally {
@@ -80,19 +80,20 @@ public class MethodReferenceCompletionProvider extends CompletionProvider<Comple
             }
 
             private PsiMethodReferenceExpression createMethodReferenceExpression(PsiMethod method) {
+              PsiElementFactory elementFactory = JavaPsiFacade.getElementFactory(method.getProject());
               if (refPlace instanceof PsiMethodReferenceExpression) {
                 final PsiMethodReferenceExpression referenceExpression = (PsiMethodReferenceExpression)refPlace.copy();
                 final PsiElement referenceNameElement = referenceExpression.getReferenceNameElement();
                 LOG.assertTrue(referenceNameElement != null, referenceExpression);
-                referenceNameElement.replace(JavaPsiFacade.getElementFactory(method.getProject()).createIdentifier(method.getName()));
+                referenceNameElement.replace(method.isConstructor() ? elementFactory.createKeyword("new") : elementFactory.createIdentifier(method.getName()));
                 return referenceExpression;
               }
               else if (method.hasModifierProperty(PsiModifier.STATIC)) {
                 final PsiClass aClass = method.getContainingClass();
                 LOG.assertTrue(aClass != null);
                 final String qualifiedName = aClass.getQualifiedName();
-                return (PsiMethodReferenceExpression)JavaPsiFacade.getElementFactory(method.getProject()).createExpressionFromText(
-                  qualifiedName + "::" + method.getName(), refPlace);
+                return (PsiMethodReferenceExpression)elementFactory.createExpressionFromText(
+                  qualifiedName + "::" + (method.isConstructor() ? "new" : method.getName()), refPlace);
               }
               else {
                 return null;
@@ -113,13 +114,11 @@ public class MethodReferenceCompletionProvider extends CompletionProvider<Comple
   private static class JavaMethodReferenceElement extends JavaMethodCallElement {
     private final PsiMethod myMethod;
     private final PsiElement myRefPlace;
-    private PsiMethodReferenceExpression myReferenceExpression;
 
-    public JavaMethodReferenceElement(PsiMethod method, PsiElement refPlace, PsiMethodReferenceExpression referenceExpression) {
-      super(method);
+    public JavaMethodReferenceElement(PsiMethod method, PsiElement refPlace) {
+      super(method, method.isConstructor() ? "new" : method.getName());
       myMethod = method;
       myRefPlace = refPlace;
-      myReferenceExpression = referenceExpression;
     }
 
     @Override
diff --git a/java/java-impl/src/com/intellij/psi/filters/FilterUtil.java b/java/java-impl/src/com/intellij/psi/filters/FilterUtil.java
index 89033fae439f..061e0bf18916 100644
--- a/java/java-impl/src/com/intellij/psi/filters/FilterUtil.java
+++ b/java/java-impl/src/com/intellij/psi/filters/FilterUtil.java
@@ -40,6 +40,12 @@ public class FilterUtil{
       return JavaPsiFacade.getInstance(element.getProject()).getElementFactory().createType((PsiClass)element);
     }
     if(element instanceof PsiMethod){
+      if (((PsiMethod)element).isConstructor()) {
+        final PsiClass containingClass = ((PsiMethod)element).getContainingClass();
+        if (containingClass != null) {
+          return JavaPsiFacade.getInstance(element.getProject()).getElementFactory().createType(containingClass);
+        }
+      }
       return ((PsiMethod)element).getReturnType();
     }
     if(element instanceof PsiVariable){
diff --git a/java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef-out.java b/java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef-out.java
new file mode 100644
index 000000000000..19decec183b0
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef-out.java
@@ -0,0 +1,14 @@
+@FunctionalInterface
+interface Foo9 {
+  Bar test(int p);
+}
+
+class Bar {
+  public Bar(int p) {}
+}
+
+class Test88 {
+  void foo(Foo9 foo) {
+    foo(Bar::new<caret>);
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef.java b/java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef.java
new file mode 100644
index 000000000000..7f7af003b377
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/smartType/ConstructorRef.java
@@ -0,0 +1,14 @@
+@FunctionalInterface
+interface Foo9 {
+  Bar test(int p);
+}
+
+class Bar {
+  public Bar(int p) {}
+}
+
+class Test88 {
+  void foo(Foo9 foo) {
+    foo(Bar::<caret>);
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartType18CompletionTest.java b/java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartType18CompletionTest.java
index 8aee494012cb..d98f0a68b72b 100644
--- a/java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartType18CompletionTest.java
+++ b/java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartType18CompletionTest.java
@@ -81,6 +81,10 @@ public class SmartType18CompletionTest extends LightFixtureCompletionTestCase {
     doTest();
   }
 
+  public void testConstructorRef() throws Exception {
+    doTest(false);
+  }
+
   public void testFilteredMethodReference() throws Exception {
     doTest(false);
   }