From 4509cd43cbb501bc91afc3c910171a7a3efbbf74 Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <Mikhail.Glukhikh@jetbrains.com>
Date: Mon, 19 Sep 2016 10:58:37 +0300
Subject: [PATCH] Convert to expression body fix: do not allow `= Unit` for
 constructors

---
 .../idea/intentions/ConvertToExpressionBodyIntention.kt   | 8 +++++---
 .../convertToExpressionBody/constructorWithEmptyBody.kt   | 5 +++++
 .../kotlin/idea/intentions/IntentionTestGenerated.java    | 6 ++++++
 3 files changed, 16 insertions(+), 3 deletions(-)
 create mode 100644 idea/testData/intentions/convertToExpressionBody/constructorWithEmptyBody.kt

diff --git a/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertToExpressionBodyIntention.kt b/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertToExpressionBodyIntention.kt
index edc73396db4..eb433dda738 100644
--- a/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertToExpressionBodyIntention.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/intentions/ConvertToExpressionBodyIntention.kt
@@ -98,12 +98,14 @@ class ConvertToExpressionBodyIntention : SelfTargetingOffsetIndependentIntention
 
     private fun calcValue(declaration: KtDeclarationWithBody): KtExpression? {
         val body = declaration.blockExpression() ?: return null
-        return calcValue(body)
+        return calcValue(body, emptyAllowed = declaration !is KtConstructor<*>)
     }
 
-    private fun calcValue(body: KtBlockExpression): KtExpression? {
+    private fun calcValue(body: KtBlockExpression, emptyAllowed: Boolean = true): KtExpression? {
         val bodyStatements = body.statements
-        if (bodyStatements.isEmpty()) return KtPsiFactory(body).createExpression("Unit")
+        if (bodyStatements.isEmpty()) {
+            return if (emptyAllowed) KtPsiFactory(body).createExpression("Unit") else null
+        }
         val statement = bodyStatements.singleOrNull() ?: return null
         when (statement) {
             is KtReturnExpression -> {
diff --git a/idea/testData/intentions/convertToExpressionBody/constructorWithEmptyBody.kt b/idea/testData/intentions/convertToExpressionBody/constructorWithEmptyBody.kt
new file mode 100644
index 00000000000..590744d01a1
--- /dev/null
+++ b/idea/testData/intentions/convertToExpressionBody/constructorWithEmptyBody.kt
@@ -0,0 +1,5 @@
+// IS_APPLICABLE: false
+
+class C {
+    constructor()<caret> {}
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
index 3bafcd4fc93..24d11735a68 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
@@ -4903,6 +4903,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("constructorWithEmptyBody.kt")
+        public void testConstructorWithEmptyBody() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/constructorWithEmptyBody.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("declaration.kt")
         public void testDeclaration() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/declaration.kt");