Extract Function: Merge initialized declarations on call site when possible

idea/src/org/jetbrains/jet/plugin/refactoring/extractFunction/extractorUtil.kt

@@ -52,6 +52,7 @@ import org.jetbrains.jet.lang.psi.JetReturnExpression
 import org.jetbrains.jet.plugin.refactoring.JetNameValidatorImpl
 import org.jetbrains.jet.plugin.refactoring.JetNameSuggester
 import org.jetbrains.jet.plugin.refactoring.isMultiLine
+import org.jetbrains.jet.plugin.refactoring.extractFunction.OutputValueBoxer.AsTuple
 
 fun ExtractableCodeDescriptor.getDeclarationText(
         options: ExtractionGeneratorOptions = ExtractionGeneratorOptions.DEFAULT,
@@ -311,6 +312,24 @@ fun ExtractableCodeDescriptor.generateDeclaration(options: ExtractionGeneratorOp
 
         val newLine = psiFactory.createNewLine()
 
+        if (controlFlow.outputValueBoxer is AsTuple && controlFlow.outputValues.size > 1 && controlFlow.outputValues.all { it is Initializer }) {
+            val declarationsToMerge = controlFlow.outputValues.map { (it as Initializer).initializedDeclaration }
+            val isVar = declarationsToMerge.first().isVar()
+            if (declarationsToMerge.all { it.isVar() == isVar }) {
+                controlFlow.declarationsToCopy.subtract(declarationsToMerge).forEach {
+                    block.addBefore(psiFactory.createDeclaration<JetDeclaration>(it.getText()!!), anchorInBlock) as JetDeclaration
+                    block.addBefore(newLine, anchorInBlock)
+                }
+
+                val entries = declarationsToMerge.map { p -> p.getName() + (p.getTypeRef()?.let { ": ${it.getText()}" } ?: "") }
+                anchorInBlock?.replace(
+                        psiFactory.createDeclaration("${if (isVar) "var" else "val"} (${entries.joinToString()}) = $callText")
+                )
+
+                return
+            }
+        }
+
         val inlinableCall = controlFlow.outputValues.size <= 1
         val unboxingExpressions =
                 if (inlinableCall) {

idea/testData/refactoring/extractFunction/controlFlow/outputValues/pairOfInitalizersWithNonLocalUsages.kt.after

@@ -1,9 +1,7 @@
 // WITH_RUNTIME
 // SIBLING:
 fun foo() {
-    val pair = pair()
+    val (a, b) = pair()
-    val a = pair.first
-    val b = pair.second
     println(a + b)
 }
 

idea/testData/refactoring/extractFunction/controlFlow/outputValues/pairOfVarInitalizersWithNonLocalUsages.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+// SIBLING:
+fun foo() {
+    <selection>var a = 1
+    var b = 2</selection>
+    println(a + b)
+}

idea/testData/refactoring/extractFunction/controlFlow/outputValues/pairOfVarInitalizersWithNonLocalUsages.kt.after

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+// SIBLING:
+fun foo() {
+    var (a, b) = pair()
+    println(a + b)
+}
+
+private fun pair(): Pair<Int, Int> {
+    var a = 1
+    var b = 2
+    return Pair(a, b)
+}

idea/testData/refactoring/extractFunction/controlFlow/outputValues/valAndVarInitalizersWithNonLocalUsages.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+// SIBLING:
+fun foo() {
+    <selection>val a = 1
+    var b = 2</selection>
+    println(a + b)
+}

idea/testData/refactoring/extractFunction/controlFlow/outputValues/valAndVarInitalizersWithNonLocalUsages.kt.after

@@ -0,0 +1,14 @@
+// WITH_RUNTIME
+// SIBLING:
+fun foo() {
+    val pair = pair()
+    val a = pair.first
+    var b = pair.second
+    println(a + b)
+}
+
+private fun pair(): Pair<Int, Int> {
+    val a = 1
+    var b = 2
+    return Pair(a, b)
+}

idea/tests/org/jetbrains/jet/plugin/refactoring/introduce/introduceVariable/JetExtractionTestGenerated.java

@@ -769,6 +769,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                     doExtractFunctionTest(fileName);
                 }
                 
+                @TestMetadata("pairOfVarInitalizersWithNonLocalUsages.kt")
+                public void testPairOfVarInitalizersWithNonLocalUsages() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/controlFlow/outputValues/pairOfVarInitalizersWithNonLocalUsages.kt");
+                    doExtractFunctionTest(fileName);
+                }
+                
                 @TestMetadata("pairWithIf.kt")
                 public void testPairWithIf() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/controlFlow/outputValues/pairWithIf.kt");
@@ -841,6 +847,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                     doExtractFunctionTest(fileName);
                 }
                 
+                @TestMetadata("valAndVarInitalizersWithNonLocalUsages.kt")
+                public void testValAndVarInitalizersWithNonLocalUsages() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/controlFlow/outputValues/valAndVarInitalizersWithNonLocalUsages.kt");
+                    doExtractFunctionTest(fileName);
+                }
+                
                 @TestMetadata("valuesUsedInLambdaOnly.kt")
                 public void testValuesUsedInLambdaOnly() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/controlFlow/outputValues/valuesUsedInLambdaOnly.kt");