Introduce Variable: Parenthesize binary expressions if operation references starts with a new line

#KT-3933 Fixed

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceVariable/KotlinIntroduceVariableHandler.kt

@@ -132,6 +132,13 @@ object KotlinIntroduceVariableHandler : KotlinIntroduceHandlerBase() {
             return result
         }
 
+        private fun KtExpression.mustBeParenthesizedInInitializerPosition(): Boolean {
+            if (this !is KtBinaryExpression) return false
+
+            if (left?.mustBeParenthesizedInInitializerPosition() ?: false) return true
+            return PsiChildRange(left, operationReference).any { (it is PsiWhiteSpace) && it.textContains('\n') }
+        }
+
         private fun runRefactoring (
                 expression: KtExpression,
                 commonContainer: PsiElement,
@@ -139,11 +146,13 @@ object KotlinIntroduceVariableHandler : KotlinIntroduceHandlerBase() {
                 allReplaces: List<KtExpression>
         ) {
             val initializer = (expression as? KtParenthesizedExpression)?.expression ?: expression
+            val initializerText = if (initializer.mustBeParenthesizedInInitializerPosition()) "(${initializer.text})" else initializer.text
+
             var property: KtDeclaration = if (componentFunctions.isNotEmpty()) {
                 buildString {
                     componentFunctions.indices.joinTo(this, prefix = "val (", postfix = ")") { nameSuggestions[it].first() }
                     append(" = ")
-                    append(initializer.text)
+                    append(initializerText)
                 }.let { psiFactory.createDestructuringDeclaration(it) }
             }
             else {
@@ -155,7 +164,7 @@ object KotlinIntroduceVariableHandler : KotlinIntroduceHandlerBase() {
                         append(": ").append(IdeDescriptorRenderers.SOURCE_CODE.renderType(typeToRender))
                     }
                     append(" = ")
-                    append(initializer.text)
+                    append(initializerText)
                 }.let { psiFactory.createProperty(it) }
             }
 

idea/testData/refactoring/introduceVariable/multilineBinaryExpression.kt

@@ -0,0 +1,6 @@
+fun foo(i: Int) { }
+
+fun test() {
+    foo(<selection>1
+        + 2</selection>)
+}

idea/testData/refactoring/introduceVariable/multilineBinaryExpression.kt.after

@@ -0,0 +1,7 @@
+fun foo(i: Int) { }
+
+fun test() {
+    val i = (1
+            + 2)
+    foo(i)
+}

idea/testData/refactoring/introduceVariable/multilineBinaryExpressionWithComments.kt

@@ -0,0 +1,6 @@
+fun foo(i: Int) { }
+
+fun test() {
+    foo(<selection>1 // abc
+        /*def*/ + 2</selection>)
+}

idea/testData/refactoring/introduceVariable/multilineBinaryExpressionWithComments.kt.after

@@ -0,0 +1,7 @@
+fun foo(i: Int) { }
+
+fun test() {
+    val i = (1 // abc
+            /*def*/ + 2)
+    foo(i)
+}

idea/testData/refactoring/introduceVariable/multilineNestedBinaryExpression1.kt

@@ -0,0 +1,6 @@
+fun foo(i: Int) { }
+
+fun test() {
+    foo(<selection>1
+        + 2 - 3</selection>)
+}

idea/testData/refactoring/introduceVariable/multilineNestedBinaryExpression1.kt.after

@@ -0,0 +1,7 @@
+fun foo(i: Int) { }
+
+fun test() {
+    val i = (1
+            + 2 - 3)
+    foo(i)
+}

idea/testData/refactoring/introduceVariable/multilineNestedBinaryExpression2.kt

@@ -0,0 +1,6 @@
+fun foo(i: Int) { }
+
+fun test() {
+    foo(<selection>1 + 2
+        - 3</selection>)
+}

idea/testData/refactoring/introduceVariable/multilineNestedBinaryExpression2.kt.after

@@ -0,0 +1,7 @@
+fun foo(i: Int) { }
+
+fun test() {
+    val i = (1 + 2
+            - 3)
+    foo(i)
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/ExtractionTestGenerated.java

@@ -235,6 +235,30 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
             doIntroduceVariableTest(fileName);
         }
 
+        @TestMetadata("multilineBinaryExpression.kt")
+        public void testMultilineBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/multilineBinaryExpression.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
+        @TestMetadata("multilineBinaryExpressionWithComments.kt")
+        public void testMultilineBinaryExpressionWithComments() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/multilineBinaryExpressionWithComments.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
+        @TestMetadata("multilineNestedBinaryExpression1.kt")
+        public void testMultilineNestedBinaryExpression1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/multilineNestedBinaryExpression1.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
+        @TestMetadata("multilineNestedBinaryExpression2.kt")
+        public void testMultilineNestedBinaryExpression2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/multilineNestedBinaryExpression2.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
         @TestMetadata("NameSuggestionBug1.kt")
         public void testNameSuggestionBug1() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/NameSuggestionBug1.kt");