Replace 'if' with 'when': don't remove branch brances

#KT-32650 Fixed

idea/src/org/jetbrains/kotlin/idea/intentions/branchedTransformations/intentions/IfToWhenIntention.kt

@@ -115,9 +115,9 @@ class IfToWhenIntention : SelfTargetingRangeIntention<KtIfExpression>(KtIfExpres
         }
     }
 
-    private fun BuilderByPattern<*>.appendElseBlock(block: KtExpression?) {
+    private fun BuilderByPattern<*>.appendElseBlock(block: KtExpression?, unwrapBlockOrParenthesis: Boolean = false) {
         appendFixedText("else->")
-        appendExpression(block?.unwrapBlockOrParenthesis())
+        appendExpression(if (unwrapBlockOrParenthesis) block?.unwrapBlockOrParenthesis() else block)
         appendFixedText("\n")
     }
 
@@ -160,7 +160,7 @@ class IfToWhenIntention : SelfTargetingRangeIntention<KtIfExpression>(KtIfExpres
                 appendFixedText("->")
 
                 val currentThenBranch = currentIfExpression.then
-                appendExpression(currentThenBranch?.unwrapBlockOrParenthesis())
+                appendExpression(currentThenBranch)
                 appendFixedText("\n")
 
                 canPassThrough = canPassThrough || canPassThrough(currentThenBranch)
@@ -175,7 +175,7 @@ class IfToWhenIntention : SelfTargetingRangeIntention<KtIfExpression>(KtIfExpres
                         currentIfExpression = syntheticElseBranch
                         toDelete.add(syntheticElseBranch)
                     } else {
-                        appendElseBlock(syntheticElseBranch)
+                        appendElseBlock(syntheticElseBranch, unwrapBlockOrParenthesis = true)
                         break
                     }
                 } else if (currentElseBranch is KtIfExpression) {

idea/testData/inspectionsLocal/cascadeIf/insideOtherIf.kt.after

@@ -3,9 +3,15 @@ fun println(s: String) {}
 fun test(x: Double, a: Boolean, b: Boolean) {
     if (x > 0.0) {
         when {
-            a -> println("a")
-            b -> println("b")
-            else -> println("none")
+            a -> {
+                println("a")
+            }
+            b -> {
+                println("b")
+            }
+            else -> {
+                println("none")
+            }
         }
     }
 }

idea/testData/inspectionsLocal/cascadeIf/normal.kt

@@ -2,12 +2,10 @@ fun println(s: String) {}
 
 fun test(a: Boolean, b: Boolean) {
     <caret>if (a) {
+        // comment
+        // comment
         println("a")
     }
-    else if (b) {
-        println("b")
-    }
-    else {
-        println("none")
-    }
+    else if (b) println("b")
+    else println("none")
 }

idea/testData/inspectionsLocal/cascadeIf/normal.kt.after

@@ -2,7 +2,11 @@ fun println(s: String) {}
 
 fun test(a: Boolean, b: Boolean) {
     when {
-        a -> println("a")
+        a -> {
+            // comment
+            // comment
+            println("a")
+        }
         b -> println("b")
         else -> println("none")
     }

idea/testData/inspectionsLocal/cascadeIf/withAnnotation.kt.after

@@ -1,9 +1,15 @@
 // WITH_RUNTIME
 fun foo(a: Any) {
     when (a) {
-        "" -> println(a)
-        is String -> println(a)
-        is List<*> -> @Suppress("UNCHECKED_CAST")
-        println(a as List<String>)
+        "" -> {
+            println(a)
+        }
+        is String -> {
+            println(a)
+        }
+        is List<*> -> {
+            @Suppress("UNCHECKED_CAST")
+            println(a as List<String>)
+        }
     }
 }

idea/testData/intentions/branched/ifWhen/ifToWhen/ifElseSwallowTail.kt.after

@@ -1,7 +1,11 @@
 fun toInt(s: Number): Int {
     when (s) {
-        is Int -> foo()
-        else -> return -1
+        is Int -> {
+            foo()
+        }
+        else -> {
+            return -1
+        }
     }
 
     // code below will be lost!

idea/testData/intentions/branched/ifWhen/ifToWhen/multipleIfFake.kt.after

@@ -1,6 +1,8 @@
 fun bar(arg: Int): Int {
     when {
-        arg < 0 -> if (arg == -3) return 0
+        arg < 0 -> {
+            if (arg == -3) return 0
+        }
     }
     if (arg > 0) {
         return 1

idea/testData/intentions/branched/ifWhen/ifToWhen/multipleIfWithReturns.kt.after

@@ -1,12 +1,18 @@
 fun foo(arg: Any?): Int {
     // 1
     when (arg) {
-        is Int -> return arg // 2
+        is Int -> {
+            return arg // 2
+        }
 // 3
-        is String -> return 42 // 4
+        is String -> {
+            return 42 // 4
+        }
 // 5
-        null -> // 6
+        null -> {
+            // 6
             return 0
+        }
 // 7
 // 8
         else -> return -1

idea/testData/intentions/branched/ifWhen/ifToWhen/onElseIf2.kt.after

@@ -1,8 +1,16 @@
 fun test(n: Int): String {
     return <caret>when (n) {
-        0 -> "zero"
-        1 -> "one"
-        2 -> "two"
-        else -> "unknown"
+        0 -> {
+            "zero"
+        }
+        1 -> {
+            "one"
+        }
+        2 -> {
+            "two"
+        }
+        else -> {
+            "unknown"
+        }
     }
 }

idea/testData/intentions/branched/ifWhen/ifToWhen/withAnnotation.kt.after

@@ -8,7 +8,11 @@ fun println(s: String) {}
 
 fun foo() {
     when {
-        @Ann b -> println("!")
-        else -> println("")
+        @Ann b -> {
+            println("!")
+        }
+        else -> {
+            println("")
+        }
     }
 }

idea/testData/intentions/branched/ifWhen/ifToWhen/withInternalLoop.kt.after

@@ -3,11 +3,17 @@
 fun testIf(xs: List<Any>) {
     loop@ for (x in xs) {
         when (x) {
-            is String -> for (c in x) {
-                continue // do not change
+            is String -> {
+                for (c in x) {
+                    continue // do not change
+                }
+            }
+            is Int -> {
+                break@loop
+            }
+            else -> {
+                println(x)
             }
-            is Int -> break@loop
-            else -> println(x)
         }
     }
 }

idea/testData/intentions/branched/ifWhen/ifToWhen/withInternalLoopOnly.kt.after

@@ -9,6 +9,8 @@ fun testIf(x: Any) {
                     break // do not change
             }
         }
-        else -> println(x)
+        else -> {
+            println(x)
+        }
     }
 }

idea/testData/intentions/branched/ifWhen/ifToWhen/withLoopDeep.kt.after

@@ -2,18 +2,22 @@ fun test() {
     loop@ while (true) {
         loop1@ for (i in -10..10) {
             when {
-                i < 0 -> if (i < -5) {
-                    break@loop1
-                } else {
-                    continue@loop
+                i < 0 -> {
+                    if (i < -5) {
+                        break@loop1
+                    } else {
+                        continue@loop
+                    }
                 }
-                else -> if (i == 0) {
-                    i.hashCode()
-                    break@loop1
-                } else if (i > 5) {
-                    i.hashCode()
-                } else {
-                    continue@loop1
+                else -> {
+                    if (i == 0) {
+                        i.hashCode()
+                        break@loop1
+                    } else if (i > 5) {
+                        i.hashCode()
+                    } else {
+                        continue@loop1
+                    }
                 }
             }
         }

idea/testData/intentions/branched/ifWhen/ifToWhen/withLoopDeepAndComments.kt.after

@@ -20,10 +20,14 @@ fun test() {
                         // Comment 7
                         break@loop1
                     }
-                    i > 5 -> // Comment 8
+                    i > 5 -> {
+                        // Comment 8
                         i.hashCode()
-                    else -> // Comment 9
+                    }
+                    else -> {
+                        // Comment 9
                         continue@loop1
+                    }
                 }
             }
         }

idea/testData/intentions/branched/ifWhen/ifToWhen/withLoopThen.kt.after

@@ -3,10 +3,14 @@ fun test() {
     loop@ for (i in -2..2) {
         // Some comment
         when {
-            i < 0 -> // Very important comment
+            i < 0 -> {
+                // Very important comment
                 break@loop
-            else -> // More comments
+            }
+            else -> {
+                // More comments
                 i.hashCode()
+            }
         }
     }
 }