"Invert if condition" intention works better for non-symmetric if's

#KT-5009 Fixed

idea/testData/intentions/invertIfCondition/functionWithReturnExpression.kt.after

@@ -1,10 +1,8 @@
 fun foo(): Int {
     val x = 0
 
-    if (x != 1) {
-    } else {
-        x + 1
-    }
+    if (x != 1) return x
+    x + 1
 
     return x
 }

idea/testData/intentions/invertIfCondition/ifExpressionInsideForLoop.kt.after

@@ -3,9 +3,7 @@ fun main() {
     val list = 1..4
 
     for (x in list) {
-        if (x != 2) {
-        } else {
-            list
-        }
+        if (x != 2) continue
+        list
     }
 }

idea/testData/intentions/invertIfCondition/ifExpressionWithReturn.kt.after

@@ -2,7 +2,7 @@ fun foo(): Int {
     val x = 0
 
     if (x != 1) {
-    } else return x + 1
-
-    return 0
+        return 0
+    }
+    return x + 1
 }

idea/testData/intentions/invertIfCondition/ifThenReturn.kt

@@ -0,0 +1,13 @@
+fun foo(): Boolean {
+    val x = 2
+    <caret>if (x <= 1) {
+        bar1()
+        bar2()
+        return false
+    }
+    bar1()
+    return true
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/ifThenReturn.kt.after

@@ -0,0 +1,13 @@
+fun foo(): Boolean {
+    val x = 2
+    <caret>if (x > 1) {
+        bar1()
+        return true
+    }
+    bar1()
+    bar2()
+    return false
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/ifThenReturn2.kt

@@ -0,0 +1,12 @@
+fun foo() {
+    val x = 2
+    <caret>if (x <= 1) {
+        bar1()
+        bar2()
+        return
+    }
+    bar1()
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/ifThenReturn2.kt.after

@@ -0,0 +1,12 @@
+fun foo() {
+    val x = 2
+    <caret>if (x > 1) {
+        bar1()
+        return
+    }
+    bar1()
+    bar2()
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/ifThenReturn3.kt

@@ -0,0 +1,7 @@
+fun foo() {
+    val x = 2
+    <caret>if (x <= 1) return
+    bar()
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/ifThenReturn3.kt.after

@@ -0,0 +1,8 @@
+fun foo() {
+    val x = 2
+    <caret>if (x > 1) {
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/ifThenReturn4.kt

@@ -0,0 +1,14 @@
+fun foo(p: Int): Int {
+    if (p > 0) {
+        val x = p / 2
+        <caret>if (x <= 1) return 1
+        bar1()
+    }
+    else {
+        bar2()
+    }
+    return 2
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/ifThenReturn4.kt.after

@@ -0,0 +1,17 @@
+fun foo(p: Int): Int {
+    if (p > 0) {
+        val x = p / 2
+        if (x > 1) {
+            bar1()
+            return 2
+        }
+        return 1
+    }
+    else {
+        bar2()
+    }
+    return 2
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/invertableOperator.kt.after

@@ -1,4 +1,3 @@
 fun main() {
-    if (true != false) {
-    }
+    if (true != false) return
 }

idea/testData/intentions/invertIfCondition/lastStatement1.kt

@@ -0,0 +1,12 @@
+fun foo() {
+    val x = 2
+    <caret>if (x > 1) {
+        // invoke bar1&bar2
+        bar1()
+        bar2()
+        // done
+    }
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/lastStatement1.kt.after

@@ -0,0 +1,11 @@
+fun foo() {
+    val x = 2
+    <caret>if (x <= 1) return
+    // invoke bar1&bar2
+    bar1()
+    bar2()
+    // done
+}
+
+fun bar1(){}
+fun bar2(){}

idea/testData/intentions/invertIfCondition/lastStatement2.kt

@@ -0,0 +1,6 @@
+fun foo() {
+    val x = 2
+    <caret>if (x > 1) bar()
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatement2.kt.after

@@ -0,0 +1,7 @@
+fun foo() {
+    val x = 2
+    <caret>if (x <= 1) return
+    bar()
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatement3.kt

@@ -0,0 +1,8 @@
+fun foo(p: Int) {
+    val x = 2
+    if (p > 0) {
+        <caret>if (x > 1) bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatement3.kt.after

@@ -0,0 +1,9 @@
+fun foo(p: Int) {
+    val x = 2
+    if (p > 0) {
+        <caret>if (x <= 1) return
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementBeforeBreak.kt

@@ -0,0 +1,13 @@
+fun foo() {
+    for (i in 1..10) {
+        if (i > 3) {
+            <caret>if (i > 5) {
+                bar()
+            }
+            break
+        }
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementBeforeBreak.kt.after

@@ -0,0 +1,12 @@
+fun foo() {
+    for (i in 1..10) {
+        if (i > 3) {
+            <caret>if (i <= 5) break
+            bar()
+            break
+        }
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementBeforeContinue.kt

@@ -0,0 +1,13 @@
+fun foo() {
+    for (i in 1..10) {
+        if (i > 3) {
+            <caret>if (i > 5) {
+                bar()
+            }
+            continue
+        }
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementBeforeContinue.kt.after

@@ -0,0 +1,12 @@
+fun foo() {
+    for (i in 1..10) {
+        if (i > 3) {
+            <caret>if (i <= 5) continue
+            bar()
+            continue
+        }
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementBeforeReturn.kt

@@ -0,0 +1,9 @@
+fun foo(p: Boolean): Boolean {
+    val x = 2
+    <caret>if (x > 1) {
+        bar()
+    }
+    return p
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementBeforeReturn.kt.after

@@ -0,0 +1,8 @@
+fun foo(p: Boolean): Boolean {
+    val x = 2
+    <caret>if (x <= 1) return p
+    bar()
+    return p
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementInLambda.kt

@@ -0,0 +1,9 @@
+fun foo() {
+    val v: (Int) -> Unit = {
+        <caret>if (it > 1) {
+            bar()
+        }
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementInLambda.kt.after

@@ -0,0 +1,10 @@
+fun foo() {
+    val v: (Int) -> Unit = {
+        <caret>if (it <= 1) {
+        } else {
+            bar()
+        }
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementInLoop.kt

@@ -0,0 +1,9 @@
+fun foo() {
+    for (i in 1..10) {
+        <caret>if (i > 1) {
+            bar()
+        }
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementInLoop.kt.after

@@ -0,0 +1,8 @@
+fun foo() {
+    for (i in 1..10) {
+        <caret>if (i <= 1) continue
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementNonUnitMethod.kt

@@ -0,0 +1,10 @@
+// ERROR: A 'return' expression required in a function with a block body ('{...}')
+
+fun foo(): Int {
+    val x = 2
+    <caret>if (x > 1) {
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/lastStatementNonUnitMethod.kt.after

@@ -0,0 +1,11 @@
+// ERROR: A 'return' expression required in a function with a block body ('{...}')
+
+fun foo(): Int {
+    val x = 2
+    <caret>if (x <= 1) {
+    } else {
+        bar()
+    }
+}
+
+fun bar(){}

idea/testData/intentions/invertIfCondition/negatedExpression.kt.after

@@ -3,6 +3,5 @@ fun foo(): Boolean {
 }
 
 fun main() {
-    if (foo()) {
-    }
+    if (foo()) return
 }

idea/testData/intentions/invertIfCondition/simple.kt.after

@@ -3,6 +3,5 @@ fun foo(): Boolean {
 }
 
 fun main() {
-    <caret>if (!foo()) {
-    }
+    <caret>if (!foo()) return
 }