Formatter: Insert new line before/after type alias

#KT-20766 Fixed

idea/formatter/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt

@@ -98,6 +98,7 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
             inPosition(left = PROPERTY, right = FUN).emptyLinesIfLineBreakInLeft(1)
             inPosition(left = FUN, right = PROPERTY).emptyLinesIfLineBreakInLeft(1)
             inPosition(left = SECONDARY_CONSTRUCTOR, right = SECONDARY_CONSTRUCTOR).emptyLinesIfLineBreakInLeft(1)
+            inPosition(left = TYPEALIAS, right = TYPEALIAS).emptyLinesIfLineBreakInLeft(1)
 
             // Case left for alternative constructors
             inPosition(left = FUN, right = CLASS).emptyLinesIfLineBreakInLeft(1)
@@ -179,6 +180,9 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
             between(SECONDARY_CONSTRUCTOR, DECLARATIONS).blankLines(1)
             between(CLASS_INITIALIZER, DECLARATIONS).blankLines(1)
 
+            // TYPEALIAS - TYPEALIAS is an exception
+            between(TYPEALIAS, DECLARATIONS).blankLines(1)
+
             // ENUM_ENTRY - ENUM_ENTRY is exception
             between(ENUM_ENTRY, DECLARATIONS).blankLines(1)
 

idea/testData/formatter/TypeAliasSpacing.after.kt

@@ -0,0 +1,36 @@
+typealias A = Int
+typealias B = Int
+//
+typealias C = Int
+
+typealias D =
+Int
+
+//
+typealias E =
+Int
+
+typealias F = Int
+//
+typealias G = Int
+
+class X
+//
+typealias H = Int
+
+object O
+//
+typealias I = Int
+
+fun foo() {}
+//
+fun foo() {}
+typealias J = Int
+
+//
+class Y
+typealias K = Int
+
+//
+object OO
+typealias L = Int

idea/testData/formatter/TypeAliasSpacing.kt

@@ -0,0 +1,28 @@
+typealias A = Int
+typealias B = Int
+//
+typealias C = Int
+typealias D =
+        Int
+//
+typealias E =
+Int
+typealias F = Int
+//
+typealias G = Int
+class X
+//
+typealias H = Int
+object O
+//
+typealias I = Int
+fun foo() {}
+//
+fun foo() {}
+typealias J = Int
+//
+class Y
+typealias K = Int
+//
+object OO
+typealias L = Int

idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java

@@ -812,6 +812,12 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             doTest(fileName);
         }
 
+        @TestMetadata("TypeAliasSpacing.after.kt")
+        public void testTypeAliasSpacing() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/TypeAliasSpacing.after.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("UnnecessarySpacesInParametersLists.after.kt")
         public void testUnnecessarySpacesInParametersLists() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/UnnecessarySpacesInParametersLists.after.kt");