Quick fix for enum entry delimiter syntax fix, together with a set of tests.

Possible NPE in getNextSiblingIgnoringWhitespace fixed. Some warnings also removed.
Last comma is replaced by semicolon. Comments are taken into account.

idea/testData/quickfix/migration/enumDelimiter/commaNoSemicolon.kt

@@ -0,0 +1,7 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, 
+    SECOND<caret>,
+    val zzz = 42
+}

idea/testData/quickfix/migration/enumDelimiter/commaNoSemicolon.kt.after

@@ -0,0 +1,7 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, 
+    SECOND;
+    val zzz = 42
+}

idea/testData/quickfix/migration/enumDelimiter/missedCommas.kt

@@ -0,0 +1,9 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST SECOND,
+    THIRD
+    FOURTH<caret> FIFTH SIXTH,
+    SEVENTH EIGHTH
+
+}

idea/testData/quickfix/migration/enumDelimiter/missedCommas.kt.after

@@ -0,0 +1,9 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, SECOND,
+    THIRD,
+    FOURTH, FIFTH, SIXTH,
+    SEVENTH, EIGHTH
+
+}

idea/testData/quickfix/migration/enumDelimiter/noComma.kt

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST<caret> SECOND
+
+}

idea/testData/quickfix/migration/enumDelimiter/noComma.kt.after

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, SECOND
+
+}

idea/testData/quickfix/migration/enumDelimiter/noCommaComment.kt

@@ -0,0 +1,8 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST<caret>
+    /* The first one */ 
+    SECOND 
+    /* The last one */
+}

idea/testData/quickfix/migration/enumDelimiter/noCommaComment.kt.after

@@ -0,0 +1,8 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST<caret>,
+    /* The first one */ 
+    SECOND 
+    /* The last one */
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiter.kt

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    A B C D<caret> E F G H I J
+    fun foo() = 42
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiter.kt.after

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    A, B, C, D, E, F, G, H, I, J;
+    fun foo() = 42
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiterWithInitializer.kt

@@ -0,0 +1,8 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum(val z: Int) {
+    A: MyEnum(3)
+    B<caret>: MyEnum(7)
+    C: MyEnum(12)
+    fun foo() = z * 2
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiterWithInitializer.kt.after

@@ -0,0 +1,8 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum(val z: Int) {
+    A: MyEnum(3),
+    B: MyEnum(7),
+    C: MyEnum(12);
+    fun foo() = z * 2
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiterWithOverload.kt

@@ -0,0 +1,11 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    A {
+        override fun foo(): Int = 13
+    }
+    B C<caret> {
+        override fun foo(): Int = 23
+    }
+    open fun foo(): Int = 42
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiterWithOverload.kt.after

@@ -0,0 +1,11 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    A {
+        override fun foo(): Int = 13
+    },
+    B, C<caret> {
+        override fun foo(): Int = 23
+    };
+    open fun foo(): Int = 42
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiterWithShortConstructor.kt

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum(val z: Int) {
+    A(3)  B<caret>(7)  C(12)
+    fun foo() = z * 2
+}

idea/testData/quickfix/migration/enumDelimiter/noDelimiterWithShortConstructor.kt.after

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum(val z: Int) {
+    A(3), B(7), C(12);
+    fun foo() = z * 2
+}

idea/testData/quickfix/migration/enumDelimiter/noSemicolon.kt

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, SECOND<caret>
+    val zzz = 42
+}

idea/testData/quickfix/migration/enumDelimiter/noSemicolon.kt.after

@@ -0,0 +1,6 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, SECOND;
+    val zzz = 42
+}

idea/testData/quickfix/migration/enumDelimiter/noSemicolonComment.kt

@@ -0,0 +1,7 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, SECOND<caret>
+    /* The last one*/
+    fun foo() = 1
+}

idea/testData/quickfix/migration/enumDelimiter/noSemicolonComment.kt.after

@@ -0,0 +1,7 @@
+// "Insert lacking comma(s) / semicolon(s)" "true"
+
+enum class MyEnum {
+    FIRST, SECOND<caret>;
+    /* The last one*/
+    fun foo() = 1
+}

idea/testData/quickfix/migration/enumDelimiter/wholeProject.kt

@@ -0,0 +1,22 @@
+// "Insert lacking comma(s) / semicolon(s) in the whole project" "true"
+
+enum class First {
+    RED GREEN,
+    BLUE
+}
+
+enum class Second(val code: Int) {
+    NORTH(2) SOUTH(4),
+    EAST(6) WEST(8)
+}
+
+enum class Third {
+    OK {
+        override fun diag(): String = "OK"
+    }
+    ERROR<caret> {
+        override fun diag(): String = "Failed"
+    }
+    
+    open fun diag(): String = ""
+}

idea/testData/quickfix/migration/enumDelimiter/wholeProject.kt.after

@@ -0,0 +1,22 @@
+// "Insert lacking comma(s) / semicolon(s) in the whole project" "true"
+
+enum class First {
+    RED, GREEN,
+    BLUE
+}
+
+enum class Second(val code: Int) {
+    NORTH(2), SOUTH(4),
+    EAST(6), WEST(8)
+}
+
+enum class Third {
+    OK {
+        override fun diag(): String = "OK"
+    },
+    ERROR {
+        override fun diag(): String = "Failed"
+    };
+
+    open fun diag(): String = ""
+}