Format spaces around ::

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

@@ -252,6 +252,8 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
 
             between(WHEN_ENTRY, WHEN_ENTRY).lineBreakInCode()
 
+            around(COLONCOLON).spaces(0)
+
             around(BY_KEYWORD).spaces(1)
             betweenInside(IDENTIFIER, PROPERTY_DELEGATE, PROPERTY).spaces(1)
         }

idea/testData/formatter/FunctionReferenceOperator.after.kt

@@ -0,0 +1,7 @@
+class Foo {
+    fun bar() {}
+}
+
+fun baz() {
+    Foo::bar
+}

idea/testData/formatter/FunctionReferenceOperator.kt

@@ -0,0 +1,7 @@
+class Foo {
+    fun bar() {}
+}
+
+fun baz() {
+    Foo   ::   bar
+}

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

@@ -326,6 +326,12 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             doTest(fileName);
         }
 
+        @TestMetadata("FunctionReferenceOperator.after.kt")
+        public void testFunctionReferenceOperator() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/FunctionReferenceOperator.after.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("FunctionWithInference.after.kt")
         public void testFunctionWithInference() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/FunctionWithInference.after.kt");