Format spaces in infix call (KT-12018)

#KT-12018 Fixed

ChangeLog.md

@@ -43,6 +43,7 @@ Issues fixed:
 - [KT-10950](https://youtrack.jetbrains.com/issue/KT-10950) Keep original file package name when moving top-level declarations to separate file (provided it's not ambiguous)
 - [KT-10174](https://youtrack.jetbrains.com/issue/KT-10174) Optimize imports after applying "Move declaration to separate file" intention
 - [KT-12035](https://youtrack.jetbrains.com/issue/KT-12035) Auto-format cast expressions
+- [KT-12018](https://youtrack.jetbrains.com/issue/KT-12018) Auto-format spaces between function name and arguments in infix calls
 
 #### Debugger
 

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

@@ -165,6 +165,7 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
             afterInside(IDENTIFIER, FUN).spacing(0, 0, 0, false, 0)
 
             around(AS_KEYWORD).spaces(1)
+            aroundInside(IDENTIFIER, BINARY_EXPRESSION).spaces(1)
 
             // before LPAR in constructor(): this() {}
             after(CONSTRUCTOR_DELEGATION_REFERENCE).spacing(0, 0, 0, false, 0)

idea/testData/formatter/InfixCall.after.kt

@@ -0,0 +1,3 @@
+fun foo() {
+    val a = 1 shl 2
+}

idea/testData/formatter/InfixCall.kt

@@ -0,0 +1,3 @@
+fun foo() {
+    val a = 1  shl   2
+}

idea/testData/refactoring/extractFunction/parameters/misc/addPrefixToBackticks.kt.after

@@ -12,5 +12,5 @@ class Y(val y: Int) {
 }
 
 private fun __dummyTestFun__(x1: X, y1: Y) {
-    x1.`x`plus y1.y
+    x1.`x` plus y1.y
 }

idea/testData/refactoring/extractFunction/parameters/misc/idWithBackticks.kt.after

@@ -6,5 +6,5 @@ fun test() {
 }
 
 private fun __dummyTestFun__(`i`: Int) {
-    `i`plus i
+    `i` plus i
 }

idea/testData/refactoring/extractFunction/parameters/misc/idWithRequiredBackticks.kt.after

@@ -6,5 +6,5 @@ fun test() {
 }
 
 private fun __dummyTestFun__(`0`: Int) {
-    `0`plus 1
+    `0` plus 1
 }

idea/testData/refactoring/extractFunction/parameters/misc/replaceWithBackticks.kt.after

@@ -6,5 +6,5 @@ fun test() {
 }
 
 private fun __dummyTestFun__(i: Int) {
-    `i`plus i
+    `i` plus i
 }

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

@@ -343,6 +343,12 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             doTest(fileName);
         }
 
+        @TestMetadata("InfixCall.after.kt")
+        public void testInfixCall() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/InfixCall.after.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("KDoc.after.kt")
         public void testKDoc() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/KDoc.after.kt");