Formatter: support trailing comma in lambda value parameters & fix comments in KtParameter

#KT-34744

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

@@ -609,6 +609,7 @@ abstract class KotlinCommonBlock(
                         node.withTrailingComma,
                         additionalWrap = trailingCommaWrappingStrategyWithMultiLineCheck(LPAR, RPAR)
                     )
+                    FUNCTION_TYPE -> return defaultTrailingCommaWrappingStrategy(LPAR, RPAR)
                     FUNCTION_LITERAL -> {
                         if (nodePsi.parent?.safeAs<KtFunctionLiteral>()?.needTrailingComma(settings) == true) {
                             val check = thisOrPrevIsMultiLineElement(COMMA, LBRACE /* not necessary */, ARROW /* not necessary */)

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

@@ -8,8 +8,10 @@ package org.jetbrains.kotlin.idea.formatter
 import com.intellij.lang.ASTNode
 import com.intellij.openapi.diagnostic.Logger
 import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiComment
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
+import com.intellij.psi.PsiWhiteSpace
 import com.intellij.psi.codeStyle.CodeStyleManager
 import com.intellij.psi.codeStyle.CodeStyleSettings
 import com.intellij.psi.impl.source.codeStyle.PostFormatProcessor
@@ -81,8 +83,9 @@ private class TrailingCommaVisitor(val settings: CodeStyleSettings) : KtTreeVisi
         if (elementType === KtTokens.COMMA || parent.needComma) {
             // add a missing comma
             if (elementType !== KtTokens.COMMA) {
-                changePsi(parent) { element, factory ->
+                changePsi(parent) { factory ->
-                    element.addAfter(factory.createComma(), lastElement)
+                    lastElement.addCommaAfter(factory)
+                    true
                 }
             }
 
@@ -97,31 +100,31 @@ private class TrailingCommaVisitor(val settings: CodeStyleSettings) : KtTreeVisi
             else -> settings.kotlinCustomSettings.ALLOW_TRAILING_COMMA && isMultiline()
         }
 
-    private fun changePsi(element: KtElement, update: (KtElement, KtPsiFactory) -> Unit) {
+    private fun changePsi(element: KtElement, update: (KtPsiFactory) -> Boolean) {
         val oldLength = element.textLength
-        update(element, KtPsiFactory(element))
+        if (update(KtPsiFactory(element))) {
-        val result = CodeStyleManager.getInstance(element.project).reformat(element)
+            val result = CodeStyleManager.getInstance(element.project).reformat(element)
-        myPostProcessor.updateResultRange(oldLength, result.textLength)
+            myPostProcessor.updateResultRange(oldLength, result.textLength)
+        }
     }
 
     private fun correctCommaPosition(parent: KtElement) {
         val invalidElements = parent.firstChild?.siblings(withItself = false)?.mapNotNull {
-            if (it !is ASTNode || it.elementType != KtTokens.COMMA) return@mapNotNull null
+            if (it.safeAs<ASTNode>()?.elementType != KtTokens.COMMA) return@mapNotNull null
-
+            it.createSmartPointer()
-            val prevWithComment = it.getPrevSiblingIgnoringWhitespace(false)
-            val prevWithoutComment = it.getPrevSiblingIgnoringWhitespaceAndComments(false)
-            if (prevWithoutComment?.equals(prevWithComment) == false) {
-                it.createSmartPointer() to prevWithoutComment.createSmartPointer()
-            } else
-                null
         }?.toList() ?: return
 
         if (invalidElements.isNotEmpty()) {
-            changePsi(parent) { element, factory ->
+            changePsi(parent) { factory ->
-                for ((pointToComma, pointToElement) in invalidElements) {
+                var change = false
-                    element.addAfter(factory.createComma(), pointToElement.element)
+                for (pointerToComma in invalidElements) {
-                    pointToComma.element?.delete()
+                    pointerToComma.element?.let {
+                        if (correctComma(it, factory)) {
+                            change = true
+                        }
+                    }
                 }
+                change
             }
         }
     }
@@ -146,6 +149,33 @@ private class TrailingCommaVisitor(val settings: CodeStyleSettings) : KtTreeVisi
     }
 }
 
+private fun PsiElement.addCommaAfter(factory: KtPsiFactory) {
+    val comma = factory.createComma()
+    parent.addAfter(comma, this)
+}
+
+private fun correctComma(comma: PsiElement, factory: KtPsiFactory): Boolean {
+    val prevWithComment = comma.getPrevSiblingIgnoringWhitespace(false)
+    val prevWithoutComment = comma.getPrevSiblingIgnoringWhitespaceAndComments(false)
+    return when {
+        prevWithoutComment?.equals(prevWithComment) == false -> {
+            prevWithoutComment.addCommaAfter(factory)
+            comma.delete()
+            true
+        }
+        prevWithoutComment is KtParameter -> {
+            val check = { element: PsiElement -> element is PsiWhiteSpace || element is PsiComment }
+            val lastElement = prevWithoutComment.lastChild?.takeIf(check) ?: return false
+            val firstElement = lastElement.siblings(forward = false, withItself = true).takeWhile(check).last()
+            comma.parent.addRangeAfter(firstElement, lastElement, comma)
+            prevWithoutComment.deleteChildRange(firstElement, lastElement)
+            true
+        }
+        else ->
+            false
+    }
+}
+
 private val PsiElement.lastCommaOwnerOrComma: PsiElement?
     get() {
         val lastChild = lastSignificantChild ?: return null

idea/testData/formatter/trailingComma/typeParameters/TypeParameterList.after.inv.kt

@@ -239,4 +239,42 @@ class L<
         x : String, y : String, z : String
         >
 
+class C<
+        x : Int // adad
+        >
+
+class G<
+        x : String, y : String, /* */ z : String // adad
+        >
+
+class G<
+        x : String,
+        y : String,
+        /* */ /* */
+        z : String, /**/
+        >()
+
+class H<
+        x : String, /*
+    */
+        y : String,
+        z : String, /*
+    */
+        >
+
+class J<
+        x : String, y : String,
+        z : String, /*
+     */ /**/
+        >
+
+class K<
+        x : String, y : String,
+        z : String, // aw
+        >
+
+class L<
+        x : String, y : String, z : String //awd
+        >
+
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/typeParameters/TypeParameterList.after.kt

@@ -247,4 +247,43 @@ class L<
         x : String, y : String, z : String,
         >
 
+class C<
+        x : Int, // adad
+        >
+
+class G<
+        x : String, y : String, /* */
+        z : String, // adad
+        >
+
+class G<
+        x : String,
+        y : String,
+        /* */ /* */
+        z : String, /**/
+        >()
+
+class H<
+        x : String, /*
+    */
+        y : String,
+        z : String, /*
+    */
+        >
+
+class J<
+        x : String, y : String,
+        z : String, /*
+     */ /**/
+        >
+
+class K<
+        x : String, y : String,
+        z : String, // aw
+        >
+
+class L<
+        x : String, y : String, z : String, //awd
+        >
+
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/typeParameters/TypeParameterList.kt

@@ -226,4 +226,38 @@ class L<
     x: String, y: String, z: String
 >
 
+class C<
+    x: Int // adad
+>
+
+class G<
+    x: String, y: String
+    , /* */ z: String // adad
+>
+
+class G<
+    x: String, y: String
+    /* */, /* */ z: String /**/,
+>()
+
+class H<
+    x: String, /*
+    */ y: String,
+    z: String /*
+    */  ,>
+
+class J<
+    x: String, y: String , z: String /*
+     */
+    , /**/  >
+
+class K<
+    x: String, y: String,
+    z: String // aw
+    ,   >
+
+class L<
+    x: String, y: String, z: String //awd
+>
+
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/LambdaValueParameters.after.inv.kt

@@ -0,0 +1,89 @@
+fun main() {
+    val x: (
+            y: Comparable<Comparable<Number>>,
+            z: Iterable<Iterable<Number>> // trailing comma
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+            z: Iterable<Iterable<Number>>
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>, //
+            z: Iterable<Iterable<Number>> // /**/
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>
+            // wd
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,/*
+    */
+            z: Iterable<Iterable<Number>>, /* //
+    */
+    ) -> Int = {
+        10
+    }
+
+    val x: (/**/y: Comparable<Comparable<Number>>/**/) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,/**/
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>
+    ) -> Int = {
+        10
+    }
+
+    val x: ( /*
+        */y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+}
+
+// SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/LambdaValueParameters.after.kt

@@ -0,0 +1,97 @@
+fun main() {
+    val x: (
+            y: Comparable<Comparable<Number>>,
+            z: Iterable<Iterable<Number>>, // trailing comma
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+            z: Iterable<Iterable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>, //
+            z: Iterable<Iterable<Number>>, // /**/
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+            z: Iterable<Iterable<Number>>,
+            // wd
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,/*
+    */
+            z: Iterable<Iterable<Number>>, /* //
+    */
+    ) -> Int = {
+        10
+    }
+
+    val x: (/**/y: Comparable<Comparable<Number>>/**/) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,/**/
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            y: Comparable<Comparable<Number>>,
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+            /*
+                   */
+            y: Comparable<Comparable<Number>>,
+    ) -> Int = {
+        10
+    }
+}
+
+// SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/LambdaValueParameters.kt

@@ -0,0 +1,80 @@
+fun main() {
+    val x: (
+        y: Comparable<Comparable<Number>>,
+        z: Iterable<Iterable<Number>> // trailing comma
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+        y: Comparable<Comparable<Number>>,
+        z: Iterable<Iterable<Number>>
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>,) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>,) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>
+    ) -> Int = {
+        10
+    }
+
+    val x: (
+        y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+
+    val x: (
+        y: Comparable<Comparable<Number>>, //
+        z: Iterable<Iterable<Number>> // /**/
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>, z: Iterable<Iterable<Number>>
+        // wd
+    ) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>/*
+    */, z: Iterable<Iterable<Number>>, /* //
+    */) -> Int = {
+        10
+    }
+
+    val x: (/**/y: Comparable<Comparable<Number>>/**/) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>/**/,) -> Int = {
+        10
+    }
+
+    val x: (y: Comparable<Comparable<Number>>
+    ) -> Int = {
+        10
+    }
+
+    val x: ( /*
+        */y: Comparable<Comparable<Number>>) -> Int = {
+        10
+    }
+}
+
+// SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListChopAsNeeded.after.inv.kt

@@ -468,8 +468,8 @@ class H(
 
 class J(
         val x: String, val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -478,7 +478,7 @@ class K(
 )
 
 class L(
-        val x: String, val y: String, val z: String
+        val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListChopAsNeeded.after.kt

@@ -462,7 +462,7 @@ class G(
 class G(
         val x: String,
         val y: String
-        = "" /* */, /* */
+        = "", /* */ /* */
         val z: String,
 )
 
@@ -475,8 +475,8 @@ class H(
 
 class J(
         val x: String, val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -485,7 +485,7 @@ class K(
 )
 
 class L(
-        val x: String, val y: String, val z: String,
+        val x: String, val y: String, val z: String, // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListChopAsNeeded.kt

@@ -454,7 +454,7 @@ class K(
     ,   )
 
 class L(
-    val x: String, val y: String, val z: String
+    val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListDoNotWrap.after.inv.kt

@@ -468,8 +468,8 @@ class H(
 
 class J(
         val x: String, val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -478,7 +478,7 @@ class K(
 )
 
 class L(
-        val x: String, val y: String, val z: String
+        val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListDoNotWrap.after.kt

@@ -462,7 +462,7 @@ class G(
 class G(
         val x: String,
         val y: String
-        = "" /* */, /* */
+        = "", /* */ /* */
         val z: String,
 )
 
@@ -475,8 +475,8 @@ class H(
 
 class J(
         val x: String, val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -485,7 +485,7 @@ class K(
 )
 
 class L(
-        val x: String, val y: String, val z: String,
+        val x: String, val y: String, val z: String, // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListDoNotWrap.kt

@@ -454,7 +454,7 @@ class K(
     ,   )
 
 class L(
-    val x: String, val y: String, val z: String
+    val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListWrapAlways.after.inv.kt

@@ -490,8 +490,8 @@ class H(
 class J(
         val x: String,
         val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -503,7 +503,7 @@ class K(
 class L(
         val x: String,
         val y: String,
-        val z: String
+        val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListWrapAlways.after.kt

@@ -477,7 +477,7 @@ class G(
 class G(
         val x: String,
         val y: String
-        = "" /* */, /* */
+        = "", /* */ /* */
         val z: String,
 )
 
@@ -491,8 +491,8 @@ class H(
 class J(
         val x: String,
         val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -504,7 +504,7 @@ class K(
 class L(
         val x: String,
         val y: String,
-        val z: String,
+        val z: String, // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListWrapAlways.kt

@@ -454,7 +454,7 @@ class K(
     ,   )
 
 class L(
-    val x: String, val y: String, val z: String
+    val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListWrapAsNeeded.after.inv.kt

@@ -468,8 +468,8 @@ class H(
 
 class J(
         val x: String, val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -478,7 +478,7 @@ class K(
 )
 
 class L(
-        val x: String, val y: String, val z: String
+        val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListWrapAsNeeded.after.kt

@@ -462,7 +462,7 @@ class G(
 class G(
         val x: String,
         val y: String
-        = "" /* */, /* */
+        = "", /* */ /* */
         val z: String,
 )
 
@@ -475,8 +475,8 @@ class H(
 
 class J(
         val x: String, val y: String,
-        val z: String /*
+        val z: String, /*
-     */,
+     */
 )
 
 class K(
@@ -485,7 +485,7 @@ class K(
 )
 
 class L(
-        val x: String, val y: String, val z: String,
+        val x: String, val y: String, val z: String, // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

idea/testData/formatter/trailingComma/valueParameters/ParameterListWrapAsNeeded.kt

@@ -454,7 +454,7 @@ class K(
     ,   )
 
 class L(
-    val x: String, val y: String, val z: String
+    val x: String, val y: String, val z: String // adwd
 )
 
 // SET_TRUE: ALLOW_TRAILING_COMMA

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

@@ -1299,6 +1299,11 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
                     KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/formatter/trailingComma/valueParameters"), Pattern.compile("^([^\\.]+)\\.after\\.kt.*$"), null, true);
                 }
 
+                @TestMetadata("LambdaValueParameters.after.kt")
+                public void testLambdaValueParameters() throws Exception {
+                    runTest("idea/testData/formatter/trailingComma/valueParameters/LambdaValueParameters.after.kt");
+                }
+
                 @TestMetadata("ParameterListChopAsNeeded.after.kt")
                 public void testParameterListChopAsNeeded() throws Exception {
                     runTest("idea/testData/formatter/trailingComma/valueParameters/ParameterListChopAsNeeded.after.kt");
@@ -1851,6 +1856,11 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
                     KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/formatter/trailingComma/valueParameters"), Pattern.compile("^([^\\.]+)\\.after\\.inv\\.kt.*$"), null, true);
                 }
 
+                @TestMetadata("LambdaValueParameters.after.inv.kt")
+                public void testLambdaValueParameters() throws Exception {
+                    runTest("idea/testData/formatter/trailingComma/valueParameters/LambdaValueParameters.after.inv.kt");
+                }
+
                 @TestMetadata("ParameterListChopAsNeeded.after.inv.kt")
                 public void testParameterListChopAsNeeded() throws Exception {
                     runTest("idea/testData/formatter/trailingComma/valueParameters/ParameterListChopAsNeeded.after.inv.kt");