From 8a02ce3dc2e82f4e98554f06c41a0f4cb594f7ad Mon Sep 17 00:00:00 2001
From: mglukhikh <glukhikh@mail.ru>
Date: Fri, 31 Mar 2017 13:01:17 +0300
Subject: [PATCH] KT-16828: use _ when appropriate in destructure intention

---
 .../kotlin/idea/intentions/DestructureIntention.kt       | 9 ++++++++-
 .../destructuringInLambda/inspectionData/expected.xml    | 8 ++++++++
 .../intentions/destructuringInLambda/last.kt.after       | 2 +-
 .../intentions/destructuringInLambda/mapIndexedLast.kt   | 5 +++++
 .../destructuringInLambda/mapIndexedLast.kt.after        | 5 +++++
 .../intentions/iterationOverMap/DataClassLast.kt.after   | 2 +-
 .../DataClassNotAllPropertiesUsed.kt.after               | 2 +-
 .../intentions/iterationOverMap/ValueOnly.kt.after       | 2 +-
 .../kotlin/idea/intentions/IntentionTestGenerated.java   | 6 ++++++
 9 files changed, 36 insertions(+), 5 deletions(-)
 create mode 100644 idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt
 create mode 100644 idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt.after

diff --git a/idea/src/org/jetbrains/kotlin/idea/intentions/DestructureIntention.kt b/idea/src/org/jetbrains/kotlin/idea/intentions/DestructureIntention.kt
index ee15047e1b8..67cf99ebba3 100644
--- a/idea/src/org/jetbrains/kotlin/idea/intentions/DestructureIntention.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/intentions/DestructureIntention.kt
@@ -68,8 +68,15 @@ class DestructureIntention : SelfTargetingRangeIntention<KtDeclaration>(
                 excludedDeclarations = usagesToRemove.map { listOfNotNull(it.declarationToDrop) }.flatten()
         )
         val names = ArrayList<String>()
+        val underscoreSupported = element.languageVersionSettings.supportsFeature(LanguageFeature.SingleUnderscoreForParameterName)
         usagesToRemove.forEach { (descriptor, usagesToReplace, variableToDrop, name) ->
-            val suggestedName = name ?: KotlinNameSuggester.suggestNameByName(descriptor.name.asString(), validator)
+            val suggestedName =
+                    if (usagesToReplace.isEmpty() && variableToDrop == null && underscoreSupported) {
+                        "_"
+                    }
+                    else {
+                        name ?: KotlinNameSuggester.suggestNameByName(descriptor.name.asString(), validator)
+                    }
             variableToDrop?.delete()
             usagesToReplace.forEach {
                 it.replace(factory.createExpression(suggestedName))
diff --git a/idea/testData/intentions/destructuringInLambda/inspectionData/expected.xml b/idea/testData/intentions/destructuringInLambda/inspectionData/expected.xml
index 67ff648fbcb..2b9d0973a28 100644
--- a/idea/testData/intentions/destructuringInLambda/inspectionData/expected.xml
+++ b/idea/testData/intentions/destructuringInLambda/inspectionData/expected.xml
@@ -63,4 +63,12 @@
         <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Use destructuring declaration</problem_class>
         <description>Use destructuring declaration</description>
     </problem>
+    <problem>
+        <file>mapIndexedLast.kt</file>
+        <line>5</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/mapIndexedLast.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Use destructuring declaration</problem_class>
+        <description>Use destructuring declaration</description>
+    </problem>
 </problems>
\ No newline at end of file
diff --git a/idea/testData/intentions/destructuringInLambda/last.kt.after b/idea/testData/intentions/destructuringInLambda/last.kt.after
index 718e1b854be..14359ca20e1 100644
--- a/idea/testData/intentions/destructuringInLambda/last.kt.after
+++ b/idea/testData/intentions/destructuringInLambda/last.kt.after
@@ -3,7 +3,7 @@
 data class My(val first: String, val second: Int)
 
 fun foo(list: List<My>) {
-    list.forEach { (first, second) ->
+    list.forEach { (_, second) ->
         println(second)
     }
 }
\ No newline at end of file
diff --git a/idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt b/idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt
new file mode 100644
index 00000000000..5dbc28952e7
--- /dev/null
+++ b/idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt
@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+data class Package(val name: String, val version: String, val source: String, val id: String)
+
+val pkgs = listOf<Package>().mapIndexed { i, <caret>p -> p.id to i }.toMap()
\ No newline at end of file
diff --git a/idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt.after b/idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt.after
new file mode 100644
index 00000000000..83dd45e85cd
--- /dev/null
+++ b/idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt.after
@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+data class Package(val name: String, val version: String, val source: String, val id: String)
+
+val pkgs = listOf<Package>().mapIndexed { i, (_, _, _, id) -> id to i }.toMap()
\ No newline at end of file
diff --git a/idea/testData/intentions/iterationOverMap/DataClassLast.kt.after b/idea/testData/intentions/iterationOverMap/DataClassLast.kt.after
index 8762aec5d14..31e076e9fb1 100644
--- a/idea/testData/intentions/iterationOverMap/DataClassLast.kt.after
+++ b/idea/testData/intentions/iterationOverMap/DataClassLast.kt.after
@@ -3,7 +3,7 @@
 data class My(val first: String, val second: Int)
 
 fun foo(list: List<My>) {
-    for ((first, second) in list) {
+    for ((_, second) in list) {
         println(second)
     }
 }
\ No newline at end of file
diff --git a/idea/testData/intentions/iterationOverMap/DataClassNotAllPropertiesUsed.kt.after b/idea/testData/intentions/iterationOverMap/DataClassNotAllPropertiesUsed.kt.after
index 77dd84aff07..996f048669f 100644
--- a/idea/testData/intentions/iterationOverMap/DataClassNotAllPropertiesUsed.kt.after
+++ b/idea/testData/intentions/iterationOverMap/DataClassNotAllPropertiesUsed.kt.after
@@ -2,7 +2,7 @@
 
 fun main(args: Array<String>) {
     val list = listOf(MyClass(1, 2, 3, 4))
-    for ((a, b, c) in list) {
+    for ((a, _, c) in list) {
         println("$a$c")
     }
 }
diff --git a/idea/testData/intentions/iterationOverMap/ValueOnly.kt.after b/idea/testData/intentions/iterationOverMap/ValueOnly.kt.after
index ef549c73099..78f3a424287 100644
--- a/idea/testData/intentions/iterationOverMap/ValueOnly.kt.after
+++ b/idea/testData/intentions/iterationOverMap/ValueOnly.kt.after
@@ -2,7 +2,7 @@
 
 fun main(args: Array<String>) {
     val map = hashMapOf(1 to 1)
-    for ((key, value) in map) {
+    for ((_, value) in map) {
         println(value)
     }
 }
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
index d23a75da03b..ceee5a951b1 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
@@ -7645,6 +7645,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("mapIndexedLast.kt")
+        public void testMapIndexedLast() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/mapIndexedLast.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("noIt.kt")
         public void testNoIt() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/noIt.kt");