From f1c605d0f72eeb670145e6a0ca987d4510759e3c Mon Sep 17 00:00:00 2001
From: Toshiaki Kameyama <kmymtsak@gmail.com>
Date: Wed, 30 Oct 2019 22:49:20 +0900
Subject: [PATCH] AddFunctionParametersFix: improve parameter name for 'it'
 argument

#KT-33297 Fixed
---
 .../kotlin/idea/quickfix/ChangeFunctionSignatureFix.kt    | 7 +++++++
 .../quickfix/changeSignature/addForItParameter.kt         | 8 ++++++++
 .../quickfix/changeSignature/addForItParameter.kt.after   | 8 ++++++++
 .../kotlin/idea/quickfix/QuickFixTestGenerated.java       | 5 +++++
 4 files changed, 28 insertions(+)
 create mode 100644 idea/testData/quickfix/changeSignature/addForItParameter.kt
 create mode 100644 idea/testData/quickfix/changeSignature/addForItParameter.kt.after

diff --git a/idea/src/org/jetbrains/kotlin/idea/quickfix/ChangeFunctionSignatureFix.kt b/idea/src/org/jetbrains/kotlin/idea/quickfix/ChangeFunctionSignatureFix.kt
index 5a47575f507..c64cab02b3e 100644
--- a/idea/src/org/jetbrains/kotlin/idea/quickfix/ChangeFunctionSignatureFix.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/quickfix/ChangeFunctionSignatureFix.kt
@@ -40,6 +40,7 @@ import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.ValueArgument
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.resolve.calls.callUtil.getCall
+import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 
@@ -64,6 +65,12 @@ abstract class ChangeFunctionSignatureFix(
             argumentName != null -> KotlinNameSuggester.suggestNameByName(argumentName.asName.asString(), validator)
             expression != null -> {
                 val bindingContext = expression.analyze(BodyResolveMode.PARTIAL)
+                if (expression.text == "it") {
+                    val type = expression.getType(bindingContext)
+                    if (type != null) {
+                        return KotlinNameSuggester.suggestNamesByType(type, validator, "param").first()
+                    }
+                }
                 KotlinNameSuggester.suggestNamesByExpressionAndType(expression, null, bindingContext, validator, "param").first()
             }
             else -> KotlinNameSuggester.suggestNameByName("param", validator)
diff --git a/idea/testData/quickfix/changeSignature/addForItParameter.kt b/idea/testData/quickfix/changeSignature/addForItParameter.kt
new file mode 100644
index 00000000000..28d3dbfe8d2
--- /dev/null
+++ b/idea/testData/quickfix/changeSignature/addForItParameter.kt
@@ -0,0 +1,8 @@
+// "Add parameter to constructor 'Foo'" "true"
+// WITH_RUNTIME
+
+class Foo
+
+fun test(name: String) {
+    name.also { Foo(it<caret>) }
+}
\ No newline at end of file
diff --git a/idea/testData/quickfix/changeSignature/addForItParameter.kt.after b/idea/testData/quickfix/changeSignature/addForItParameter.kt.after
new file mode 100644
index 00000000000..c89bfc90e8c
--- /dev/null
+++ b/idea/testData/quickfix/changeSignature/addForItParameter.kt.after
@@ -0,0 +1,8 @@
+// "Add parameter to constructor 'Foo'" "true"
+// WITH_RUNTIME
+
+class Foo(s: String)
+
+fun test(name: String) {
+    name.also { Foo(it) }
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java
index d6cbca0fd71..69af5f5ce7b 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java
@@ -2185,6 +2185,11 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             runTest("idea/testData/quickfix/changeSignature/addEnumConstructorParameter5.kt");
         }
 
+        @TestMetadata("addForItParameter.kt")
+        public void testAddForItParameter() throws Exception {
+            runTest("idea/testData/quickfix/changeSignature/addForItParameter.kt");
+        }
+
         @TestMetadata("addFunctionParameter.kt")
         public void testAddFunctionParameter() throws Exception {
             runTest("idea/testData/quickfix/changeSignature/addFunctionParameter.kt");