Redundant arrow: support removing of 'it ->' #KT-28631 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantLambdaArrowInspection.kt

@@ -30,7 +30,9 @@ class RedundantLambdaArrowInspection : AbstractKotlinInspection() {
             val arrow = functionLiteral.arrow ?: return@lambdaExpressionVisitor
             val parameters = functionLiteral.valueParameters
             val singleParameter = parameters.singleOrNull()
-            if (parameters.isNotEmpty() && singleParameter?.isSingleUnderscore != true) return@lambdaExpressionVisitor
+            if (parameters.isNotEmpty() && singleParameter?.isSingleUnderscore != true && singleParameter?.name != "it") {
+                return@lambdaExpressionVisitor
+            }
 
             if (lambdaExpression.getStrictParentOfType<KtWhenEntry>()?.expression == lambdaExpression) return@lambdaExpressionVisitor
             if (lambdaExpression.getStrictParentOfType<KtContainerNodeForControlStructureBody>()?.let {

idea/testData/inspectionsLocal/redundantLambdaArrow/it.kt

@@ -0,0 +1,10 @@
+fun foo(f: (String) -> Unit) {}
+
+fun print(s: String) {}
+
+fun bar() {
+    foo { <caret>it ->
+        print(it)
+        print(it)
+    }
+}

idea/testData/inspectionsLocal/redundantLambdaArrow/it.kt.after

@@ -0,0 +1,10 @@
+fun foo(f: (String) -> Unit) {}
+
+fun print(s: String) {}
+
+fun bar() {
+    foo {
+        print(it)
+        print(it)
+    }
+}

idea/testData/inspectionsLocal/redundantLambdaArrow/underscore.kt

@@ -1,4 +1,4 @@
-fun foo(f: () -> Unit) {}
+fun foo(f: (String) -> Unit) {}
 
 fun bar() {
     foo { <caret>_ -> }

idea/testData/inspectionsLocal/redundantLambdaArrow/underscore.kt.after

@@ -1,4 +1,4 @@
-fun foo(f: () -> Unit) {}
+fun foo(f: (String) -> Unit) {}
 
 fun bar() {
     foo { <caret>}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -4482,6 +4482,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/inIfWhenEntry2.kt");
         }
 
+        @TestMetadata("it.kt")
+        public void testIt() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/it.kt");
+        }
+
         @TestMetadata("simple.kt")
         public void testSimple() throws Exception {
             runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/simple.kt");