From 2a7eb2fb0e388a97ccd19dab409c640fc0bb3054 Mon Sep 17 00:00:00 2001
From: Toshiaki Kameyama <kmymtsak@gmail.com>
Date: Sun, 3 Feb 2019 00:28:04 +0900
Subject: [PATCH] Redundant lambda arrow: do not report on nested lambda

#KT-29093 Fixed
---
 .../inspections/RedundantLambdaArrowInspection.kt |  9 +++++++++
 .../redundantLambdaArrow/nestedLambda.kt          |  7 +++++++
 .../redundantLambdaArrow/nestedLambda2.kt         |  9 +++++++++
 .../redundantLambdaArrow/nestedLambda3.kt         |  9 +++++++++
 .../redundantLambdaArrow/nestedLambda3.kt.after   |  9 +++++++++
 .../inspections/LocalInspectionTestGenerated.java | 15 +++++++++++++++
 6 files changed, 58 insertions(+)
 create mode 100644 idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda.kt
 create mode 100644 idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda2.kt
 create mode 100644 idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt
 create mode 100644 idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt.after

diff --git a/idea/src/org/jetbrains/kotlin/idea/inspections/RedundantLambdaArrowInspection.kt b/idea/src/org/jetbrains/kotlin/idea/inspections/RedundantLambdaArrowInspection.kt
index afff0f7f0ca..07cdde274c8 100644
--- a/idea/src/org/jetbrains/kotlin/idea/inspections/RedundantLambdaArrowInspection.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/inspections/RedundantLambdaArrowInspection.kt
@@ -16,7 +16,9 @@ import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.KtNodeTypes
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
+import org.jetbrains.kotlin.idea.search.usagesSearch.descriptor
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.anyDescendantOfType
 import org.jetbrains.kotlin.psi.psiUtil.endOffset
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.startOffset
@@ -59,6 +61,13 @@ class RedundantLambdaArrowInspection : AbstractKotlinInspection() {
                 if (argumentMatch?.valueParameter?.original?.type?.isTypeParameter() == true) return
             }
 
+            val functionLiteralDescriptor = functionLiteral.descriptor
+            if (functionLiteralDescriptor != null) {
+                if (functionLiteral.anyDescendantOfType<KtNameReferenceExpression> {
+                        it.text == "it" && it.resolveToCall()?.resultingDescriptor?.containingDeclaration != functionLiteralDescriptor
+                    }) return
+            }
+
             val startOffset = functionLiteral.startOffset
             holder.registerProblem(
                 holder.manager.createProblemDescriptor(
diff --git a/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda.kt b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda.kt
new file mode 100644
index 00000000000..e4f80c8b3f5
--- /dev/null
+++ b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda.kt
@@ -0,0 +1,7 @@
+// PROBLEM: none
+// WITH_RUNTIME
+fun test() {
+    listOf("A").forEach {
+        setOf(1).map { <caret>_ -> it.length }
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda2.kt b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda2.kt
new file mode 100644
index 00000000000..649cfcbfd49
--- /dev/null
+++ b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda2.kt
@@ -0,0 +1,9 @@
+// PROBLEM: none
+// WITH_RUNTIME
+fun test() {
+    listOf("A").forEach {
+        listOf("B").forEach { _ ->
+            setOf(1).map { <caret>_ -> it.length }
+        }
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt
new file mode 100644
index 00000000000..b335048e90a
--- /dev/null
+++ b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt
@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+fun test() {
+    listOf("A").forEach {
+        setOf(1).map { <caret>_ ->
+            val it = "B"
+            it.length
+        }
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt.after b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt.after
new file mode 100644
index 00000000000..0b7fcfbede2
--- /dev/null
+++ b/idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt.after
@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+fun test() {
+    listOf("A").forEach {
+        setOf(1).map {
+            val it = "B"
+            it.length
+        }
+    }
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
index 1aa13b2a769..2a1de9df46c 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
@@ -5009,6 +5009,21 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/it.kt");
         }
 
+        @TestMetadata("nestedLambda.kt")
+        public void testNestedLambda() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda.kt");
+        }
+
+        @TestMetadata("nestedLambda2.kt")
+        public void testNestedLambda2() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda2.kt");
+        }
+
+        @TestMetadata("nestedLambda3.kt")
+        public void testNestedLambda3() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/nestedLambda3.kt");
+        }
+
         @TestMetadata("noExpectedType.kt")
         public void testNoExpectedType() throws Exception {
             runTest("idea/testData/inspectionsLocal/redundantLambdaArrow/noExpectedType.kt");