SetterBackingFieldAssignmentInspection: fix exception

#KT-38520 Fixed

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -10,7 +10,6 @@ import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElementVisitor
 import com.intellij.psi.PsiWhiteSpace
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
-import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.idea.KotlinBundle
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -21,8 +20,8 @@ import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 
 class SetterBackingFieldAssignmentInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
-    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return propertyAccessorVisitor(fun(accessor) {
+    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor =
+        propertyAccessorVisitor(fun(accessor) {
             if (!accessor.isSetter) return
             val bodyExpression = accessor.bodyBlockExpression ?: return
 
@@ -31,24 +30,23 @@ class SetterBackingFieldAssignmentInspection : AbstractKotlinInspection(), Clean
             val propertyDescriptor = propertyContext[BindingContext.DECLARATION_TO_DESCRIPTOR, property] as? PropertyDescriptor ?: return
             if (propertyContext[BindingContext.BACKING_FIELD_REQUIRED, propertyDescriptor] == false) return
 
-            val accessorContext = accessor.analyze()
+            val accessorContext by lazy { accessor.analyze() }
             val parameter = accessor.valueParameters.singleOrNull()
-            val parameterDescriptor = accessorContext[BindingContext.VALUE_PARAMETER, parameter] as? ValueParameterDescriptor
             if (bodyExpression.anyDescendantOfType<KtExpression> {
                     when (it) {
                         is KtBinaryExpression ->
                             it.left.isBackingFieldReference(property) && it.operationToken in assignmentOperators
                         is KtUnaryExpression ->
                             it.baseExpression.isBackingFieldReference(property) && it.operationToken in incrementAndDecrementOperators
-                        is KtCallExpression ->
+                        is KtCallExpression -> {
                             it.valueArguments.any { arg ->
-                                arg.text == parameter?.text && run {
-                                    val argumentResultingDescriptor =
-                                        arg.getArgumentExpression().getResolvedCall(accessorContext)?.resultingDescriptor
-                                    argumentResultingDescriptor == parameterDescriptor
-                                }
+                                val argumentResultingDescriptor = arg.getArgumentExpression()
+                                    .getResolvedCall(accessorContext)
+                                    ?.resultingDescriptor
 
+                                argumentResultingDescriptor != null && argumentResultingDescriptor == accessorContext[BindingContext.VALUE_PARAMETER, parameter]
                             }
+                        }
                         else -> false
                     }
                 }) return
@@ -60,7 +58,6 @@ class SetterBackingFieldAssignmentInspection : AbstractKotlinInspection(), Clean
                 AssignBackingFieldFix()
             )
         })
-    }
 
     private fun KtExpression?.isBackingFieldReference(property: KtProperty) = with(SuspiciousVarPropertyInspection) {
         this@isBackingFieldReference != null && isBackingFieldReference(property)
@@ -85,6 +82,7 @@ private class AssignBackingFieldFix : LocalQuickFix {
             ?.takeWhile { it != bodyExpression.rBrace }
             ?.singleOrNull { it is PsiWhiteSpace }
             ?.also { it.delete() }
-        bodyExpression.addBefore(KtPsiFactory(setter).createExpression("field = ${parameter.text}"), bodyExpression.rBrace)
+
+        bodyExpression.addBefore(KtPsiFactory(setter).createExpression("field = ${parameter.name}"), bodyExpression.rBrace)
     }
 }

idea/testData/inspectionsLocal/setterBackingFieldAssignment/functionCallWithSetterParam2.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+class Test {
+    var foo: Int = 10
+        <caret>set(value: Int) {
+            bar(value = value)
+        }
+
+    fun bar(value: Int) {}
+}

idea/testData/inspectionsLocal/setterBackingFieldAssignment/noAssignment4.kt

@@ -0,0 +1,5 @@
+class Test {
+    var foo: Int = 1
+        <caret>set(value: Int) {
+        }
+}

idea/testData/inspectionsLocal/setterBackingFieldAssignment/noAssignment4.kt.after

@@ -0,0 +1,6 @@
+class Test {
+    var foo: Int = 1
+        set(value: Int) {
+            field = value
+        }
+}

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

@@ -11826,6 +11826,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/setterBackingFieldAssignment/functionCallWithSetterParam.kt");
         }
 
+        @TestMetadata("functionCallWithSetterParam2.kt")
+        public void testFunctionCallWithSetterParam2() throws Exception {
+            runTest("idea/testData/inspectionsLocal/setterBackingFieldAssignment/functionCallWithSetterParam2.kt");
+        }
+
         @TestMetadata("increment.kt")
         public void testIncrement() throws Exception {
             runTest("idea/testData/inspectionsLocal/setterBackingFieldAssignment/increment.kt");
@@ -11861,6 +11866,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/setterBackingFieldAssignment/noAssignment3.kt");
         }
 
+        @TestMetadata("noAssignment4.kt")
+        public void testNoAssignment4() throws Exception {
+            runTest("idea/testData/inspectionsLocal/setterBackingFieldAssignment/noAssignment4.kt");
+        }
+
         @TestMetadata("noBackingField.kt")
         public void testNoBackingField() throws Exception {
             runTest("idea/testData/inspectionsLocal/setterBackingFieldAssignment/noBackingField.kt");