Introduce "Redundant '?: return null'" inspection
#KT-34819 Fixed
This commit is contained in:
Toshiaki Kameyama
committed by
Vladimir Dolzhenko
Vladimir Dolzhenko
parent
5f1cc3b152
commit
820b8c3c54
@@ -3577,6 +3577,15 @@
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language="kotlin"
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language="kotlin"
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/>
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/>
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<localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.RedundantElvisReturnNullInspection"
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displayName="Redundant '?: return null'"
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groupPath="Kotlin"
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groupName="Redundant constructs"
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enabledByDefault="true"
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level="WARNING"
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language="kotlin"
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/>
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<projectService serviceInterface="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"
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<projectService serviceInterface="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"
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serviceImplementation="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"/>
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serviceImplementation="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"/>
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@@ -3578,6 +3578,15 @@
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language="kotlin"
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language="kotlin"
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/>
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/>
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<localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.RedundantElvisReturnNullInspection"
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displayName="Redundant '?: return null'"
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groupPath="Kotlin"
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groupName="Redundant constructs"
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enabledByDefault="true"
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level="WARNING"
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language="kotlin"
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/>
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<projectService serviceInterface="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"
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<projectService serviceInterface="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"
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serviceImplementation="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"/>
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serviceImplementation="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"/>
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@@ -3578,6 +3578,15 @@
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language="kotlin"
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language="kotlin"
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/>
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/>
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<localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.RedundantElvisReturnNullInspection"
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displayName="Redundant '?: return null'"
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groupPath="Kotlin"
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groupName="Redundant constructs"
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enabledByDefault="true"
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level="WARNING"
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language="kotlin"
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/>
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<projectService serviceInterface="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"
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<projectService serviceInterface="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"
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serviceImplementation="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"/>
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serviceImplementation="org.jetbrains.kotlin.idea.codeInsight.KotlinCodeInsightWorkspaceSettings"/>
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@@ -0,0 +1,15 @@
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<html>
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<body>
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This inspection reports redundant '<b>?: return null</b>':
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<br /><br />
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<pre>
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fun foo(): Int? {
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...
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}
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fun test() : Int? {
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return foo() ?: return null
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}
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</pre>
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</body>
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</html>
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@@ -0,0 +1,57 @@
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/*
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* Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
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* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
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*/
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package org.jetbrains.kotlin.idea.inspections
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import com.intellij.codeInspection.LocalQuickFix
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import com.intellij.codeInspection.ProblemDescriptor
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import com.intellij.codeInspection.ProblemHighlightType
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import com.intellij.codeInspection.ProblemsHolder
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import com.intellij.openapi.project.Project
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import com.intellij.openapi.util.TextRange
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import com.intellij.psi.PsiElementVisitor
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import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
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import org.jetbrains.kotlin.lexer.KtTokens
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import org.jetbrains.kotlin.psi.*
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import org.jetbrains.kotlin.psi.psiUtil.endOffset
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import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
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import org.jetbrains.kotlin.psi.psiUtil.startOffset
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class RedundantElvisReturnNullInspection : AbstractKotlinInspection() {
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override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
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return returnExpressionVisitor(fun(returnExpression: KtReturnExpression) {
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if ((returnExpression.returnedExpression?.deparenthesize() as? KtConstantExpression)?.text != KtTokens.NULL_KEYWORD.value) return
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val binaryExpression = returnExpression.getStrictParentOfType<KtBinaryExpression>()?.takeIf {
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it == it.getStrictParentOfType<KtReturnExpression>()?.returnedExpression?.deparenthesize()
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} ?: return
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val right = binaryExpression.right?.deparenthesize()?.takeIf { it == returnExpression } ?: return
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if (binaryExpression.operationToken == KtTokens.ELSE_KEYWORD) return
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if (binaryExpression.left?.resolveToCall()?.resultingDescriptor?.returnType?.isMarkedNullable != true) return
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holder.registerProblem(
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binaryExpression,
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"Redundant '?: return null'",
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ProblemHighlightType.LIKE_UNUSED_SYMBOL,
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TextRange(binaryExpression.operationReference.startOffset, right.endOffset).shiftLeft(binaryExpression.startOffset),
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RemoveRedundantElvisReturnNull()
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)
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})
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}
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private fun KtExpression.deparenthesize() = KtPsiUtil.deparenthesize(this)
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private class RemoveRedundantElvisReturnNull : LocalQuickFix {
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override fun getName() = "Remove redundant '?: return null'"
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override fun getFamilyName() = name
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override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
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val binaryExpression = descriptor.psiElement as? KtBinaryExpression ?: return
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val left = binaryExpression.left ?: return
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binaryExpression.replace(left)
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}
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}
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}
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@@ -0,0 +1 @@
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org.jetbrains.kotlin.idea.inspections.RedundantElvisReturnNullInspection
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@@ -0,0 +1,5 @@
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fun foo(): Int? = null
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fun test() : Int? {
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return foo() <caret>?: return null
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}
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@@ -0,0 +1,5 @@
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fun foo(): Int? = null
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fun test() : Int? {
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return foo()
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}
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@@ -0,0 +1,7 @@
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// PROBLEM: none
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fun foo(): Int? = null
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fun test() : Int? {
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val i = foo() <caret>?: return null
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return 0
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}
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@@ -0,0 +1,6 @@
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// PROBLEM: none
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fun foo(): Int? = null
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fun test() : Int? {
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return foo() <caret>?: return 1
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}
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@@ -0,0 +1,6 @@
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// PROBLEM: none
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fun bar(): Int = 1
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fun test() : Int? {
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return bar() <caret>?: return null // USELESS_ELVIS
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}
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+33
@@ -7144,6 +7144,39 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
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}
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}
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}
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}
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@TestMetadata("idea/testData/inspectionsLocal/redundantElvisReturnNull")
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@TestDataPath("$PROJECT_ROOT")
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@RunWith(JUnit3RunnerWithInners.class)
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public static class RedundantElvisReturnNull extends AbstractLocalInspectionTest {
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private void runTest(String testDataFilePath) throws Exception {
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KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
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}
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public void testAllFilesPresentInRedundantElvisReturnNull() throws Exception {
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KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/inspectionsLocal/redundantElvisReturnNull"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), true);
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}
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@TestMetadata("basic.kt")
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public void testBasic() throws Exception {
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runTest("idea/testData/inspectionsLocal/redundantElvisReturnNull/basic.kt");
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}
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@TestMetadata("notInReturn.kt")
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public void testNotInReturn() throws Exception {
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runTest("idea/testData/inspectionsLocal/redundantElvisReturnNull/notInReturn.kt");
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}
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@TestMetadata("notReturnNull.kt")
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public void testNotReturnNull() throws Exception {
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runTest("idea/testData/inspectionsLocal/redundantElvisReturnNull/notReturnNull.kt");
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}
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@TestMetadata("uselessElvis.kt")
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public void testUselessElvis() throws Exception {
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runTest("idea/testData/inspectionsLocal/redundantElvisReturnNull/uselessElvis.kt");
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}
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}
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@TestMetadata("idea/testData/inspectionsLocal/redundantEmptyInitializerBlock")
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@TestMetadata("idea/testData/inspectionsLocal/redundantEmptyInitializerBlock")
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@TestDataPath("$PROJECT_ROOT")
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@TestDataPath("$PROJECT_ROOT")
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@RunWith(JUnit3RunnerWithInners.class)
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@RunWith(JUnit3RunnerWithInners.class)
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