Add "unnecessary local variable" inspection #KT-15958 Fixed
This commit is contained in:
Mikhail Glukhikh
@@ -0,0 +1,6 @@
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<html>
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<body>
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This inspection reports local variables either used only in the very next return or exact copies of other variables.
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In both cases it's better to inline such a variable.
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</body>
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</html>
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@@ -2400,6 +2400,15 @@
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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.UnnecessaryVariableInspection"
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displayName="Unnecessary local variable"
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groupPath="Kotlin"
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groupName="Redundant constructs"
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enabledByDefault="true"
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level="WEAK WARNING"
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language="kotlin"
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/>
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<referenceImporter implementation="org.jetbrains.kotlin.idea.quickfix.KotlinReferenceImporter"/>
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<referenceImporter implementation="org.jetbrains.kotlin.idea.quickfix.KotlinReferenceImporter"/>
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<fileType.fileViewProviderFactory filetype="KJSM" implementationClass="com.intellij.psi.ClassFileViewProviderFactory"/>
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<fileType.fileViewProviderFactory filetype="KJSM" implementationClass="com.intellij.psi.ClassFileViewProviderFactory"/>
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@@ -0,0 +1,95 @@
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/*
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* Copyright 2010-2017 JetBrains s.r.o.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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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.psi.PsiElementVisitor
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import org.jetbrains.kotlin.descriptors.FunctionDescriptor
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import org.jetbrains.kotlin.descriptors.VariableDescriptor
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import org.jetbrains.kotlin.idea.caches.resolve.analyze
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import org.jetbrains.kotlin.idea.refactoring.inline.KotlinInlineValHandler
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import org.jetbrains.kotlin.psi.KtNameReferenceExpression
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import org.jetbrains.kotlin.psi.KtProperty
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import org.jetbrains.kotlin.psi.KtReturnExpression
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import org.jetbrains.kotlin.psi.KtVisitorVoid
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import org.jetbrains.kotlin.psi.psiUtil.getNextSiblingIgnoringWhitespaceAndComments
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import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
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import org.jetbrains.kotlin.resolve.BindingContext.DECLARATION_TO_DESCRIPTOR
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import org.jetbrains.kotlin.resolve.BindingContext.REFERENCE_TARGET
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class UnnecessaryVariableInspection : AbstractKotlinInspection() {
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override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor =
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object : KtVisitorVoid() {
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override fun visitProperty(property: KtProperty) {
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super.visitProperty(property)
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if (!property.isLocal) return
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val initializer = property.initializer ?: return
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val nameIdentifier = property.nameIdentifier ?: return
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if (!property.isVar && initializer is KtNameReferenceExpression && property.typeReference == null) {
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val context = property.analyze()
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val initializerDescriptor = context[REFERENCE_TARGET, initializer]
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if (initializerDescriptor is VariableDescriptor) {
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if (!initializerDescriptor.isVar &&
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initializerDescriptor.containingDeclaration is FunctionDescriptor) {
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holder.registerProblem(
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nameIdentifier,
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"Variable is an exact copy of another variable and can be inlined",
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ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
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InlineVariableFix()
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)
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return
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}
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}
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}
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val nextStatement = property.getNextSiblingIgnoringWhitespaceAndComments()
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if (nextStatement is KtReturnExpression) {
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val returned = nextStatement.returnedExpression
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if (returned is KtNameReferenceExpression) {
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val context = nextStatement.analyze()
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if (context[REFERENCE_TARGET, returned] == context[DECLARATION_TO_DESCRIPTOR, property]) {
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holder.registerProblem(
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nameIdentifier,
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"Variable used only in following return and can be inlined",
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ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
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InlineVariableFix()
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)
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}
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}
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}
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}
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}
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class InlineVariableFix : LocalQuickFix {
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override fun getName() = "Inline variable"
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override fun getFamilyName() = name
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override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
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val property = descriptor.psiElement.getParentOfType<KtProperty>(strict = true) ?: return
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KotlinInlineValHandler().inlineElement(project, property.findExistingEditor(), property)
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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.UnnecessaryVariableInspection
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@@ -0,0 +1,5 @@
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fun test(): Int {
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val x = 1
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val <caret>y = x
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return x + y
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}
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fun test(): Int {
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val x = 1
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return x + x
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}
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+8
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// PROBLEM: none
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fun test(): Int {
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val x = 1
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// With explicitly given type looks dangerous
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val <caret>y: Int = x
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return x + y
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}
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// PROBLEM: none
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fun test(): Int {
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var x = 1
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val <caret>y = x
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x++
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return x + y
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}
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@@ -0,0 +1,4 @@
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fun sqr(arg: Int): Int {
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val <caret>other = arg
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return other * other
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}
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@@ -0,0 +1,3 @@
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fun sqr(arg: Int): Int {
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return arg * arg
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}
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// PROBLEM: none
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class My(val x: Number)
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fun My.foo(): Int {
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val <caret>y = x
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if (y is Int) return y
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return 0
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}
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fun sum(a: Int, b: Int): Int {
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val <caret>c = a + b
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return c
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}
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fun sum(a: Int, b: Int): Int {
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return a + b
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}
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// PROBLEM: none
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val x: Number? = null
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fun foo(): Int {
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val <caret>y = x
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if (y is Int) return y
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return 0
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}
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// PROBLEM: none
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fun sqrPlusOne(arg: Int): Int {
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var <caret>other = arg
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other++
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return other * other
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}
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@@ -1458,6 +1458,63 @@ 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/unnecessaryVariable")
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@TestDataPath("$PROJECT_ROOT")
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@RunWith(JUnit3RunnerWithInners.class)
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public static class UnnecessaryVariable extends AbstractLocalInspectionTest {
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public void testAllFilesPresentInUnnecessaryVariable() throws Exception {
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KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/inspectionsLocal/unnecessaryVariable"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
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}
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@TestMetadata("copyOfVal.kt")
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public void testCopyOfVal() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/copyOfVal.kt");
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doTest(fileName);
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}
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@TestMetadata("copyOfValWithExplicitType.kt")
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public void testCopyOfValWithExplicitType() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/copyOfValWithExplicitType.kt");
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doTest(fileName);
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}
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@TestMetadata("copyOfVar.kt")
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public void testCopyOfVar() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/copyOfVar.kt");
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doTest(fileName);
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}
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@TestMetadata("paramCopy.kt")
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public void testParamCopy() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/paramCopy.kt");
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doTest(fileName);
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}
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@TestMetadata("propertyCopy.kt")
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public void testPropertyCopy() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/propertyCopy.kt");
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doTest(fileName);
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}
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@TestMetadata("simpleReturn.kt")
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public void testSimpleReturn() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/simpleReturn.kt");
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doTest(fileName);
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}
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@TestMetadata("topLevelCopy.kt")
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public void testTopLevelCopy() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/topLevelCopy.kt");
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doTest(fileName);
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}
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@TestMetadata("varCopy.kt")
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public void testVarCopy() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unnecessaryVariable/varCopy.kt");
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doTest(fileName);
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}
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}
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@TestMetadata("idea/testData/inspectionsLocal/useExpressionBody")
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@TestMetadata("idea/testData/inspectionsLocal/useExpressionBody")
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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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