Add inspection to move the variable declaration into when

#KT-29001 Fixed
2019-02-14 13:25:27 +03:00
parent 7abe9333c8
commit 33954c7632
15 changed files with 220 additions and 0 deletions
@@ -2932,6 +2932,15 @@
                     language="kotlin"
    />
    <localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.MoveVariableDeclarationIntoWhenInspection"
                     displayName="Variable declaration could be moved inside `when`"
                     groupPath="Kotlin"
                     groupName="Style issues"
                     enabledByDefault="true"
                     level="WEAK WARNING"
                     language="kotlin"
    />
    <localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.MainFunctionReturnUnitInspection"
                     displayName="Entry point function should return Unit"
                     groupPath="Kotlin"
@@ -0,0 +1,5 @@
 <html>
 <body>
 This inspection reports the variable declaration that can be moved inside <code>when</code> expression.
 </body>
 </html>
@@ -0,0 +1,55 @@
 /*
 * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
 * that can be found in the license/LICENSE.txt file.
 */
 package org.jetbrains.kotlin.idea.inspections
 import com.intellij.codeInspection.CleanupLocalInspectionTool
 import com.intellij.codeInspection.LocalQuickFix
 import com.intellij.codeInspection.ProblemDescriptor
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiElementVisitor
 import com.intellij.psi.SmartPsiElementPointer
 import org.jetbrains.kotlin.idea.intentions.loopToCallChain.countUsages
 import org.jetbrains.kotlin.idea.intentions.loopToCallChain.previousStatement
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 class MoveVariableDeclarationIntoWhenInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor =
        whenExpressionVisitor(fun(expression: KtWhenExpression) {
            val subjectExpression = expression.subjectExpression ?: return
            val property = expression.findDeclarationNear() ?: return
            if (!property.isUsedOnlyIn(expression)) return
            val identifier = property.nameIdentifier ?: return
            holder.registerProblem(
                property,
                TextRange.from(identifier.startOffsetInParent, identifier.textLength),
                "Variable declaration could be moved inside `when`",
                MoveVariableDeclarationIntoWhenFix(subjectExpression.createSmartPointer())
            )
        })
 }
 private fun KtProperty.isUsedOnlyIn(element: KtElement): Boolean = countUsages() == countUsages(element)
 private fun KtWhenExpression.findDeclarationNear(): KtProperty? {
    val previousProperty = previousStatement() as? KtProperty ?: return null
    return previousProperty.takeIf { !it.isVar && it.hasInitializer() && it.nameIdentifier?.text == subjectExpression?.text }
 }
 private class MoveVariableDeclarationIntoWhenFix(val subjectExpressionPointer: SmartPsiElementPointer<KtExpression>) : LocalQuickFix {
    override fun getName() = "Move the variable into `when`"
    override fun getFamilyName() = name
    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
        val property = descriptor.psiElement as? KtProperty ?: return
        val subjectExpression = subjectExpressionPointer.element ?: return
        subjectExpression.replace(property.copy())
        property.delete()
    }
 }
@@ -0,0 +1 @@
 org.jetbrains.kotlin.idea.inspections.MoveVariableDeclarationIntoWhenInspection
@@ -0,0 +1,11 @@
 // PROBLEM: none
 fun foo() {
    val a = 1
    val b<caret> = 1
    when (a) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -0,0 +1,11 @@
 // PROBLEM: none
 fun foo() {
    val a<caret> = 1
    val b = 42
    when (a) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -0,0 +1,11 @@
 // PROBLEM: none
 fun foo() {
    val a<caret> = 1
    when (a) {
        1 -> {
        }
        else -> {
        }
    }
    val b = a
 }
@@ -0,0 +1,10 @@
 // PROBLEM: none
 fun foo() {
    var a<caret> = 1
    when (a) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -0,0 +1,9 @@
 fun test() = 42
 fun foo() {
    val a<caret> = test()
    when (a) {
        1 -> a
        else -> 24
    }
 }
@@ -0,0 +1,8 @@
 fun test() = 42
 fun foo() {
    when (val a = test()) {
        1 -> a
        else -> 24
    }
 }
@@ -0,0 +1,11 @@
 fun foo() {
    val a<caret> = 1
    // comment
    when (a) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -0,0 +1,10 @@
 fun foo() {
    // comment
    when (val a = 1) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -0,0 +1,11 @@
 fun foo() {
    val a<caret> = 1
    when (a) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -0,0 +1,10 @@
 fun foo() {
    when (val a = 1) {
        1 -> {
        }
        else -> {
        }
    }
 }
@@ -4277,6 +4277,54 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
        }
    }
    @TestMetadata("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen")
    @TestDataPath("$PROJECT_ROOT")
    @RunWith(JUnit3RunnerWithInners.class)
    public static class MoveVariableDeclarationIntoWhen extends AbstractLocalInspectionTest {
        private void runTest(String testDataFilePath) throws Exception {
            KotlinTestUtils.runTest(this::doTest, TargetBackend.ANY, testDataFilePath);
        }
        public void testAllFilesPresentInMoveVariableDeclarationIntoWhen() throws Exception {
            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), TargetBackend.ANY, true);
        }
        @TestMetadata("notApplicableOtherName.kt")
        public void testNotApplicableOtherName() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableOtherName.kt");
        }
        @TestMetadata("notApplicableSideEffect.kt")
        public void testNotApplicableSideEffect() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableSideEffect.kt");
        }
        @TestMetadata("notApplicableUsedInOtherScope.kt")
        public void testNotApplicableUsedInOtherScope() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableUsedInOtherScope.kt");
        }
        @TestMetadata("notApplicableVar.kt")
        public void testNotApplicableVar() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableVar.kt");
        }
        @TestMetadata("simple.kt")
        public void testSimple() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/simple.kt");
        }
        @TestMetadata("withComment.kt")
        public void testWithComment() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/withComment.kt");
        }
        @TestMetadata("withNewLine.kt")
        public void testWithNewLine() throws Exception {
            runTest("idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/withNewLine.kt");
        }
    }
    @TestMetadata("idea/testData/inspectionsLocal/nestedLambdaShadowedImplicitParameter")
    @TestDataPath("$PROJECT_ROOT")
    @RunWith(JUnit3RunnerWithInners.class)
		`@@ -0,0 +1 @@`
							`org.jetbrains.kotlin.idea.inspections.MoveVariableDeclarationIntoWhenInspection`