io.gitlab.arturbosch.detekt.rules.style.UnnecessaryParentheses.kt Maven / Gradle / Ivy

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package io.gitlab.arturbosch.detekt.rules.style

import io.gitlab.arturbosch.detekt.api.CodeSmell
import io.gitlab.arturbosch.detekt.api.Config
import io.gitlab.arturbosch.detekt.api.Debt
import io.gitlab.arturbosch.detekt.api.Entity
import io.gitlab.arturbosch.detekt.api.Issue
import io.gitlab.arturbosch.detekt.api.Rule
import io.gitlab.arturbosch.detekt.api.Severity
import org.jetbrains.kotlin.psi.KtDelegatedSuperTypeEntry
import org.jetbrains.kotlin.psi.KtParenthesizedExpression
import org.jetbrains.kotlin.psi.KtPsiUtil

/**
 * This rule reports unnecessary parentheses around expressions.
 * These unnecessary parentheses can safely be removed.
 *
 * Added in v1.0.0.RC4
 *
 * 
 * val local = (5 + 3)
 *
 * if ((local == 8)) { }
 *
 * fun foo() {
 *     function({ input -> println(input) })
 * }
 * 
 *
 * 
 * val local = 5 + 3
 *
 * if (local == 8) { }
 *
 * fun foo() {
 *     function { input -> println(input) }
 * }
 * 
 */
class UnnecessaryParentheses(config: Config = Config.empty) : Rule(config) {

    override val issue = Issue(
        "UnnecessaryParentheses",
        Severity.Style,
        "Unnecessary parentheses don't add any value to the code and should be removed.",
        Debt.FIVE_MINS
    )

    override fun visitParenthesizedExpression(expression: KtParenthesizedExpression) {
        super.visitParenthesizedExpression(expression)

        if (expression.expression == null) return

        if (expression.parent is KtDelegatedSuperTypeEntry) return

        if (KtPsiUtil.areParenthesesUseless(expression)) {
            val message = "Parentheses in ${expression.text} are unnecessary and can be replaced with: " +
                "${KtPsiUtil.deparenthesize(expression)?.text}"
            report(CodeSmell(issue, Entity.from(expression), message))
        }
    }
}