org.jetbrains.kotlin.fir.analysis.checkers.expression.FirUselessTypeOperationCallChecker.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2021 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.
*/
package org.jetbrains.kotlin.fir.analysis.checkers.expression
import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
import org.jetbrains.kotlin.diagnostics.reportOn
import org.jetbrains.kotlin.fir.analysis.checkers.isRefinementUseless
import org.jetbrains.kotlin.fir.analysis.checkers.shouldCheckForExactType
import org.jetbrains.kotlin.fir.expressions.*
import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
import org.jetbrains.kotlin.fir.types.*
// See .../types/CastDiagnosticsUtil.kt for counterparts, including isRefinementUseless, isExactTypeCast, isUpcast.
object FirUselessTypeOperationCallChecker : FirTypeOperatorCallChecker() {
override fun check(expression: FirTypeOperatorCall, context: CheckerContext, reporter: DiagnosticReporter) {
if (expression.operation !in FirOperation.TYPES) return
val arg = expression.argument
val candidateType = arg.typeRef.coneType.upperBoundIfFlexible().fullyExpandedType(context.session)
if (candidateType is ConeErrorType) return
val targetType = expression.conversionTypeRef.coneType.fullyExpandedType(context.session)
if (targetType is ConeErrorType) return
// x as? Type <=> x as Type?
val refinedTargetType =
if (expression.operation == FirOperation.SAFE_AS) {
targetType.withNullability(ConeNullability.NULLABLE, context.session.typeContext)
} else {
targetType
}
if (isRefinementUseless(context, candidateType, refinedTargetType, shouldCheckForExactType(expression, context), arg)) {
when (expression.operation) {
FirOperation.IS -> reporter.reportOn(expression.source, FirErrors.USELESS_IS_CHECK, true, context)
FirOperation.NOT_IS -> reporter.reportOn(expression.source, FirErrors.USELESS_IS_CHECK, false, context)
FirOperation.AS, FirOperation.SAFE_AS -> {
if ((arg.typeRef as? FirResolvedTypeRef)?.isFromStubType != true) {
reporter.reportOn(expression.source, FirErrors.USELESS_CAST, context)
}
}
else -> throw AssertionError("Should not be here: ${expression.operation}")
}
}
}
}