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[FE 1.0] Report USELESS_IS_CHECK if is expression is always false

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^KT-47684 Fixed
This commit is contained in:
Dmitriy Novozhilov
2021-07-09 14:03:48 +03:00
committed by teamcityserver
parent 785e2f862c
commit 7b5a5f5682
24 changed files with 283 additions and 59 deletions
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compiler/frontend/src/org/jetbrains/kotlin/types/expressions/PatternMatchingTypingVisitor.kt
+19 -5
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@@ -43,6 +43,7 @@ import org.jetbrains.kotlin.types.expressions.ControlStructureTypingUtils.*
import org.jetbrains.kotlin.types.expressions.typeInfoFactory.createTypeInfo
import org.jetbrains.kotlin.types.expressions.typeInfoFactory.noTypeInfo
import org.jetbrains.kotlin.types.typeUtil.containsError
import org.jetbrains.kotlin.types.typeUtil.isAnyOrNullableAny
import java.util.*
class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTypingInternals) : ExpressionTypingVisitor(facade) {
@@ -640,9 +641,9 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
assert(element is KtNullableType) { "element must be instance of " + KtNullableType::class.java.name }
context.trace.report(Errors.USELESS_NULLABLE_CHECK.on(element as KtNullableType))
}
checkTypeCompatibility(context, targetType, subjectType, typeReferenceAfterIs)
val typesAreCompatible = checkTypeCompatibility(context, targetType, subjectType, typeReferenceAfterIs)
detectRedundantIs(context, subjectType, targetType, isCheck, negated, subjectDataFlowValue)
detectRedundantIs(context, subjectType, targetType, isCheck, negated, subjectDataFlowValue, typesAreCompatible)
if (context.languageVersionSettings.supportsFeature(LanguageFeature.ProperCheckAnnotationsTargetInTypeUsePositions)) {
components.annotationChecker.check(typeReferenceAfterIs, context.trace)
@@ -662,12 +663,24 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
targetType: KotlinType,
isCheck: KtElement,
negated: Boolean,
subjectDataFlowValue: DataFlowValue
subjectDataFlowValue: DataFlowValue,
typesAreCompatible: Boolean
) {
if (subjectType.containsError() || targetType.containsError()) return
val possibleTypes =
DataFlowAnalyzer.getAllPossibleTypes(subjectType, context, subjectDataFlowValue, context.languageVersionSettings)
if (typesAreCompatible && !targetType.isError) {
val nonTrivialTypes = possibleTypes.filterNot { it.isAnyOrNullableAny() }
.takeIf { it.isNotEmpty() }
?: possibleTypes
if (nonTrivialTypes.none { CastDiagnosticsUtil.isCastPossible(it, targetType, components.platformToKotlinClassMapper) }) {
context.trace.report(USELESS_IS_CHECK.on(isCheck, negated))
}
}
if (CastDiagnosticsUtil.isRefinementUseless(possibleTypes, targetType, false)) {
context.trace.report(Errors.USELESS_IS_CHECK.on(isCheck, !negated))
}
@@ -683,11 +696,11 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
type: KotlinType,
subjectType: KotlinType,
reportErrorOn: KtElement
) {
): Boolean {
// TODO : Take smart casts into account?
if (TypeIntersector.isIntersectionEmpty(type, subjectType)) {
context.trace.report(INCOMPATIBLE_TYPES.on(reportErrorOn, type, subjectType))
return
return false
}
checkEnumsForCompatibility(context, reportErrorOn, subjectType, type)
@@ -696,5 +709,6 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
if (KotlinBuiltIns.isNullableNothing(type) && !TypeUtils.isNullableType(subjectType)) {
context.trace.report(SENSELESS_NULL_IN_WHEN.on(reportErrorOn))
}
return true
}
}