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FIR checker: expose API to check if two types are compatible

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This is useful for quickfixes offering casts. We don't want to offer
user to cast incompatible types.

Also, explicitly allow compare to `Nothing` and handle `Nothing` from intersection
This commit is contained in:
Tianyu Geng
2021-08-03 18:55:47 -07:00
committed by teamcityserver
parent 5b0ca06e95
commit d77db2cda6
13 changed files with 239 additions and 8 deletions
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compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/ConeTypeCompatibilityChecker.kt
+12 -8
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@@ -43,7 +43,7 @@ import org.jetbrains.kotlin.types.Variance
* covariant and contravariant bounds is empty. For example, a range like `[Collection, List]` is empty and hence invalid because `List` is
* not a super class/interface of `Collection`
*/
internal object ConeTypeCompatibilityChecker {
object ConeTypeCompatibilityChecker {
/**
* The result returned by [ConeTypeCompatibilityChecker]. Note the order of enum entries matters.
@@ -63,6 +63,8 @@ internal object ConeTypeCompatibilityChecker {
}
fun ConeInferenceContext.isCompatible(a: ConeKotlinType, b: ConeKotlinType): Compatibility {
// Don't report explicit comparison with `Nothing`
if (a.isNothing || b.isNothing) return Compatibility.COMPATIBLE
if (a is ConeIntersectionType) {
return a.intersectedTypes.minOf { isCompatible(it, b) }
}
@@ -70,11 +72,13 @@ internal object ConeTypeCompatibilityChecker {
return b.intersectedTypes.minOf { isCompatible(a, it) }
}
val intersectionType = intersectTypesOrNull(listOf(a, b)) as? ConeIntersectionType ?: return Compatibility.COMPATIBLE
return intersectionType.intersectedTypes.areCompatible(this)
return when (val intersectionType = intersectTypesOrNull(listOf(a, b))) {
is ConeIntersectionType -> intersectionType.intersectedTypes.getCompatibility(this)
else -> if (intersectionType?.isNothing == true) Compatibility.HARD_INCOMPATIBLE else Compatibility.COMPATIBLE
}
}
private fun Collection<ConeKotlinType>.areCompatible(ctx: ConeInferenceContext): Compatibility {
private fun Collection<ConeKotlinType>.getCompatibility(ctx: ConeInferenceContext): Compatibility {
// If all types are nullable, then `null` makes the given types compatible.
if (all { with(ctx) { it.isNullableType() } }) return Compatibility.COMPATIBLE
@@ -90,7 +94,7 @@ internal object ConeTypeCompatibilityChecker {
// This is to stay compatible with FE1.0.
else -> Compatibility.SOFT_INCOMPATIBLE
}
return ctx.areCompatible(flatMap { it.collectUpperBounds() }.toSet(), emptySet(), compatibilityUpperBound)
return ctx.getCompatibility(flatMap { it.collectUpperBounds() }.toSet(), emptySet(), compatibilityUpperBound)
}
private fun ConeKotlinType.isConcreteType(): Boolean {
@@ -110,7 +114,7 @@ internal object ConeTypeCompatibilityChecker {
* `MyCustom<out Int>`, we let them do so since we do not know what class `MyCustom` uses the type parameter for. Empty containers are
* another example: `emptyList<Int>() == emptyList<String>()`.
*/
private fun ConeInferenceContext.areCompatible(
private fun ConeInferenceContext.getCompatibility(
upperBounds: Set<ConeClassLikeType>,
lowerBounds: Set<ConeClassLikeType>,
compatibilityUpperBound: Compatibility,
@@ -146,7 +150,7 @@ internal object ConeTypeCompatibilityChecker {
val typeArgumentMapping = mutableMapOf<FirTypeParameterSymbol, BoundTypeArguments>().apply {
for (type in upperBounds) {
collectTypeArgumentMapping(type, this@areCompatible, compatibilityUpperBound)
collectTypeArgumentMapping(type, this@getCompatibility, compatibilityUpperBound)
}
}
var result = Compatibility.COMPATIBLE
@@ -158,7 +162,7 @@ internal object ConeTypeCompatibilityChecker {
Compatibility.COMPATIBLE
} else {
checkedTypeParameters.add(paramRef)
areCompatible(upper, lower, compatibility, checkedTypeParameters)
getCompatibility(upper, lower, compatibility, checkedTypeParameters)
}
}
for (compatibility in typeArgsCompatibility) {