K2: support ForbidInferringTypeVariablesIntoEmptyIntersection on/off

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -737,7 +737,9 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
             parameter<FqName>("kotlinClass")
         }
 
-        val INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION by error<PsiElement> {
+        val INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION by deprecationError<PsiElement>(
+            LanguageFeature.ForbidInferringTypeVariablesIntoEmptyIntersection
+        ) {
             parameter<String>("typeVariableDescription")
             parameter<Collection<ConeKotlinType>>("incompatibleTypes")
             parameter<String>("description")

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.builtins.functions.FunctionTypeKind
 import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageFeature.ForbidExposingTypesInPrimaryConstructorProperties
+import org.jetbrains.kotlin.config.LanguageFeature.ForbidInferringTypeVariablesIntoEmptyIntersection
 import org.jetbrains.kotlin.config.LanguageFeature.ForbidUsingExtensionPropertyTypeParameterInDelegate
 import org.jetbrains.kotlin.config.LanguageFeature.ModifierNonBuiltinSuspendFunError
 import org.jetbrains.kotlin.config.LanguageFeature.ProhibitAssigningSingleElementsToVarargsInNamedForm
@@ -433,7 +434,7 @@ object FirErrors {
     val SMARTCAST_IMPOSSIBLE by error4<KtExpression, ConeKotlinType, FirExpression, String, Boolean>()
     val REDUNDANT_NULLABLE by warning0<KtTypeReference>(SourceElementPositioningStrategies.REDUNDANT_NULLABLE)
     val PLATFORM_CLASS_MAPPED_TO_KOTLIN by warning1<PsiElement, FqName>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
-    val INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION by error4<PsiElement, String, Collection<ConeKotlinType>, String, String>()
+    val INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION by deprecationError4<PsiElement, String, Collection<ConeKotlinType>, String, String>(ForbidInferringTypeVariablesIntoEmptyIntersection)
     val INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION by warning4<PsiElement, String, Collection<ConeKotlinType>, String, String>()
     val INCORRECT_LEFT_COMPONENT_OF_INTERSECTION by error0<KtTypeReference>()
     val INCORRECT_RIGHT_COMPONENT_OF_INTERSECTION by error0<KtTypeReference>()

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/coneDiagnosticToFirDiagnostic.kt

@@ -292,8 +292,13 @@ private fun mapInapplicableCandidateError(
                 )
             }
 
-            is InferredEmptyIntersectionDiagnostic -> reportInferredIntoEmptyIntersectionError(
-                source, rootCause.typeVariable, rootCause.incompatibleTypes, rootCause.causingTypes, rootCause.kind
+            is InferredEmptyIntersectionDiagnostic -> reportInferredIntoEmptyIntersection(
+                source,
+                rootCause.typeVariable,
+                rootCause.incompatibleTypes,
+                rootCause.causingTypes,
+                rootCause.kind,
+                isError = rootCause.isError
             )
 
             else -> genericDiagnostic
@@ -434,12 +439,13 @@ private fun ConstraintSystemError.toDiagnostic(
 
         is InferredEmptyIntersection -> {
             @Suppress("UNCHECKED_CAST")
-            reportInferredIntoEmptyIntersectionError(
+            reportInferredIntoEmptyIntersection(
                 source,
                 typeVariable as ConeTypeVariable,
                 incompatibleTypes as Collection<ConeKotlinType>,
                 causingTypes as Collection<ConeKotlinType>,
-                kind
+                kind,
+                this is InferredEmptyIntersectionError,
             )
         }
 
@@ -454,20 +460,24 @@ private fun ConstraintSystemError.toDiagnostic(
     }
 }
 
-private fun reportInferredIntoEmptyIntersectionError(
+private fun reportInferredIntoEmptyIntersection(
     source: KtSourceElement,
     typeVariable: ConeTypeVariable,
     incompatibleTypes: Collection<ConeKotlinType>,
     causingTypes: Collection<ConeKotlinType>,
-    kind: EmptyIntersectionTypeKind
+    kind: EmptyIntersectionTypeKind,
+    isError: Boolean
 ): KtDiagnostic? {
     val typeVariableText =
         (typeVariable.typeConstructor.originalTypeParameter as? ConeTypeParameterLookupTag)?.name?.asString()
             ?: typeVariable.toString()
     val causingTypesText = if (incompatibleTypes == causingTypes) "" else ": ${causingTypes.joinToString()}"
     val factory =
-        if (kind.isDefinitelyEmpty) FirErrors.INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION
-        else FirErrors.INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION
+        when {
+            !kind.isDefinitelyEmpty -> FirErrors.INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION
+            isError -> FirErrors.INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION.errorFactory
+            else -> FirErrors.INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION.warningFactory
+        }
 
     return factory.createOn(source, typeVariableText, incompatibleTypes, kind.description, causingTypesText)
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionStages.kt

@@ -597,7 +597,10 @@ internal object CheckIncompatibleTypeVariableUpperBounds : ResolutionStage() {
                         upperTypes as List<ConeKotlinType>,
                         emptyIntersectionTypeInfo.casingTypes.toList() as List<ConeKotlinType>,
                         variableWithConstraints.typeVariable as ConeTypeVariable,
-                        emptyIntersectionTypeInfo.kind
+                        emptyIntersectionTypeInfo.kind,
+                        isError = context.session.languageVersionSettings.supportsFeature(
+                            LanguageFeature.ForbidInferringTypeVariablesIntoEmptyIntersection
+                        )
                     )
                 )
             }

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionDiagnostic.kt

@@ -33,7 +33,8 @@ class InferredEmptyIntersectionDiagnostic(
     val incompatibleTypes: Collection<ConeKotlinType>,
     val causingTypes: Collection<ConeKotlinType>,
     val typeVariable: ConeTypeVariable,
-    val kind: EmptyIntersectionTypeKind
+    val kind: EmptyIntersectionTypeKind,
+    val isError: Boolean
 ) : ResolutionDiagnostic(INAPPLICABLE)
 
 class TooManyArguments(