[NI] discriminate Nothing for reified parameters

Related issues: KT-32836, KT-35728

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ResultTypeResolver.kt

@@ -22,11 +22,8 @@ import org.jetbrains.kotlin.resolve.calls.inference.components.TypeVariableDirec
 import org.jetbrains.kotlin.resolve.calls.inference.model.*
 import org.jetbrains.kotlin.types.AbstractTypeApproximator
 import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
-import org.jetbrains.kotlin.types.model.KotlinTypeMarker
-import org.jetbrains.kotlin.types.model.TypeVariableMarker
+import org.jetbrains.kotlin.types.model.*
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-import org.jetbrains.kotlin.types.model.TypeSubstitutorMarker
-import org.jetbrains.kotlin.types.model.TypeSystemInferenceExtensionContext
 
 class ResultTypeResolver(
     val typeApproximator: AbstractTypeApproximator,
@@ -35,6 +32,7 @@ class ResultTypeResolver(
     interface Context : TypeSystemInferenceExtensionContext {
         fun isProperType(type: KotlinTypeMarker): Boolean
         fun buildNotFixedVariablesToStubTypesSubstitutor(): TypeSubstitutorMarker
+        fun isReified(variable: TypeVariableMarker): Boolean
     }
 
     fun findResultType(c: Context, variableWithConstraints: VariableWithConstraints, direction: ResolveDirection): KotlinTypeMarker {
@@ -85,6 +83,7 @@ class ResultTypeResolver(
         }
         if (!trivialConstraintTypeInferenceOracle.isSuitableResultedType(resultType)) {
             if (resultType.isNullableType() && checkSingleLowerNullabilityConstraint(filteredConstraints)) return false
+            if (isReified(variableWithConstraints.typeVariable)) return false
         }
 
         return true

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/VariableFixationFinder.kt

@@ -33,6 +33,7 @@ class VariableFixationFinder(
     interface Context : TypeSystemInferenceExtensionContext {
         val notFixedTypeVariables: Map<TypeConstructorMarker, VariableWithConstraints>
         val postponedTypeVariables: List<TypeVariableMarker>
+        fun isReified(variable: TypeVariableMarker): Boolean
     }
 
     data class VariableForFixation(
@@ -56,6 +57,7 @@ class VariableFixationFinder(
         WITH_TRIVIAL_OR_NON_PROPER_CONSTRAINTS, // proper trivial constraint from arguments, Nothing <: T
         RELATED_TO_ANY_OUTPUT_TYPE,
         READY_FOR_FIXATION,
+        READY_FOR_FIXATION_REIFIED,
     }
 
     private fun Context.getTypeVariableReadiness(
@@ -68,6 +70,7 @@ class VariableFixationFinder(
         hasDependencyToOtherTypeVariables(variable) -> TypeVariableFixationReadiness.WITH_COMPLEX_DEPENDENCY
         variableHasTrivialOrNonProperConstraints(variable) -> TypeVariableFixationReadiness.WITH_TRIVIAL_OR_NON_PROPER_CONSTRAINTS
         dependencyProvider.isVariableRelatedToAnyOutputType(variable) -> TypeVariableFixationReadiness.RELATED_TO_ANY_OUTPUT_TYPE
+        isReified(variable) -> TypeVariableFixationReadiness.READY_FOR_FIXATION_REIFIED
         else -> TypeVariableFixationReadiness.READY_FOR_FIXATION
     }
 
@@ -121,4 +124,6 @@ class VariableFixationFinder(
     private fun Context.isProperType(type: KotlinTypeMarker): Boolean =
         !type.contains { notFixedTypeVariables.containsKey(it.typeConstructor()) }
 
+    private fun Context.isReified(variable: TypeConstructorMarker): Boolean =
+        notFixedTypeVariables[variable]?.typeVariable?.let { isReified(it) } ?: false
 }

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/model/NewConstraintSystemImpl.kt

@@ -341,6 +341,12 @@ class NewConstraintSystemImpl(
         return storage.buildNotFixedVariablesToNonSubtypableTypesSubstitutor(this)
     }
 
+    // ResultTypeResolver.Context, VariableFixationFinder.Context
+    override fun isReified(variable: TypeVariableMarker): Boolean {
+        if (variable !is TypeVariableFromCallableDescriptor) return false
+        return variable.originalTypeParameter.isReified
+    }
+
     override fun bindingStubsForPostponedVariables(): Map<TypeVariableMarker, StubTypeMarker> {
         checkState(State.BUILDING, State.COMPLETION)
         // TODO: SUB