Removed useless as casts from compiler code

It allows compiling code with K2 and enabled `-Werror`

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

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.fir.resolve.inference.model.ConeReceiverConstraintPo
 import org.jetbrains.kotlin.fir.resolve.inference.preprocessCallableReference
 import org.jetbrains.kotlin.fir.resolve.inference.preprocessLambdaArgument
 import org.jetbrains.kotlin.fir.resolve.transformers.ReturnTypeCalculator
-import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
 import org.jetbrains.kotlin.fir.resolve.transformers.ensureResolvedTypeDeclaration
 import org.jetbrains.kotlin.fir.returnExpressions
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
@@ -362,9 +361,7 @@ private fun checkApplicabilityForArgumentType(
                     return ConeTypeIntersector.intersectTypes(context.session.typeContext, constraintTypes)
                 }
 
-                val originalTypeParameter =
-                    (lookupTag as? ConeTypeVariableTypeConstructor)?.originalTypeParameter as? ConeTypeParameterLookupTag
-
+                val originalTypeParameter = lookupTag.originalTypeParameter as? ConeTypeParameterLookupTag
                 if (originalTypeParameter != null)
                     return ConeTypeParameterTypeImpl(originalTypeParameter, type.isNullable, type.attributes)
             } else if (type is ConeIntegerLiteralType) {

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

@@ -10,7 +10,6 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.isClass
 import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
-import org.jetbrains.kotlin.fir.declarations.FirVariable
 import org.jetbrains.kotlin.fir.declarations.utils.modality
 import org.jetbrains.kotlin.fir.dispatchReceiverClassLookupTagOrNull
 import org.jetbrains.kotlin.fir.expressions.FirFunctionCall
@@ -27,7 +26,6 @@ import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.types.AbstractTypeChecker
 import org.jetbrains.kotlin.utils.SmartList
-import org.jetbrains.kotlin.utils.addIfNotNull
 
 fun BodyResolveComponents.findTypesForSuperCandidates(
     superTypeRefs: List<FirTypeRef>,
@@ -144,7 +142,7 @@ private fun BodyResolveComponents.getPropertyMembers(type: ConeKotlinType, name:
             scopeSession = scopeSession,
             callableCopyTypeCalculator = CallableCopyTypeCalculator.DoNothing,
             requiredMembersPhase = FirResolvePhase.STATUS,
-        )?.processPropertiesByName(name) { addIfNotNull(it.fir as? FirVariable) }
+        )?.processPropertiesByName(name) { add(it.fir) }
     }
 
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/ConstraintSystemCompleter.kt

@@ -421,7 +421,7 @@ class ConstraintSystemCompleter(components: BodyResolveComponents, private val c
                     processBlocks = true
                 ) { candidate ->
                     candidate.postponedAtoms.forEach { atom ->
-                        notAnalyzedArguments.addIfNotNull((atom as? PostponedResolvedAtom)?.takeUnless { it.analyzed })
+                        notAnalyzedArguments.addIfNotNull(atom.takeUnless { it.analyzed })
                     }
                 }
             }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt

@@ -1027,7 +1027,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             ),
         )
 
-        (result as? FirVariableAssignment)?.let { dataFlowAnalyzer.exitVariableAssignment(it) }
+        dataFlowAnalyzer.exitVariableAssignment(result)
 
         return result
     }