Refactoring: get rid of firSafeNullable, enhance getSymbolByLookupTag

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirResolvedCallableReference.kt

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.visitors.FirVisitor
 
 interface FirResolvedCallableReference : FirNamedReference {
+    // Can't write FirCallableSymbol here because of enums
     val resolvedSymbol: AbstractFirBasedSymbol<*>
 
     override fun <R, D> accept(visitor: FirVisitor<R, D>, data: D): R =

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/ConeClassLikeLookupTagImpl.kt

@@ -9,7 +9,7 @@ import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
 import org.jetbrains.kotlin.name.ClassId
 
 class ConeClassLikeLookupTagImpl(override val classId: ClassId) : ConeClassLikeLookupTag() {
-    var boundSymbol: Pair<*, FirClassifierSymbol<*>?>? = null
+    var boundSymbol: Pair<*, FirClassLikeSymbol<*>?>? = null
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true