[FIR] FirCallableSymbol: introduce calculateReturnType

It will help to avoid copy-pasted logic there it is needed

^KT-60728

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirExpressionTypeProvider.kt

@@ -26,7 +26,6 @@ import org.jetbrains.kotlin.fir.references.FirSuperReference
 import org.jetbrains.kotlin.fir.resolve.constructFunctionType
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
-import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi
@@ -179,10 +178,7 @@ internal class KtFirExpressionTypeProvider(
 
     override fun getFunctionalTypeForKtFunction(declaration: KtFunction): KtType {
         val firFunction = declaration.resolveToFirSymbol(firResolveSession, FirResolvePhase.TYPES).fir as FirFunction
-        if (firFunction.returnTypeRef is FirImplicitTypeRef) {
-            firFunction.lazyResolveToPhase(FirResolvePhase.IMPLICIT_TYPES_BODY_RESOLVE)
-        }
-
+        firFunction.symbol.calculateReturnType()
         return firFunction.constructFunctionType(firFunction.specialFunctionTypeKind(firResolveSession.useSiteFirSession)).asKtType()
     }
 

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

@@ -13,22 +13,24 @@ import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.mpp.CallableSymbolMarker
 import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.util.OperatorNameConventions
 
 abstract class FirCallableSymbol<D : FirCallableDeclaration> : FirBasedSymbol<D>(), CallableSymbolMarker {
     abstract val callableId: CallableId
 
     val resolvedReturnTypeRef: FirResolvedTypeRef
         get() {
-            ensureType(fir.returnTypeRef)
-            val returnTypeRef = fir.returnTypeRef
-            if (returnTypeRef !is FirResolvedTypeRef) {
-                errorInLazyResolve("returnTypeRef", returnTypeRef::class, FirResolvedTypeRef::class)
-            }
-
-            return returnTypeRef
+            calculateReturnType()
+            return fir.returnTypeRef as FirResolvedTypeRef
         }
 
+    fun calculateReturnType() {
+        ensureType(fir.returnTypeRef)
+        val returnTypeRef = fir.returnTypeRef
+        if (returnTypeRef !is FirResolvedTypeRef) {
+            errorInLazyResolve("returnTypeRef", returnTypeRef::class, FirResolvedTypeRef::class)
+        }
+    }
+
     val resolvedReturnType: ConeKotlinType
         get() = resolvedReturnTypeRef.coneType