[FIR] ReturnTypeCalculatorWithJump: support WrappedIntegerOperator explicitly

^KTIJ-25761

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

@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.fir.resolve.transformers.contracts.runContractResolv
 import org.jetbrains.kotlin.fir.scopes.FakeOverrideTypeCalculator
 import org.jetbrains.kotlin.fir.scopes.fakeOverrideSubstitution
 import org.jetbrains.kotlin.fir.delegatedWrapperData
+import org.jetbrains.kotlin.fir.scopes.impl.originalForWrappedIntegerOperator
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirSyntheticPropertySymbol
 import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
@@ -202,6 +203,14 @@ open class ReturnTypeCalculatorWithJump(
             )
         }
 
+        if (declaration is FirSimpleFunction) {
+            // Effectively this logic is redundant now, because all methods of Int have an explicit return type,
+            // so explicit call here just to be sure (probably some method from Int will have an implicit type)
+            declaration.originalForWrappedIntegerOperator?.let {
+                tryCalculateReturnTypeOrNull(it.fir)
+            }
+        }
+
         resolvedToContractsIfNecessary(declaration)
 
         val returnTypeRef = declaration.returnTypeRef