Do necessary down casts when generating method calls

Author: IlyaMuravjov

utbot-framework/src/main/kotlin/org/utbot/framework/codegen/services/access/CgCallableAccessManager.kt

@@ -29,6 +29,7 @@ import org.utbot.framework.codegen.domain.models.CgVariable
 import org.utbot.framework.codegen.services.access.CgCallableAccessManagerImpl.FieldAccessorSuitability.*
 import org.utbot.framework.codegen.tree.CgComponents.getStatementConstructorBy
 import org.utbot.framework.codegen.tree.CgComponents.getVariableConstructorBy
+import org.utbot.framework.codegen.tree.downcastIfNeeded
 import org.utbot.framework.codegen.tree.getAmbiguousOverloadsOf
 import org.utbot.framework.codegen.tree.importIfNeeded
 import org.utbot.framework.codegen.tree.isUtil
@@ -114,7 +115,11 @@ internal class CgCallableAccessManagerImpl(val context: CgContext) : CgCallableA
  override operator fun CgIncompleteMethodCall.invoke(vararg args: Any?): CgMethodCall {
  val resolvedArgs = args.resolve()
  val methodCall = if (method.canBeCalledWith(caller, resolvedArgs)) {
- CgMethodCall(caller, method, resolvedArgs.guardedForDirectCallOf(method)).takeCallerFromArgumentsIfNeeded()
+ CgMethodCall(
+ caller = caller?.let { downcastIfNeeded(method.classId, caller) },
+ executableId = method,
+ arguments = resolvedArgs.guardedForDirectCallOf(method)
+ ).takeCallerFromArgumentsIfNeeded()
  } else {
  method.callWithReflection(caller, resolvedArgs)
  }
@@ -200,7 +205,8 @@ internal class CgCallableAccessManagerImpl(val context: CgContext) : CgCallableA
  // this executable can be called on builtin type
  this.type is BuiltinClassId && this.type in builtinCallersWithoutReflection -> true
 
- else -> false
+ // receiver can be downcasted before call
+ else -> executable.isAccessibleFrom(testClassPackageName)
  }
 
  // For some builtin types we need to clarify

utbot-framework/src/main/kotlin/org/utbot/framework/codegen/tree/CgMethodConstructor.kt

@@ -1159,7 +1159,7 @@ open class CgMethodConstructor(val context: CgContext) : CgContextOwner by conte
  } else if (context.codegenLanguage == CodegenLanguage.JAVA &&
  !jField.isStatic && canBeReadViaGetterFrom(context)
  ) {
- CgMethodCall(variable, getter, emptyList())
+ variable[getter]()
  } else {
  utilsClassId[getFieldValue](variable, this.declaringClass.name, this.name)
  }

utbot-framework/src/main/kotlin/org/utbot/framework/codegen/tree/CgVariableConstructor.kt

@@ -215,7 +215,7 @@ open class CgVariableConstructor(val context: CgContext) :
  } else if (context.codegenLanguage == CodegenLanguage.JAVA &&
  !field.isStatic && fieldId.canBeSetViaSetterFrom(context)
  ) {
- +CgMethodCall(obj, fieldId.setter, listOf(valueForField))
+ +obj[fieldId.setter](valueForField)
  } else {
  // composite models must not have info about static fields, hence only non-static fields are set here
  +utilsClassId[setField](obj, fieldId.declaringClass.name, fieldId.name, valueForField)

utbot-framework/src/main/kotlin/org/utbot/framework/codegen/tree/ConstructorUtils.kt

@@ -291,6 +291,20 @@ internal fun CgContextOwner.typeCast(
  return CgTypeCast(denotableTargetType, expression, isSafetyCast)
 }
 
+/**
+ * Casts [expression] to [targetType] only if downcast is needed,
+ * e.g. this method will cast `Collection` to `Set`, but not vice-versa.
+ *
+ * @see typeCast
+ */
+internal fun CgContextOwner.downcastIfNeeded(
+ targetType: ClassId,
+ expression: CgExpression,
+ isSafetyCast: Boolean = false
+): CgExpression =
+ if (expression.type isSubtypeOf targetType) expression
+ else typeCast(targetType, expression, isSafetyCast)
+
 /**
  * Sets an element of arguments array in parameterized test,
  * if test framework represents arguments as array.