[Bug]: Failed to generate schema for models with dictionary base occured in 6.7.2

[maantoszyk]

Describe the bug

Issue:
When moving from version 6.7.1 to 6.7.2 there is an issue where the schema for swagger fails to generate and the http status code Internal Server Error is returned.
The problem from exception is: Expected Dictionary to have two generic type arguments but it had 1.

Background:
I am using several base models for API models which is probably causing the problem. One of them is based on the dictionary type. I've been using them since version 5.4.1 without any issues.

Tried:
I tried updating to the latest current version 6.9.0 but it still doesn't fix the issue.

Example:
I made a minimalistic example using my base models to demonstrate the problem. When you downgrade to <6.7.2 it should work.

Expected behavior

No response

Actual behavior

No response

Steps to reproduce

https://github.com/maantoszyk/swagger-bug-report

Exception(s) (if any)

Swashbuckle.AspNetCore.SwaggerGen.SwaggerGeneratorException: Failed to generate Operation for action - DictionaryIssueMinimalExample.Controllers.CategoryController.Get (DictionaryIssueMinimalExample). See inner exception
 ---> Swashbuckle.AspNetCore.SwaggerGen.SwaggerGeneratorException: Failed to generate schema for type - System.Collections.Generic.IEnumerable`1[DictionaryIssueMinimalExample.Models.CategoryModel]. See inner exception
 ---> System.InvalidOperationException: Expected Dictionary to have two generic type arguments but it had 1. Member: DictionaryIssueMinimalExample.Models.Base.LocalizedEntityModel`2[[System.Int32, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[DictionaryIssueMinimalExample.Models.CategoryLocalizationModel, DictionaryIssueMinimalExample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].Localization Type: DictionaryIssueMinimalExample.Models.Base.LocalizationModel`1[[DictionaryIssueMinimalExample.Models.CategoryLocalizationModel, DictionaryIssueMinimalExample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].
   at Swashbuckle.AspNetCore.SwaggerGen.MemberInfoExtensions.IsDictionaryValueNonNullable(MemberInfo memberInfo)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchemaForMember(Type modelType, SchemaRepository schemaRepository, MemberInfo memberInfo, DataProperty dataProperty)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.CreateObjectSchema(DataContract dataContract, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.<>c__DisplayClass13_0.<GenerateConcreteSchema>b__3()
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateReferencedSchema(DataContract dataContract, SchemaRepository schemaRepository, Func`1 definitionFactory)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateConcreteSchema(DataContract dataContract, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchemaForType(Type modelType, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchema(Type modelType, SchemaRepository schemaRepository, MemberInfo memberInfo, ParameterInfo parameterInfo, ApiParameterRouteInfo routeInfo)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.CreateArraySchema(DataContract dataContract, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.<>c__DisplayClass13_0.<GenerateConcreteSchema>b__1()
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateConcreteSchema(DataContract dataContract, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchemaForType(Type modelType, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchema(Type modelType, SchemaRepository schemaRepository, MemberInfo memberInfo, ParameterInfo parameterInfo, ApiParameterRouteInfo routeInfo)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateSchema(Type type, SchemaRepository schemaRepository, PropertyInfo propertyInfo, ParameterInfo parameterInfo, ApiParameterRouteInfo routeInfo)
   --- End of inner exception stack trace ---
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateSchema(Type type, SchemaRepository schemaRepository, PropertyInfo propertyInfo, ParameterInfo parameterInfo, ApiParameterRouteInfo routeInfo)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.CreateResponseMediaType(Type modelType, SchemaRepository schemaRespository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.<>c__DisplayClass40_0.<GenerateResponse>b__2(String contentType)
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateResponse(ApiDescription apiDescription, SchemaRepository schemaRepository, String statusCode, ApiResponseType apiResponseType)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateResponses(ApiDescription apiDescription, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperationAsync(ApiDescription apiDescription, SchemaRepository schemaRepository, Func`3 parametersGenerator, Func`3 bodyGenerator, Func`3 applyFilters)
   --- End of inner exception stack trace ---
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperationAsync(ApiDescription apiDescription, SchemaRepository schemaRepository, Func`3 parametersGenerator, Func`3 bodyGenerator, Func`3 applyFilters)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperationAsync(ApiDescription apiDescription, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperationsAsync(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePathsAsync(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository, Func`3 operationsGenerator)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePathsAsync(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwaggerAsync(String documentName, String host, String basePath)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

Swashbuckle.AspNetCore version

6.7.2

.NET Version

.NET 8

Anything else?

[martincostello]

Issue is due to this check:

Swashbuckle.AspNetCore/src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/MemberInfoExtensions.cs

Line 88 in da07a53

if (nullableInfo.GenericTypeArguments.Length != 2)

Which isn't handling this type:

public class LocalizationModel<TLocalization> : Dictionary<string, TLocalization>;

This is essentially a duplicate of #3070. See #3070 (comment).