### Is there an existing issue for this? - [x] I have searched the existing issues ### Describe the bug I'm using .NET 9 OpenAPI support. With the following endpoint: ```csharp app.MapPost("/api/documents", ([FromForm] int[] values) => { return TypedResults.Ok(); }); ``` I get the following definition: ```json "requestBody": { "content": { "multipart/form-data": { "schema": { "type": "object", "properties": { "values": { "type": "array", "items": { "type": "integer", "format": "int32" } } } } }, "application/x-www-form-urlencoded": { "schema": { "type": "object", "properties": { "values": { "type": "array", "items": { "type": "integer", "format": "int32" } } } } } }, "required": true } ``` If, instead, I change the type to `IEnumerable`: ```csharp app.MapPost("/api/documents", ([FromForm] IEnumerable<int> values) => { return TypedResults.Ok(); }); ``` The OpenAPI definition becomes: ```json "requestBody": { "content": { "multipart/form-data": { "schema": { "type": "array", "items": { "type": "integer", "format": "int32" } } }, "application/x-www-form-urlencoded": { "schema": { "type": "array", "items": { "type": "integer", "format": "int32" } } } }, "required": true }, ``` ### .NET Version 9.0.301