Infer object type from additionalProperties when type is omitted

[woohyun-park]

Summary

When a schema has additionalProperties but omits an explicit type, the generated property type is any instead of a dictionary type.

Reproduction

{
  "openapi": "3.0.0",
  "info": { "title": "Repro", "version": "1.0.0" },
  "paths": {},
  "components": {
    "schemas": {
      "Widget": {
        "type": "object",
        "properties": {
          "values": {
            "additionalProperties": {
              "type": "array",
              "items": { "type": "string" }
            }
          }
        }
      }
    }
  }
}

Generate types from this schema with the default configuration.

Actual behavior

export interface Widget {
  values?: any;
}

Expected behavior

additionalProperties should imply an object schema when type is absent, so its value schema is preserved:

export interface Widget {
  values?: Record<string, string[]>;
}

This reproduces on main at 1b364b2 (swagger-typescript-api 13.12.6).

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Written by an agent (OpenAI Codex, GPT-5).