{
  "id": "rust/e0437-type-inference-fails-on-generic-impl",
  "signature": "error[E0437]: type `X` does not implement trait `Y` because `Z` is not satisfied",
  "signature_zh": "错误[E0437]：类型 `X` 未实现 trait `Y`，因为 `Z` 不满足",
  "regex": "error\\[E0437\\]: type `[^`]+` does not implement trait `[^`]+` because `[^`]+` is not satisfied",
  "domain": "rust",
  "category": "type_error",
  "subcategory": null,
  "root_cause": "A generic type parameter or associated type lacks a required trait bound, causing the compiler to reject the implementation.",
  "root_cause_type": "generic",
  "root_cause_zh": "泛型类型参数或关联类型缺少必需的 trait 约束，导致编译器拒绝该实现。",
  "versions": [
    {
      "version": "1.68.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "1.70.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "1.72.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Adding a blanket `impl<T> Trait for T` to force satisfaction",
      "why_fails": "Creates conflicting implementations or orphan rules violations, leading to E0119 or E0210.",
      "fail_rate": 0.75,
      "condition": "",
      "sources": []
    },
    {
      "action": "Removing the generic parameter entirely and hardcoding types",
      "why_fails": "Loses genericity; often breaks other callers expecting polymorphism.",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Add the missing trait bound to the generic parameter in the impl block, e.g., `impl<T: Display + Debug> Trait for T { ... }`",
      "success_rate": 0.88,
      "how": "Add the missing trait bound to the generic parameter in the impl block, e.g., `impl<T: Display + Debug> Trait for T { ... }`",
      "condition": "",
      "sources": []
    },
    {
      "action": "Use a where clause to specify the bound on an associated type: `where <T as Iterator>::Item: Clone`",
      "success_rate": 0.85,
      "how": "Use a where clause to specify the bound on an associated type: `where <T as Iterator>::Item: Clone`",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "在 impl 块中为泛型参数添加缺失的 trait 约束，例如 `impl<T: Display + Debug> Trait for T { ... }`",
    "使用 where 子句在关联类型上指定约束：`where <T as Iterator>::Item: Clone`"
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://doc.rust-lang.org/error_codes/E0437.html",
  "official_doc_section": null,
  "error_code": "E0437",
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.82,
  "resolvable": "true",
  "first_seen": "2023-04-15",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}