API `getSemanticDiagnostics` reports wrong error for code extends interface in namespace

🔎 Search Terms

"getSemanticDiagnostics namespace"

🕗 Version & Regression Information

• I was unable to test this on prior versions because _______

⏯ Playground Link

No response

💻 Code

namespace A {
  export interface C {}
}

interface B extends A.C {
}

🙁 Actual behavior

    messageText: "Cannot extend an interface 'A.C'. Did you mean 'implements'?",
    category: 1,
    code: 2689,
    reportsUnnecessary: undefined,
    reportsDeprecated: undefined

🙂 Expected behavior

No error.

Additional information about the issue

No response

首先通过 getSemanticDiagnostics API 重现 namespace 示例，并跟踪报告错误 2689 的语义诊断。当这段代码不再产生任何诊断，并有一个覆盖扩展 A.C 的 interface 的回归测试时，修复就完成了；该 issue 未指定 repository 文件或测试路径。