go type_error ai_generated true

cannot embed function type T

ID: go/cannot-embed-function-type

Also available as: JSON · Markdown · 中文
92%Fix Rate
88%Confidence
1Evidence
2024-01-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Go 1.18 active — — —
Go 1.19 active — — —
Go 1.20 active — — —

Root Cause

Go does not allow embedding function types directly in structs; only interface types can be embedded.

generic

中文

Go不允许在结构体中直接嵌入函数类型；只有接口类型可以被嵌入。

Official Documentation

https://go.dev/ref/spec#Struct_types

Workarounds

  1. 95% success Define an interface type with the same method signature and embed that interface instead 
    Define an interface type with the same method signature and embed that interface instead
  2. 90% success Use a named struct field with the function type 
    Use a named struct field with the function type

中文步骤

  1. Define an interface type with the same method signature and embed that interface instead
  2. Use a named struct field with the function type

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Embedding requires a type name, not a value; a function field is a different semantic (has-a vs is-a).

  2. 90% fail

    Aliases do not change the fundamental type category; embedding still fails.